“Darwin’s Sacred Quest” Book Review
Adrian Desmond devotes about 470 pages to revealing what he believes is the secret truth to Darwin’s motivations for creating his theories of evolution and natural selection. While his theory that abolitionist tendencies and an inner moral compass that swings heavily toward black and white equality is what actually drove Darwin’s scientific work may be a large part of Darwin’s thought process, I don’t think Desmond gives enough credit to other facets of Darwin’s personality or moral upbringing. The entire book is well thought out, and shows Desmond’s evident extensive research into Darwin’s letters, his relatives’ writing, and other anecdotes regarding Darwin’s life. Also, Desmond’s ability to link Darwin to even the tiniest encounters or parallel paths to other abolitionists or even pro-slavery campaigners that may have challenged his beliefs is commendable. The book is essentially one giant anecdotal reference, which relies on name dropping and Desmond’s fantastic skills as a Darwin biographer. While the idea of Darwin as an abolitionist is interesting and probably worth fleshing out, this book might go well paired with a more traditional and less experimental viewpoint as a foil to its tome-size researching.
Enjoy!
Kaitlyn
Sunday, May 31, 2009
Project Electric Eel
Darwin wrote in the chapter, "Difficulties on Theory" in "The Origin of Species" that he could not explain why some unrelated fishes had electricity.
Modern scientists are now pushing for the sequencing of the entire electric eel genome, thinking that it will benefit energy production and storage and even tissue regeneration.
Electric eels, Electrophorus electricus, are able to generate bioelectricity from chemical food energy using their specialized electric organs that house electrically-charged cells with specially regulated ion channels and receptors. The eel can generate a range of electrical pulses from the millivolt level to as strong as 600 volts!
Unraveling the DNA code of electric eels is not just for kicks to acquire the information but apparently can also help produce DNA microchips for gene expression experiments. Understanding the electric eel's electricity facilitating genetics and physiology will also allow the development of biobatteries and even bioreporters that label cells with electricity rather than the light emission, such as green fluorescent protein! What would be the advantage of electricity over light I wonder? This could potentially be a Nobel-prize winning discovery just like GFP! Perhaps electricity can eliminate complications such as photobleaching, phototoxicity, imperfect transgene expression, etc.
Interestingly, the scientists who are pushing for this research claim that sequencing the electric eel genome coalesces well with efforts by the US Department of Energy Joint Genome Institute Community Sequencing Program to generate bioinformatics that of utmost scientific and societal importance "in organisms other than those related directly to human disease or traditional model organisms." I think this offers quite a fresh outlook to the purpose and significance of investigation. The electric eel may in fact be of some medical importance as well because it is able to regenerate its spinal cord after injury. Stem cells may be potentially harnessed for use in neurodegenerative diseases. Studying this fascinating organism's genome will be able to shed some light on its complex evolution and neurophysiology. Since Darwin did not have technology or DNA knowledge accessible to him at the time, he was thus probably unable to explain the electric eel evolutionary phenomenon. Side note - I remember discussing in class how it's absurd to say that Darwin would've gotten everything right if he had known everything we know today. I must say that the work on electric eels, which is still in its infancy, does reveal the difficulty all scientists, not just Darwin, have had with understanding the creature's unique features. I'm not saying that Darwin would've gotten everything right even with all the necessary pieces of knowledge in front of him - that would depend on how he interpreted the information! But anyway, sadly, the electric eel project was rejected because of the high price tag in the millions!
http://www.genomeweb.com/scientists-push-electric-eel-genome-research
-Bonnie Chien
Modern scientists are now pushing for the sequencing of the entire electric eel genome, thinking that it will benefit energy production and storage and even tissue regeneration.
Electric eels, Electrophorus electricus, are able to generate bioelectricity from chemical food energy using their specialized electric organs that house electrically-charged cells with specially regulated ion channels and receptors. The eel can generate a range of electrical pulses from the millivolt level to as strong as 600 volts!
Unraveling the DNA code of electric eels is not just for kicks to acquire the information but apparently can also help produce DNA microchips for gene expression experiments. Understanding the electric eel's electricity facilitating genetics and physiology will also allow the development of biobatteries and even bioreporters that label cells with electricity rather than the light emission, such as green fluorescent protein! What would be the advantage of electricity over light I wonder? This could potentially be a Nobel-prize winning discovery just like GFP! Perhaps electricity can eliminate complications such as photobleaching, phototoxicity, imperfect transgene expression, etc.
Interestingly, the scientists who are pushing for this research claim that sequencing the electric eel genome coalesces well with efforts by the US Department of Energy Joint Genome Institute Community Sequencing Program to generate bioinformatics that of utmost scientific and societal importance "in organisms other than those related directly to human disease or traditional model organisms." I think this offers quite a fresh outlook to the purpose and significance of investigation. The electric eel may in fact be of some medical importance as well because it is able to regenerate its spinal cord after injury. Stem cells may be potentially harnessed for use in neurodegenerative diseases. Studying this fascinating organism's genome will be able to shed some light on its complex evolution and neurophysiology. Since Darwin did not have technology or DNA knowledge accessible to him at the time, he was thus probably unable to explain the electric eel evolutionary phenomenon. Side note - I remember discussing in class how it's absurd to say that Darwin would've gotten everything right if he had known everything we know today. I must say that the work on electric eels, which is still in its infancy, does reveal the difficulty all scientists, not just Darwin, have had with understanding the creature's unique features. I'm not saying that Darwin would've gotten everything right even with all the necessary pieces of knowledge in front of him - that would depend on how he interpreted the information! But anyway, sadly, the electric eel project was rejected because of the high price tag in the millions!
http://www.genomeweb.com/scientists-push-electric-eel-genome-research
-Bonnie Chien
Robots with fins, tails demonstrate evolution
http://www.google.com/hostednews/ap/article/ALeqM5h-OM7D-GWQnzYxnIHkC5l2ESariQD98G0Q901
Currently, a worldwide contingent of researchers and scientists are studying and testing various mechanism of evolution using state-of-the-art technology. This article looks at the current project being conducted on natural selection in the Vassar College biology and cognitive science department laboratories. In it, two swimming robots chase each other in a predator and prey manner. The prey robot, appropriately named Preygo, possesses customizable features (i.e. fin shape, fin size, body size/shape, etc.) that are carefully adjusted to see which set of traits provides it the highest probability of success in escaping the predator robot, Tadiator. Doing so, the researchers hope to mimic the process of natural selection.
The Vassar College experiments are just one of the many that employs robots to test the theories of evolution. As technology advances, so does the resemblance of the robots to the animals they're mimicking and likewise, researchers hope, the accuracy of their collected data. These developments can be found in the robotic cockroaches and geckos in Berkeley's integrative science lab, salamanders in Switzerland, and more fish in Harvard organismic and evolutionary biology lab. Research and development usually target a specific part of the animal, such as the fin or spinal column and use it for the dependent variable of their experiments. Then they set them loose in a simulated evolutionary scenario.
Technology can also create computer simulated evolutionary scenarios. However, the researchers said they don't prefer this method because there are some kinks in it that defy the law of physics. Either way, researchers seem extremely excited about the prospects and new information that the use of technology in evolutionary research can generate.
One question I have regarding these efforts is to the data's strength as evidence as support for either side of the heated evolution/creationism debate. It seems that the experiments identifies the most potent survival trait in various animals and researchers use the results to draw an inordinately strong correlation with the existence of natural selection. However, the results don't clarify what the origin of species is and so shouldn't be used in the debate. Another question I have regards the strength of the correlation scientists' draw. I personally feel that these types of experiments are always too physics based and cannot account for strange natural phenomenon. Likely, this very doubt of mine surfaces my belief in some sort of divine intervention. Anyway, specific to the experiments discussed in the article, I don't feel they have much use outside of intellectual, industrial, and military interests.
I think it's interesting that we have the technological mastery to artificially mimic natural selection and essentially, recreate evolution. Luckily, right now its only for the purpose of quelling our own curiosity towards our origin and experiments are conducted in a very controlled environment. However, I know I might be going on a tangent here, but as with all scientific endeavors towards understanding ourselves, there's a dangerous potential involved fit for sci-fi horror films. I wonder when they will recreate the experiment using human traits. When they do, then the door opens to the possibility of enhancing humans with superior predatorial characteristics. Anyway, I'm probably just being imaginative and excessively paranoid but I'm always wary of the fusion of biology and science.
-teresa
Currently, a worldwide contingent of researchers and scientists are studying and testing various mechanism of evolution using state-of-the-art technology. This article looks at the current project being conducted on natural selection in the Vassar College biology and cognitive science department laboratories. In it, two swimming robots chase each other in a predator and prey manner. The prey robot, appropriately named Preygo, possesses customizable features (i.e. fin shape, fin size, body size/shape, etc.) that are carefully adjusted to see which set of traits provides it the highest probability of success in escaping the predator robot, Tadiator. Doing so, the researchers hope to mimic the process of natural selection.
The Vassar College experiments are just one of the many that employs robots to test the theories of evolution. As technology advances, so does the resemblance of the robots to the animals they're mimicking and likewise, researchers hope, the accuracy of their collected data. These developments can be found in the robotic cockroaches and geckos in Berkeley's integrative science lab, salamanders in Switzerland, and more fish in Harvard organismic and evolutionary biology lab. Research and development usually target a specific part of the animal, such as the fin or spinal column and use it for the dependent variable of their experiments. Then they set them loose in a simulated evolutionary scenario.
Technology can also create computer simulated evolutionary scenarios. However, the researchers said they don't prefer this method because there are some kinks in it that defy the law of physics. Either way, researchers seem extremely excited about the prospects and new information that the use of technology in evolutionary research can generate.
One question I have regarding these efforts is to the data's strength as evidence as support for either side of the heated evolution/creationism debate. It seems that the experiments identifies the most potent survival trait in various animals and researchers use the results to draw an inordinately strong correlation with the existence of natural selection. However, the results don't clarify what the origin of species is and so shouldn't be used in the debate. Another question I have regards the strength of the correlation scientists' draw. I personally feel that these types of experiments are always too physics based and cannot account for strange natural phenomenon. Likely, this very doubt of mine surfaces my belief in some sort of divine intervention. Anyway, specific to the experiments discussed in the article, I don't feel they have much use outside of intellectual, industrial, and military interests.
I think it's interesting that we have the technological mastery to artificially mimic natural selection and essentially, recreate evolution. Luckily, right now its only for the purpose of quelling our own curiosity towards our origin and experiments are conducted in a very controlled environment. However, I know I might be going on a tangent here, but as with all scientific endeavors towards understanding ourselves, there's a dangerous potential involved fit for sci-fi horror films. I wonder when they will recreate the experiment using human traits. When they do, then the door opens to the possibility of enhancing humans with superior predatorial characteristics. Anyway, I'm probably just being imaginative and excessively paranoid but I'm always wary of the fusion of biology and science.
-teresa
Book Review: Voyage of the Beagle!
For the first several pages of Voyage of the Beagle, Darwin’s 22-year-old excitement for his impending round-the-world trip was infectious. I was swept along by his narrative, and excited to be reading about such a legendary journey.
“Delight…is a weak term to express the feelings of a naturalist who, for the first time, has wandered by himself in a Brazilian forest,” he writes during one of the Beagle’s first stops in Brazil. “The elegance of the grasses, the novelty of the parasitical plants, the beauty of the flowers, the glossy green of the foliage, but above all the general luxuriance of the vegetation, filled me with admiration. A most paradoxical mixture of sound and silence pervades the shady parts of the wood. The noise from the insects is so loud, that it may be heard even in a vessel anchored several hundred yards from the shore; yet within the recesses of the forest a universal silence appears to reign. To a person fond of natural history, such a day as this brings with it a deeper pleasure than he can ever hope to experience again.”
The Voyage, in those early pages, seemed more like a surprisingly well-written adventure novel than a journal. Each page was filled with Darwin’s boundlessly enthusiastic descriptions of new plants, creatures, and people.
But then it continued…and continued. Darwin’s prose, initially so fresh, soon took on an air of perpetual excitement that made my eyes glaze over. Detailed descriptions of flora and fauna, once endearing, became excruciating. As a lover of nature and biology, I felt almost bad that I couldn’t muster up Darwin’s continual enthusiasm for every. Single. Thing.
From a literary standpoint, then, I was disappointed to find the Voyage an almost unbearably boring read. As an historical artifact, however, I think it has immense value. It is a rare and kind of amazing thing that we’re able to read Darwin’s firsthand account of such a legendary event in biological (and world) history, and by going back to the primary source, we notice things that get left out of oft-repeated secondary and tertiary accounts.
Some of those are things we’ve discussed in class—the fact that Darwin spent relatively little time in the Galapagos, for example, or on the Beagle at all. He preferred to walk from port to port, and was actually onboard ship for only 533 days out of the nearly five years the Beagle was at sea.
Other things caught my eye, as well. We all think of Darwin as a curious person and a scientist at heart, but the Voyage makes it particularly clear what joy he took in undiscovered knowledge. He often poses questions—about how a specific animal functions, for example—and then (very happily, it seems) declares he has no idea what the answer might be. About a species of fish in Bahia, Brazil, he writes, “It emitted from the skin of its belly, when handled, a most beautiful carmine red and fibrous secretion, which stained ivory and paper in so permanent a manner, that the tint is retained with all its brightness to the present day. I am quite ignorant of the nature of and use of this secretion.”
Darwin is sometimes blatantly “unscientific.” He frequently personifies both the animals and plants that he finds, and even demeans them—as in the case of the Brazilian Tucotuco, which he describes as “very stupid.” Moments like this, I think, remind us that Darwin is incredibly young on the Beagle, still child-like, wondering about and reacting to the things he finds. In many ways that child-like curiosity never really leaves him, as we’ve seen in artifacts like the “weed garden” at Down House.
The Voyage also brings out Darwin’s complex attitude towards other races. This is often left out of secondary accounts of his life, where he's portrayed purely as a proponent of equality, arguing nobly against slavery with Captain FitzRoy.
Darwin does disapprove of slavery, and he feels sympathy for those who are oppressed. But he also looks down upon them: to Darwin, equality will come from the imposition of “civilized” culture on savage races. He concludes the Voyage by talking about “the march of improvement” through the uncivilized world, and the beneficial changes “effected by the philanthropic spirit of the British nation.” He writes that he believes the native people of South America to exist “in a lower state of improvement than in any other part of the world.”
Is the slog through Darwin’s prose worth it for a better understanding of these nuances? To me, that question is a broader one—about the value of primary sources, overall. Going back to original documents, although sometimes hard to access and harder to read, is the only real way to come to independent conclusions about an idea or event. And it's key to keeping old ideas alive and fresh. So, reading Darwin’s own words, although more time-consuming (and maybe painful) than skimming an expert’s summary of them, is how new reinterpretations and perspectives will emerge to keep Darwin’s works around for another 200 years.
Conclusion? Reading primary sources is important. But beware—the Beagle might be excruciating. Unless you are into pages-long descriptions of geological formations.
Anne
“Delight…is a weak term to express the feelings of a naturalist who, for the first time, has wandered by himself in a Brazilian forest,” he writes during one of the Beagle’s first stops in Brazil. “The elegance of the grasses, the novelty of the parasitical plants, the beauty of the flowers, the glossy green of the foliage, but above all the general luxuriance of the vegetation, filled me with admiration. A most paradoxical mixture of sound and silence pervades the shady parts of the wood. The noise from the insects is so loud, that it may be heard even in a vessel anchored several hundred yards from the shore; yet within the recesses of the forest a universal silence appears to reign. To a person fond of natural history, such a day as this brings with it a deeper pleasure than he can ever hope to experience again.”
The Voyage, in those early pages, seemed more like a surprisingly well-written adventure novel than a journal. Each page was filled with Darwin’s boundlessly enthusiastic descriptions of new plants, creatures, and people.
But then it continued…and continued. Darwin’s prose, initially so fresh, soon took on an air of perpetual excitement that made my eyes glaze over. Detailed descriptions of flora and fauna, once endearing, became excruciating. As a lover of nature and biology, I felt almost bad that I couldn’t muster up Darwin’s continual enthusiasm for every. Single. Thing.
From a literary standpoint, then, I was disappointed to find the Voyage an almost unbearably boring read. As an historical artifact, however, I think it has immense value. It is a rare and kind of amazing thing that we’re able to read Darwin’s firsthand account of such a legendary event in biological (and world) history, and by going back to the primary source, we notice things that get left out of oft-repeated secondary and tertiary accounts.
Some of those are things we’ve discussed in class—the fact that Darwin spent relatively little time in the Galapagos, for example, or on the Beagle at all. He preferred to walk from port to port, and was actually onboard ship for only 533 days out of the nearly five years the Beagle was at sea.
Other things caught my eye, as well. We all think of Darwin as a curious person and a scientist at heart, but the Voyage makes it particularly clear what joy he took in undiscovered knowledge. He often poses questions—about how a specific animal functions, for example—and then (very happily, it seems) declares he has no idea what the answer might be. About a species of fish in Bahia, Brazil, he writes, “It emitted from the skin of its belly, when handled, a most beautiful carmine red and fibrous secretion, which stained ivory and paper in so permanent a manner, that the tint is retained with all its brightness to the present day. I am quite ignorant of the nature of and use of this secretion.”
Darwin is sometimes blatantly “unscientific.” He frequently personifies both the animals and plants that he finds, and even demeans them—as in the case of the Brazilian Tucotuco, which he describes as “very stupid.” Moments like this, I think, remind us that Darwin is incredibly young on the Beagle, still child-like, wondering about and reacting to the things he finds. In many ways that child-like curiosity never really leaves him, as we’ve seen in artifacts like the “weed garden” at Down House.
The Voyage also brings out Darwin’s complex attitude towards other races. This is often left out of secondary accounts of his life, where he's portrayed purely as a proponent of equality, arguing nobly against slavery with Captain FitzRoy.
Darwin does disapprove of slavery, and he feels sympathy for those who are oppressed. But he also looks down upon them: to Darwin, equality will come from the imposition of “civilized” culture on savage races. He concludes the Voyage by talking about “the march of improvement” through the uncivilized world, and the beneficial changes “effected by the philanthropic spirit of the British nation.” He writes that he believes the native people of South America to exist “in a lower state of improvement than in any other part of the world.”
Is the slog through Darwin’s prose worth it for a better understanding of these nuances? To me, that question is a broader one—about the value of primary sources, overall. Going back to original documents, although sometimes hard to access and harder to read, is the only real way to come to independent conclusions about an idea or event. And it's key to keeping old ideas alive and fresh. So, reading Darwin’s own words, although more time-consuming (and maybe painful) than skimming an expert’s summary of them, is how new reinterpretations and perspectives will emerge to keep Darwin’s works around for another 200 years.
Conclusion? Reading primary sources is important. But beware—the Beagle might be excruciating. Unless you are into pages-long descriptions of geological formations.
Anne
Thursday, May 28, 2009
FOXP2 Gene Alters Sound Production in Mice
-C. Paula de los Angeles
As discussed in class, FOXP2, a human gene thought to be involved in language, may provide clues as to how the brain or more specially, music developed. A recent study done by Dr. Enard of the Max Planck Institute for Evolutionary Anthropology in Leipzig just published a paper in Cell on their findings of their newly genetically engineered strain of mice whose FOXP2 gene has been swapped out for the human version.
The insert of the human FOX2 gene changed multiple functions in the mice, including the sounds that mice use to communicate with each other. In fact, when these mice were isolated, they whistled at lower pitches. Dr. Enard confirmed that the human version of FOXP2 was a perfect substitute for the mouse version in all of the tissues except. Specifically, in the basal ganglia of the brain, these genetically engineered mice had more complexly structured nerve cells.
Perhaps, this study sheds greater light on the role of FOXP2 in language and brain development. Previous studies only concluded that a defect in this gene led to speech, articulation, and grammar problems. The expression of this gene in mice has great potential for future studies.
Primary article: http://www.cell.com/fulltext/S0092-8674(09)00378-X
News article: http://www.nytimes.com/2009/05/29/science/29mouse.html?_r=1&ref=science
As discussed in class, FOXP2, a human gene thought to be involved in language, may provide clues as to how the brain or more specially, music developed. A recent study done by Dr. Enard of the Max Planck Institute for Evolutionary Anthropology in Leipzig just published a paper in Cell on their findings of their newly genetically engineered strain of mice whose FOXP2 gene has been swapped out for the human version.
The insert of the human FOX2 gene changed multiple functions in the mice, including the sounds that mice use to communicate with each other. In fact, when these mice were isolated, they whistled at lower pitches. Dr. Enard confirmed that the human version of FOXP2 was a perfect substitute for the mouse version in all of the tissues except. Specifically, in the basal ganglia of the brain, these genetically engineered mice had more complexly structured nerve cells.
Perhaps, this study sheds greater light on the role of FOXP2 in language and brain development. Previous studies only concluded that a defect in this gene led to speech, articulation, and grammar problems. The expression of this gene in mice has great potential for future studies.
Primary article: http://www.cell.com/fulltext/S0092-8674(09)00378-X
News article: http://www.nytimes.com/2009/05/29/science/29mouse.html?_r=1&ref=science
Tuesday, May 26, 2009
"Darwinism"
Carl Safina wrote an interesting essay for the New York Times about how Darwinism Must Die So That Evolution May Live.
This article reminded me of a favorite Dr. Bob “myth”: Darwinism is not Evolution.
I thought that Safina’s essay made several good points, but one of it’s premises is that scientists are equating Darwinism and evolution. I would say that scientists are apt to honor Darwin and his ideas, but those who are less involved in science are the ones who propagate the idea that Darwinism = Evolution. If anyone realizes how far evolution has come from Darwin’s Origin, it’s scientists. If anyone realizes the importance of advances in the fields of genetics – which wasn’t even a part of the field of evolution during Darwin’s time – it’s scientists. I would argue that popular culture, religious debate, the general news media – really anyone BUT scientists – are responsible for equating Darwinism and Evolution.
These are some particularly notable lines/passages in the essay:
Charles Darwin gets so much credit, we can’t distinguish evolution from him.
…
Equating evolution with Charles Darwin ignores 150 years of discoveries, including most of what scientists understand about evolution.
…
Science has marched on. But evolution can seem uniquely stuck on its founder. We don’t call astronomy Copernicism, nor gravity Newtonism. “Darwinism” implies an ideology adhering to one man’s dictates, like Marxism. And “isms” (capitalism, Catholicism, racism) are not science. “Darwinism” implies that biological scientists “believe in” Darwin’s “theory.” It’s as if, since 1860, scientists have just ditto-headed Darwin rather than challenging and testing his ideas, or adding vast new knowledge.
-Lauren
This article reminded me of a favorite Dr. Bob “myth”: Darwinism is not Evolution.
I thought that Safina’s essay made several good points, but one of it’s premises is that scientists are equating Darwinism and evolution. I would say that scientists are apt to honor Darwin and his ideas, but those who are less involved in science are the ones who propagate the idea that Darwinism = Evolution. If anyone realizes how far evolution has come from Darwin’s Origin, it’s scientists. If anyone realizes the importance of advances in the fields of genetics – which wasn’t even a part of the field of evolution during Darwin’s time – it’s scientists. I would argue that popular culture, religious debate, the general news media – really anyone BUT scientists – are responsible for equating Darwinism and Evolution.
These are some particularly notable lines/passages in the essay:
Charles Darwin gets so much credit, we can’t distinguish evolution from him.
…
Equating evolution with Charles Darwin ignores 150 years of discoveries, including most of what scientists understand about evolution.
…
Science has marched on. But evolution can seem uniquely stuck on its founder. We don’t call astronomy Copernicism, nor gravity Newtonism. “Darwinism” implies an ideology adhering to one man’s dictates, like Marxism. And “isms” (capitalism, Catholicism, racism) are not science. “Darwinism” implies that biological scientists “believe in” Darwin’s “theory.” It’s as if, since 1860, scientists have just ditto-headed Darwin rather than challenging and testing his ideas, or adding vast new knowledge.
-Lauren
Evolution of the Modern House Cat
-Alyssa Martin
Why have cats become such a fixture in the human home when they have little to offer people in the way of survival? Most animals that have become domesticated served some purpose or another – sustenance, labor, clothing, etc. – and were pack-oriented and conducive to confinement. Recent studies on the evolution of the modern house cat have shed light on this curiosity, and have dispelled some of our misconceptions about the cat’s origins.
According to an article in the Scientific American, scholars originally believed that “the ancient Egyptians were the first to keep cats as pets, starting around 3,600 years ago.” Just as Darwin believed that the pigeons of England were descended from a common rock pigeon, scholars maintained that all domesticated cats descend from a common Felix silvestris or wildcat. Because the wildcat has emerged all across the Old World (from Scotland to Mongolia), oftentimes breeding freely with the domestic cat, scientists have had a difficult time uncovering the origins of the wildcat.
In 2000, a genetic team set out to solve this mystery by analyzing the DNA samples (mitochondrial and microsatellite) of “some 979 wildcats and domestic cats in southern Africa, Azerbaijan, Kazakhstan, Mongolia and the Middle East.” The origins of the house cat would depend upon where the closest regional resemblance between wildcat DNA and domestic cat DNA could be established.
The results showed five genetic groupings or lineages, including the four wildcat subspecies “F. silvestris silvestris in Europe, F.s. bieti in China, F.s. ornata in Central Asia and F.s. cafra in southern Africa.” The fifth wildcat subspecies, F.s. lybica in the Middle East, also included all domestic cat DNA’s sampled. Clearly, domestic cats originated in the Middle East. Scientists were able to roughly establish when domestication occurred by examining the archaeological record, which showed that the first evidence of a pet cat emerged in Cyprus around 9,5000 years ago. Scientists inferred that cats must have been taken to Cyprus by boat from the Levantine coast; this suggests that “people had a special, intentional relationship with cats nearly 10,000 years ago in the Middle East,” or when the first civilizations emerged in the Fertile Crescent.
Because of the limited utility of cats for humans, it is likely that cats gravitated toward humans rather than vice versa. Scientists now believe that the emergence of the house mouse, Mus musculus domesticus, coincided with the emergence of the house cat, which was eager to exploit this development – “in the lingo of evolutionary biology, natural selection favored those cats that were able to cohabitate with humans and thereby gain access to the trash and mice.” As cats began dispensing with rodents, people probably saw the merit in keeping them (apart from their obvious aesthetic appeal).
Ultimately, domestication likely took thousands of years, as “the lack of human influence on breeding and the probable intermixing of house cats and wildcats militated against rapid taming.” It was not until Egyptian paintings from around 3,600 years ago that scholars were able to confirm full and robust cat domestication. In fact, the Egyptians were known for cat worship, as the cat goddess Bastet became the official deity of Egypt. Although Egypt tried to block the export of cats, cats were eventually propagated on grain ships and throughout the Roman Empire. Interestingly, “because no native wildcats with which the [domestic] newcomers could interbreed lived in the Far East, the Oriental domestic cats soon began evolving along their own trajectory.” This occurrence fostered genetic drift, which in turn led to the appearance of the very distinct Korat, Siamese, and Burman.
Breeding for particular traits did not occur among cats until relatively recently in the British Isles. In 1871, the “first proper fancy cat breeds—breeds created by humans to achieve a particular appearance—were displayed at a cat show” in London. A closer look at the cat genome has begun to reveal the origin of certain traits like tabby patterning, coloring, hair length, etc. Despite the people-friendly evolution and domestication of the cat, the domestic cat still retains many features of the wild cat. However, a couple traits have evolved to fit the domestic cat’s new lifestyle: shorter legs, smaller brain, and, as Charles Darwin observed, a longer intestine adapted to digesting kitchen scraps.
Why have cats become such a fixture in the human home when they have little to offer people in the way of survival? Most animals that have become domesticated served some purpose or another – sustenance, labor, clothing, etc. – and were pack-oriented and conducive to confinement. Recent studies on the evolution of the modern house cat have shed light on this curiosity, and have dispelled some of our misconceptions about the cat’s origins.
According to an article in the Scientific American, scholars originally believed that “the ancient Egyptians were the first to keep cats as pets, starting around 3,600 years ago.” Just as Darwin believed that the pigeons of England were descended from a common rock pigeon, scholars maintained that all domesticated cats descend from a common Felix silvestris or wildcat. Because the wildcat has emerged all across the Old World (from Scotland to Mongolia), oftentimes breeding freely with the domestic cat, scientists have had a difficult time uncovering the origins of the wildcat.
In 2000, a genetic team set out to solve this mystery by analyzing the DNA samples (mitochondrial and microsatellite) of “some 979 wildcats and domestic cats in southern Africa, Azerbaijan, Kazakhstan, Mongolia and the Middle East.” The origins of the house cat would depend upon where the closest regional resemblance between wildcat DNA and domestic cat DNA could be established.
The results showed five genetic groupings or lineages, including the four wildcat subspecies “F. silvestris silvestris in Europe, F.s. bieti in China, F.s. ornata in Central Asia and F.s. cafra in southern Africa.” The fifth wildcat subspecies, F.s. lybica in the Middle East, also included all domestic cat DNA’s sampled. Clearly, domestic cats originated in the Middle East. Scientists were able to roughly establish when domestication occurred by examining the archaeological record, which showed that the first evidence of a pet cat emerged in Cyprus around 9,5000 years ago. Scientists inferred that cats must have been taken to Cyprus by boat from the Levantine coast; this suggests that “people had a special, intentional relationship with cats nearly 10,000 years ago in the Middle East,” or when the first civilizations emerged in the Fertile Crescent.
Because of the limited utility of cats for humans, it is likely that cats gravitated toward humans rather than vice versa. Scientists now believe that the emergence of the house mouse, Mus musculus domesticus, coincided with the emergence of the house cat, which was eager to exploit this development – “in the lingo of evolutionary biology, natural selection favored those cats that were able to cohabitate with humans and thereby gain access to the trash and mice.” As cats began dispensing with rodents, people probably saw the merit in keeping them (apart from their obvious aesthetic appeal).
Ultimately, domestication likely took thousands of years, as “the lack of human influence on breeding and the probable intermixing of house cats and wildcats militated against rapid taming.” It was not until Egyptian paintings from around 3,600 years ago that scholars were able to confirm full and robust cat domestication. In fact, the Egyptians were known for cat worship, as the cat goddess Bastet became the official deity of Egypt. Although Egypt tried to block the export of cats, cats were eventually propagated on grain ships and throughout the Roman Empire. Interestingly, “because no native wildcats with which the [domestic] newcomers could interbreed lived in the Far East, the Oriental domestic cats soon began evolving along their own trajectory.” This occurrence fostered genetic drift, which in turn led to the appearance of the very distinct Korat, Siamese, and Burman.
Breeding for particular traits did not occur among cats until relatively recently in the British Isles. In 1871, the “first proper fancy cat breeds—breeds created by humans to achieve a particular appearance—were displayed at a cat show” in London. A closer look at the cat genome has begun to reveal the origin of certain traits like tabby patterning, coloring, hair length, etc. Despite the people-friendly evolution and domestication of the cat, the domestic cat still retains many features of the wild cat. However, a couple traits have evolved to fit the domestic cat’s new lifestyle: shorter legs, smaller brain, and, as Charles Darwin observed, a longer intestine adapted to digesting kitchen scraps.
Monday, May 25, 2009
Darwin's Great Great Granddaughter Resigns as Oxford's Female Professor of Poetry
-C. Paula de los Angeles
Although we witnessed Ruth Padel, Darwin's great great granddaughter make history as she was the first woman to be awarded the selective professorship of poetry at Oxford (started in 1708) last week, we can't applaud just yet. Previous winners include W.H. Auden and Seamus Heaney. The award of her prestigious professorship was shocking not only because she was the first woman, but because she won over Nobel-laureate winner Derek Walcott (This is not to say that Padel was not also recognized as a great poet, as she has won many national awards). Walcott withdrew from the race after Pandel leaked to the media that a previous Harvard student of Walcott's made sexual allegations against him in the 1980s. After The Sunday Times published emails that she had sent to the media, Padel has decided to resign.
Scandal! I wonder how this act may change how people view her poetry on Darwin...
News article link: http://www.nytimes.com/aponline/2009/05/25/books/AP-EU-Britain-Poetry-Professor.html?em
Sample of Padel's poetry:
The Miser
(from Chapter One: Boy (1809-1831)
The passion for collecting, which leads a man to be a miser, a virtuoso, or a systematic naturalist, was very strong in me. It was clearly innate. None of my sisters or brother had this taste.
Darwin, Autobiography
Cross the Welsh Bridge out of town, go up the hill
on Frankwell Street and you'll see, above the Severn,
brick pillars with the sandy bloom of an ageing dog.
Around the back, Father's surgery and waiting-room.
Outside, the Stable Yard: hay chutes, a piggery and toolshed.
Lower down, a bothy on the river bank
where plates of jagged ice, harvested in winter from the river,
lean one against the other. A dairy, where these blocks are dragged
to cool the milk and cream. The Quarry Pool
where he fishes for newts and tadpoles.
Collecting: to assert control
over what's unbearable. To gather and to list.
'Stones, coins, franks, insects, minerals and shells.'
Collect yourself: to smother what you feel,
recall to order, summon in one place;
making, like Orpheus, a system against loss.
(Editor's note: Darwin's father was an affluent doctor. The estate of his house, The Mount, bordered the River Severn)
Although we witnessed Ruth Padel, Darwin's great great granddaughter make history as she was the first woman to be awarded the selective professorship of poetry at Oxford (started in 1708) last week, we can't applaud just yet. Previous winners include W.H. Auden and Seamus Heaney. The award of her prestigious professorship was shocking not only because she was the first woman, but because she won over Nobel-laureate winner Derek Walcott (This is not to say that Padel was not also recognized as a great poet, as she has won many national awards). Walcott withdrew from the race after Pandel leaked to the media that a previous Harvard student of Walcott's made sexual allegations against him in the 1980s. After The Sunday Times published emails that she had sent to the media, Padel has decided to resign.
Scandal! I wonder how this act may change how people view her poetry on Darwin...
News article link: http://www.nytimes.com/aponline/2009/05/25/books/AP-EU-Britain-Poetry-Professor.html?em
Sample of Padel's poetry:
The Miser
(from Chapter One: Boy (1809-1831)
The passion for collecting, which leads a man to be a miser, a virtuoso, or a systematic naturalist, was very strong in me. It was clearly innate. None of my sisters or brother had this taste.
Darwin, Autobiography
Cross the Welsh Bridge out of town, go up the hill
on Frankwell Street and you'll see, above the Severn,
brick pillars with the sandy bloom of an ageing dog.
Around the back, Father's surgery and waiting-room.
Outside, the Stable Yard: hay chutes, a piggery and toolshed.
Lower down, a bothy on the river bank
where plates of jagged ice, harvested in winter from the river,
lean one against the other. A dairy, where these blocks are dragged
to cool the milk and cream. The Quarry Pool
where he fishes for newts and tadpoles.
Collecting: to assert control
over what's unbearable. To gather and to list.
'Stones, coins, franks, insects, minerals and shells.'
Collect yourself: to smother what you feel,
recall to order, summon in one place;
making, like Orpheus, a system against loss.
(Editor's note: Darwin's father was an affluent doctor. The estate of his house, The Mount, bordered the River Severn)
Making faces may have been adaptive
Apparently, faces of fear and disgust are polar opposite expressions and seemed to have been the first few facial expressions to have evolved. They may have evolved for the purpose of moderating sensations and external physiological experiences in the environment. In an article in Nature magazine in 2008, researchers state that fear can be used to monitor and scrutinize the surrounding - flared nostrils and widened, terrified eyes may be able to take in more of the environment in both the visual and olfactory sense. In contrast, when feeling disgust, the nose crinkles naturally to impede nasty odors that may be harmful. Eyes squint so that less of a disgusting scene is taken in. This is very interesting to me as I never thought of fear and disgust as polar opposites; they often come hand-in-hand in everyday expression that I have assumed they complemented each other. There was also a contrast in air intake, which increased for fear and decreased for disgust. Air intake was interestingly measured with MRI. MRI images show that fear opens nasal passages while disgust closes them!
The above study was performed by Susskind and Anderson at the University of Toronto. They had participants feign expressions of fear and disgust to gauge relative eye opening sizes and visual fields. However, artificially and forcibly expressing these emotions for this experiment may not be the most ecologically valid approach. It's difficult to disentangle real fear/disgust being voluntarily experienced from the participants simply putting on an expression that they have been encultured/conditioned to produce as corresponding to those emotions.
This idea is definitely not new as Darwin himself discussed in the Expression of Emotions in Man and Animal that facial expressions actually were like shields to protect the person. They were not simply used for communication and conversation purposes. Modern researchers second this idea - expressions did not originate from language as expressions are not as variable as language, i.e. there are different words for anger but the expression of anger is shared. However, expression as language also helped with survival purposes as understanding one another's facial expressions likely cohered social groups and implicit communication could be exchanged. For instance, understanding and copying a terrified gaze on someone else's face can instigate another individual to do the same and become more vigilant of his/her surroundings to ensure survival. Then I wonder if different extents of making a face, i.e. if you made a huge facial expression of disgust, proffers any advantages... Also, I wonder why there would a need to copy expressions and why that's such a prevalent theme in adaptation when physiologically and physically, we're all more or less equally equipped to make the same expressions? If this ability is hard-wired to some extent, wouldn't it be somewhat out of voluntary and conscious control and arise spontaneously?
-Bonnie Chien
http://www.sciencenews.org/view/generic/id/33290/title/Where_funny_faces_come_from
The above study was performed by Susskind and Anderson at the University of Toronto. They had participants feign expressions of fear and disgust to gauge relative eye opening sizes and visual fields. However, artificially and forcibly expressing these emotions for this experiment may not be the most ecologically valid approach. It's difficult to disentangle real fear/disgust being voluntarily experienced from the participants simply putting on an expression that they have been encultured/conditioned to produce as corresponding to those emotions.
This idea is definitely not new as Darwin himself discussed in the Expression of Emotions in Man and Animal that facial expressions actually were like shields to protect the person. They were not simply used for communication and conversation purposes. Modern researchers second this idea - expressions did not originate from language as expressions are not as variable as language, i.e. there are different words for anger but the expression of anger is shared. However, expression as language also helped with survival purposes as understanding one another's facial expressions likely cohered social groups and implicit communication could be exchanged. For instance, understanding and copying a terrified gaze on someone else's face can instigate another individual to do the same and become more vigilant of his/her surroundings to ensure survival. Then I wonder if different extents of making a face, i.e. if you made a huge facial expression of disgust, proffers any advantages... Also, I wonder why there would a need to copy expressions and why that's such a prevalent theme in adaptation when physiologically and physically, we're all more or less equally equipped to make the same expressions? If this ability is hard-wired to some extent, wouldn't it be somewhat out of voluntary and conscious control and arise spontaneously?
-Bonnie Chien
http://www.sciencenews.org/view/generic/id/33290/title/Where_funny_faces_come_from
Book Review: Spent: Sex, Evolution and the Secrets of Consumerism by Geoffrey Miller & William Heinemann
Darwin's birthday coincides with the premier of the film, Confessions of a Shop-a-holic. While this might appear to be two mutually independent events, authors Geoffrey Miller and Willian Heinemann beg to differ. Shopping, they attest, is an trait we have acquired in our evolution and plays significantly in out current methods of selecting the ideal partner. They tie together evolution and our developed consumer spending habits to assert that the latter "“makes us forget our natural adaptations for showing off desirable fitness-related traits." In other words, money has the ability override our sexual selection abilities by granting us the ability to purchase desirable traits! Luckily, Miller et. al. continues their theory by asserting, luckily, we --luckily-- have evolved concomitantly since the introduction of consumerism and now, we have the innate ability to detect these purchased and fake traits and override their appeal! He uses these theories, loosely based on Darwin's sexual/social selection findings, to explain the impact of consumerism in our lives.
Additionally, he advances his findings by using them to explain routine and normal consumer decisions. For instance, he assert that often, extra features on an consumer electronic device are not purchased for their technical use, but for their abilities to provide the consumer with a way to discuss those features in ways that makes them appear more intelligent.
In my opinion, the book is mostly geared towards marketers and others in the business industry who aim to attract others' affinity for a living. Those looking for a scientifically sound explanation of how evolution and consumerism evolved together and fit into our modern lives should look elsewhere. There's hardly any attempt at empirically proving the assertions in the book. It's quite loony at times. However, it was still highly interesting to see how Darwin's findings can be incorporated into out daily, modern lives. "Spent" was also a fun and entertaining read, albeit I remind you it wasn't super educational, read. I recommend it for the curious, the stags, and the marketers.
-Teresa
Additionally, he advances his findings by using them to explain routine and normal consumer decisions. For instance, he assert that often, extra features on an consumer electronic device are not purchased for their technical use, but for their abilities to provide the consumer with a way to discuss those features in ways that makes them appear more intelligent.
In my opinion, the book is mostly geared towards marketers and others in the business industry who aim to attract others' affinity for a living. Those looking for a scientifically sound explanation of how evolution and consumerism evolved together and fit into our modern lives should look elsewhere. There's hardly any attempt at empirically proving the assertions in the book. It's quite loony at times. However, it was still highly interesting to see how Darwin's findings can be incorporated into out daily, modern lives. "Spent" was also a fun and entertaining read, albeit I remind you it wasn't super educational, read. I recommend it for the curious, the stags, and the marketers.
-Teresa
Researchers model super-strong fish jaws
A new study reveals that Dunkleosteus terreli, a schoolbus-sized ancient fish, had one of the most powerful bites in history: its jaws exerted maximum forces of about 7,495 newtons, or half the weight of a VW beetle.
Today, only the great white shark and a few types of alligators beat out the Dunkleosteus for bite-force. Dunkleosteus is a better biter than any other reported fish species, as well as modern mammals like the spotted hyena, whose jaws are built to cut through bone. (T-rexes, according to models, still had a stronger bite than Dunkleosteus.)
Dunkleosteus is a species of placoderm—giant armored fish that lived during the Devonian period (415-360 mya). Placoderms provide an early and relatively well-preserved example of vertebrate jaw development, so studying their function may teach us more about the evolution of vertebrate feeding, in general.
Researchers based their computerized model of a Dunkleosteus jaw on a simple four-bar linkage mechanism—essentially four rigid rods connected in a square—combined with “landmark morphological data” (details from the actual fossils?). By analyzing their model’s skull and jaw movements, they were able to draw conclusions about the giant fish’s jaw speed, rotation, and force.
They found that Dunkleosteus opened its mouth by moving both its upper and lower jaw (most animals only drop their lower jaw). They also discovered that the fish had unusually high jaw-opening speed, and (as mentioned above) an incredibly strong bite.
This combination of characteristics means that Dunkleosteus could “potentially eat anything in its ecosystem, including other placoderms.”
Aside from being a badass animal with an awesome name, my interest in biodesign makes Dunkleosteus especially exciting to me. A fundamental problem in the world of human engineering is how to generate big forces efficiently. Animals, and natural selection, deal with the same issue. I think that a huge amount can be learned from these kinds of models, and from a better understanding of how natural selection has, over millions of years, “approached” the problems we deal with as humans today.
Read the "science news" article here; the abstract it references here; or an open-access article by the same authors here.
-Anne
Today, only the great white shark and a few types of alligators beat out the Dunkleosteus for bite-force. Dunkleosteus is a better biter than any other reported fish species, as well as modern mammals like the spotted hyena, whose jaws are built to cut through bone. (T-rexes, according to models, still had a stronger bite than Dunkleosteus.)
Dunkleosteus is a species of placoderm—giant armored fish that lived during the Devonian period (415-360 mya). Placoderms provide an early and relatively well-preserved example of vertebrate jaw development, so studying their function may teach us more about the evolution of vertebrate feeding, in general.
Researchers based their computerized model of a Dunkleosteus jaw on a simple four-bar linkage mechanism—essentially four rigid rods connected in a square—combined with “landmark morphological data” (details from the actual fossils?). By analyzing their model’s skull and jaw movements, they were able to draw conclusions about the giant fish’s jaw speed, rotation, and force.
They found that Dunkleosteus opened its mouth by moving both its upper and lower jaw (most animals only drop their lower jaw). They also discovered that the fish had unusually high jaw-opening speed, and (as mentioned above) an incredibly strong bite.
This combination of characteristics means that Dunkleosteus could “potentially eat anything in its ecosystem, including other placoderms.”
Aside from being a badass animal with an awesome name, my interest in biodesign makes Dunkleosteus especially exciting to me. A fundamental problem in the world of human engineering is how to generate big forces efficiently. Animals, and natural selection, deal with the same issue. I think that a huge amount can be learned from these kinds of models, and from a better understanding of how natural selection has, over millions of years, “approached” the problems we deal with as humans today.
Read the "science news" article here; the abstract it references here; or an open-access article by the same authors here.
-Anne
Sunday, May 24, 2009
Human Impacts on Species Evolution
I find this article to be particularly interesting after reading The Origin.
New York Times writer Cornelia Dean briefly describes human involvement in the domestication and evolution of certain species of animals. Then she goes on to explain a “growing environmental problem – the way human predation is causing target species to evolve at younger ages and smaller sizes, their short-term benefit but to the long-term harm of the species.” Humans “impose mortality” at certain points during the life cycle on countless species of animals. With the development of fire, hunting, agriculture and development, humans have mastered the alteration of the natural landscape. J. Stanley Cobb, a lobster expert from the University of Rhode Island, articulates: “if we believe that natural selection has shaped the life history characteristics of a species, then we have to believe that a different mortality regime will affect life history.”
Examples:
With global warming, plants in the Rocky Mountains are relocating to higher – cooler – elevations.
Some trees, shrubs and flowers in New England are blooming weeks earlier than they did a century ago.
The inhabitants of the tide pools of Monterey Bay is changing as temperatures rise and certain plants and animals adapt – or fail to adapt – to the warmer waters.
Over fished cod have started reproducing at younger ages and smaller sizes. This type of behavior is also increasingly found in a range of other species: bighorn sheep, caribou, and ginseng plants.
This adaptation increases the likelihood of reproducing before being killed, but the change can actually be harmful in the long run. An environmental scientist at the University of Calgary, Paul Paquet explains: “It’s forced evolution. It’s not working to their advantage.”
How are some policy-makers responding to this human-induced evolution? In the West, some environmentalists are attempting to maintain the genetic diversity of deer, bears, and other animals through the use of tunnels and overpasses that allow them to “access their full range, even if it is now divided by highways.”
I don’t necessarily think that we should build tunnels to preserve the genetic diversity of deer, but it’s interesting to consider the impact that humans have on the evolution of other creatures.
Read the full article here.
-Lauren
New York Times writer Cornelia Dean briefly describes human involvement in the domestication and evolution of certain species of animals. Then she goes on to explain a “growing environmental problem – the way human predation is causing target species to evolve at younger ages and smaller sizes, their short-term benefit but to the long-term harm of the species.” Humans “impose mortality” at certain points during the life cycle on countless species of animals. With the development of fire, hunting, agriculture and development, humans have mastered the alteration of the natural landscape. J. Stanley Cobb, a lobster expert from the University of Rhode Island, articulates: “if we believe that natural selection has shaped the life history characteristics of a species, then we have to believe that a different mortality regime will affect life history.”
Examples:
With global warming, plants in the Rocky Mountains are relocating to higher – cooler – elevations.
Some trees, shrubs and flowers in New England are blooming weeks earlier than they did a century ago.
The inhabitants of the tide pools of Monterey Bay is changing as temperatures rise and certain plants and animals adapt – or fail to adapt – to the warmer waters.
Over fished cod have started reproducing at younger ages and smaller sizes. This type of behavior is also increasingly found in a range of other species: bighorn sheep, caribou, and ginseng plants.
This adaptation increases the likelihood of reproducing before being killed, but the change can actually be harmful in the long run. An environmental scientist at the University of Calgary, Paul Paquet explains: “It’s forced evolution. It’s not working to their advantage.”
How are some policy-makers responding to this human-induced evolution? In the West, some environmentalists are attempting to maintain the genetic diversity of deer, bears, and other animals through the use of tunnels and overpasses that allow them to “access their full range, even if it is now divided by highways.”
I don’t necessarily think that we should build tunnels to preserve the genetic diversity of deer, but it’s interesting to consider the impact that humans have on the evolution of other creatures.
Read the full article here.
-Lauren
Saturday, May 23, 2009
Overdue Library Books?
Hopefully not this overdue! Peter Dizikes reports that the Boston Public Library was stunned when Julie Geissler turned up at their doorstep with a first-edition copy of Darwin's On the Origin of Species. The book, overdue by over eighty years, is one of three first-edition copies owned by the Boston Public Library. (According to Janet Browne, around 1,100 first-edition copies were printed in total.) Dizikes speculates that the library was able to acquire multiple copies because the book was intended for general sale to the public, rather than limited to academicians. Although none of the Boston Library copies have acquisition records, Dizikes traces their inscriptions back to Robert Gordon Tatham, a respected London doctor, and Charles Lacaita, a member of the British Parliament and botanist. The book returned by Geissler contains no information about its origin.
Ben Picozzi
Ben Picozzi
Wednesday, May 20, 2009
Discerning the origin of flowers
The unexpected explosion of flowering plant species 130 million years has been a mystery to scientists, Darwin included. Researchers at the University of Florida have published findings from a study on the original gene regulatory program that produced the first flower on all flowering plant's common ancestor. They studied the genetics of two very different species of angiosperms, Arabidopsis thaliana, a common flowering plant used in plant genetics research, and Persea americana, a primitive flowering plant; their aim was to see if the genetic circuitry that gave rise to each species' flower had any differences. The results found that the Persea's flowers contained genetic relics, gene regulation instructions that would facilitate the transformation of cones into flowers.
This discovery lends further insight into the sudden onset of angiosperms in a previously gymnosperm-dominated world, suggesting a mechanism for how angiosperms could have directly descended from gymnosperms. Further research into this genetic circutry could assist scientists in manipulating the traits of plants so as to make them more resistant to drought or disease.
-Andrew Plan
This discovery lends further insight into the sudden onset of angiosperms in a previously gymnosperm-dominated world, suggesting a mechanism for how angiosperms could have directly descended from gymnosperms. Further research into this genetic circutry could assist scientists in manipulating the traits of plants so as to make them more resistant to drought or disease.
-Andrew Plan
Remember the Audio Guide at Down?
Apparently, Ruth Padel's poetry is good enough to land her a professorship. Padel, Darwin's great-great-granddaughter was elected the first female professor of poetry at Oxford univeristy after then-frontrunner, Darek Walcott withdrew from the competition. Quite an accomplishment.
For those who missed the audio guide, you Padel's poetry of Darwin is collected in her recent publication, Darwin: A Life in Poems. The themes of her poetry is drawn directly from Darwin's writings. For example, ""Vegetation he's never seen, and every step a new surprise. / New insects, fluttering about still newer flowers. It has been / for me a glorious day, like giving to a blind man eyes" is derived from Darwin's exclamation that seeing the South American jungle was "like giving to a blind man eyes".
Hopefully, Darwin would have approved!
Ben Picozzi
For those who missed the audio guide, you Padel's poetry of Darwin is collected in her recent publication, Darwin: A Life in Poems. The themes of her poetry is drawn directly from Darwin's writings. For example, ""Vegetation he's never seen, and every step a new surprise. / New insects, fluttering about still newer flowers. It has been / for me a glorious day, like giving to a blind man eyes" is derived from Darwin's exclamation that seeing the South American jungle was "like giving to a blind man eyes".
Hopefully, Darwin would have approved!
Ben Picozzi
Where Darwin Went Wrong
Richard Dawkins talks with Paul Davies at the Origins symposium on a range of relevant topics, including Darwin and the Oxford climate (“I don't get to wear my Hawaiian print shirt at Oxford”). During the talk, Darwin emphasizes the shortcomings in Darwin’s understanding of evolution, notably, his failure to properly understand Mendelian heredity.
In a recent journal article, Jonathan Howard analyzes why Darwin failed to discover Mendel's laws of inheritance. After all, Mendel solved the puzzle from his monastery garden. Why couldn't Darwin? Howard argues that Darwin’s failure resulted from his commitment to the study of qualitative characteristics – height, weight, etc. – which provide a poor starting point for correctly analyzing heredity because their expression is controlled by multiple allelic systems as well as environmental factors.
Consequently, when Darwin published his theory of pangenesis, he completely missed the mark. In The Variation of Animals and Plants Under Domestication (1968), Darwin attributes the expression of phenotypes to the accumulation of “pangenes” from all over the body in the germ cells of the parents, which are then blended together during conception. On Darwin’s view, this accumulation is a continuous process, which constantly updates rather than a discontinuous one – hence, his notorious acceptance of the Lamarkian belief in the inheritance of acquired traits.
While Howard’s argument is interesting and potentially plausible, he downplays the importance of Darwin’s research motivations, namely, his overwhelming interest in the natural selection. In fairness, Howard does make moves towards this conclusion. He notes that in The Origin Darwin does rely on principles of heredity for his argument, for example, the recovery of the wild type from two, seemingly distinct recessive mutants, however, he brackets the question of the principles of heredity since his interest lies solely in proposing “atavism” as evidence for evolution. Nevertheless, Howard quickly passes over these examples as support for his thesis.
Cf. Howard et al. “Why Didn't Darwin Discover Mendel's Laws?”Journal of Biology, 2009; 8 (2): 15
Ben Picozzi
In a recent journal article, Jonathan Howard analyzes why Darwin failed to discover Mendel's laws of inheritance. After all, Mendel solved the puzzle from his monastery garden. Why couldn't Darwin? Howard argues that Darwin’s failure resulted from his commitment to the study of qualitative characteristics – height, weight, etc. – which provide a poor starting point for correctly analyzing heredity because their expression is controlled by multiple allelic systems as well as environmental factors.
Consequently, when Darwin published his theory of pangenesis, he completely missed the mark. In The Variation of Animals and Plants Under Domestication (1968), Darwin attributes the expression of phenotypes to the accumulation of “pangenes” from all over the body in the germ cells of the parents, which are then blended together during conception. On Darwin’s view, this accumulation is a continuous process, which constantly updates rather than a discontinuous one – hence, his notorious acceptance of the Lamarkian belief in the inheritance of acquired traits.
While Howard’s argument is interesting and potentially plausible, he downplays the importance of Darwin’s research motivations, namely, his overwhelming interest in the natural selection. In fairness, Howard does make moves towards this conclusion. He notes that in The Origin Darwin does rely on principles of heredity for his argument, for example, the recovery of the wild type from two, seemingly distinct recessive mutants, however, he brackets the question of the principles of heredity since his interest lies solely in proposing “atavism” as evidence for evolution. Nevertheless, Howard quickly passes over these examples as support for his thesis.
Cf. Howard et al. “Why Didn't Darwin Discover Mendel's Laws?”Journal of Biology, 2009; 8 (2): 15
Ben Picozzi
Distant Relative of Primates and Man?
NY Times: Scientists have recently found a highly preserved skeleton of a creature supposed by some to be the key to early primate evolution. "Darwinius masillae" or "Ida" is a 47-million-year old animal that is "about the size of a small cat," and "has four legs and a long tail." The level of detail experts have been able to glean from her skeleton is astonishing; we can infer her diet, which was primarily composed of leaves and fruit in a rainforest environment. Jens Franzen of the Senckenberg Research Institute in Frankfurt, Germany believes "Ida" is like a distant aunt, and can tell us much about what anthropoid ancestors looked like a long time ago.
While some are hailing the discovery as a breakthrough in early primate evolution, some are a bit more skeptical. K. Christopher Beard of the Carnegie Museum of Natural History in Pittsburgh made the following remark: ''I actually don't think it's terribly close to the common ancestral line of monkeys, apes and people. I would say it's about as far away as you can get from that line and still be a primate." Rather than a long-ago aunt, Beard says, "I would say it's more like a third cousin twice removed."
If you're interested in learning more about this creature, there will be an upcoming special on the History Channel featuring "Ida."
-Alyssa
While some are hailing the discovery as a breakthrough in early primate evolution, some are a bit more skeptical. K. Christopher Beard of the Carnegie Museum of Natural History in Pittsburgh made the following remark: ''I actually don't think it's terribly close to the common ancestral line of monkeys, apes and people. I would say it's about as far away as you can get from that line and still be a primate." Rather than a long-ago aunt, Beard says, "I would say it's more like a third cousin twice removed."
If you're interested in learning more about this creature, there will be an upcoming special on the History Channel featuring "Ida."
-Alyssa
Monday, May 18, 2009
In Search For the Next Darwin
-C. Paula de los Angeles
Wonder why we saw so many school children while we are at the Kew?
Kew Gardens is in search for the next Charles Darwin and has created The Great Plant Hunt in collaboration with the Wellcome Trust to get primary school children excited about nature.
To commemorate Darwin's bicentennial birthday, the Kew is sending the UK’s 22,000 state maintained primary schools "a treasure chest full of free resources to be used in the classroom, online and in the great outdoors".
Wow!
http://www.kew.org/press/great_plant_hunt.html
Wonder why we saw so many school children while we are at the Kew?
Kew Gardens is in search for the next Charles Darwin and has created The Great Plant Hunt in collaboration with the Wellcome Trust to get primary school children excited about nature.
To commemorate Darwin's bicentennial birthday, the Kew is sending the UK’s 22,000 state maintained primary schools "a treasure chest full of free resources to be used in the classroom, online and in the great outdoors".
Wow!
http://www.kew.org/press/great_plant_hunt.html
Human Evolution and Costly Signaling
-C. Paula de los Angeles
Evolutionary psychologist, Dr. Miller believes that humans employ "costly signaling" such as having a Harvard degree or a BMW just as a peacock may use his ornate tail, as outlined in his new book: “Spent: Sex, Evolution and Consumer Behavior.”
While some may argue there are other reasons for attending Harvard or owning a BMW or iPhone, Miller argues that, ultimately, they are for signaling one's fitness, a way to demonstrate intelligence or one of the Big Five personality traits: openness, conscientiousness, agreeableness, stability and extraversion.
Interesting quote: “We evolved as social primates who hardly ever encountered strangers in prehistory,” Dr. Miller says. “So we instinctively treat all strangers as if they’re potential mates or friends or enemies. But your happiness and survival today don’t depend on your relationships with strangers. It doesn’t matter whether you get a nanosecond of deference from a shopkeeper or a stranger in an airport.”
Question: How does sexual selection work at the human level?
NYTimes article: http://www.nytimes.com/2009/05/19/science/19tier.html?ref=science
Evolutionary psychologist, Dr. Miller believes that humans employ "costly signaling" such as having a Harvard degree or a BMW just as a peacock may use his ornate tail, as outlined in his new book: “Spent: Sex, Evolution and Consumer Behavior.”
While some may argue there are other reasons for attending Harvard or owning a BMW or iPhone, Miller argues that, ultimately, they are for signaling one's fitness, a way to demonstrate intelligence or one of the Big Five personality traits: openness, conscientiousness, agreeableness, stability and extraversion.
Interesting quote: “We evolved as social primates who hardly ever encountered strangers in prehistory,” Dr. Miller says. “So we instinctively treat all strangers as if they’re potential mates or friends or enemies. But your happiness and survival today don’t depend on your relationships with strangers. It doesn’t matter whether you get a nanosecond of deference from a shopkeeper or a stranger in an airport.”
Question: How does sexual selection work at the human level?
NYTimes article: http://www.nytimes.com/2009/05/19/science/19tier.html?ref=science
Cooking is responsible for human evolution?
Harvard primatologist and anthropologist Richard Wrangham’s new book will hit bookshelves on May 25. In Catching Fire: How Cooking Made Us Human, Wrangham theorizes that the evolutionary success of humans was originally the result of mastering fire and using it to cook. In the past, scientists have said that tools and meat consumption lead to the development of modern man. According to Wrangham, our ancestors began cooking about 1.8 million years ago, and this lead to a more nutritious diet that required less eating time. Cooking also lead to a rich diet that shaped the human body, and lead to the development of the large brain.
I like this theory – it seems logical enough, although I’d have to read the book for myself to determine whether Wrangham makes a sound argument. I don’t believe there is archaeological proof that humans made fires 1.8 million years ago, and this is troubling because it seems like Wrangham’s argument requires that we assume this to be true. The absence of evidence does not disprove Wrangham’s theory, but it makes me consider his point of view with a critical eye an cautious mind.
-Lauren
I like this theory – it seems logical enough, although I’d have to read the book for myself to determine whether Wrangham makes a sound argument. I don’t believe there is archaeological proof that humans made fires 1.8 million years ago, and this is troubling because it seems like Wrangham’s argument requires that we assume this to be true. The absence of evidence does not disprove Wrangham’s theory, but it makes me consider his point of view with a critical eye an cautious mind.
-Lauren
On Science Jargon
I was reminded of our conversations last Thursday by the first few paragraphs of this article. It discusses the various science jargon used to describe research efforts, and the interesting arguments that arise from the uses of semantics and the importance of word choice in scientific literature and the scientific community.
http://www.mysanantonio.com/life/45270017.html
Enjoy!
Kaitlyn
http://www.mysanantonio.com/life/45270017.html
Enjoy!
Kaitlyn
Sunday, May 17, 2009
Digging for Darwin-NY Times Essay
-C. Paula de los Angeles
A New Hampshire resident returned a first edition of On the Origin of Species to the Boston Public Library, overdue for 80 years!
Only around 1,100 first editions were published.
Those who have reported owning this edition include: "an intellectually curious member of the Victorian bourgeoisie, the unusual family story of an Italian exile in England, the agony of the Great War, the rise of American wealth and collecting, a Rhode Island scholar’s quiet bibliophilia, and a New Hampshire woman’s matter-of-fact generosity".
http://www.nytimes.com/2009/05/17/books/review/Dizikes-t.html?pagewanted=1&_r=1&em
A New Hampshire resident returned a first edition of On the Origin of Species to the Boston Public Library, overdue for 80 years!
Only around 1,100 first editions were published.
Those who have reported owning this edition include: "an intellectually curious member of the Victorian bourgeoisie, the unusual family story of an Italian exile in England, the agony of the Great War, the rise of American wealth and collecting, a Rhode Island scholar’s quiet bibliophilia, and a New Hampshire woman’s matter-of-fact generosity".
http://www.nytimes.com/2009/05/17/books/review/Dizikes-t.html?pagewanted=1&_r=1&em
We ate the cheddar man?!
An article in the Journal of Anthropological Sciences, reported on in the UK Guardian, argues that Neanderthals may have gone extinct because they were eaten by modern humans.
The hypothesis is based on discovery of a Neanderthal jawbone that appears to have been cut in the same way as the bones of deer that were consumed by early humans.
"Neanderthals met a violent end at our hands and in some cases we ate them…for years, people have tried to hide away from the evidence of cannibalism, but I think we have to accept it took place," said the (maybe overenthusiastic?) Fernardo Rozzi of Paris's Centre National de la Récherche Scientifique.
The discovery will certainly be met with much opposition from scientists with other (less-violent, but less interesting) theories—ie, Neanderthals were more susceptible to climate change, or couldn’t compete for food as effectively as humans.
mmm, cheddar men.
Anne
The hypothesis is based on discovery of a Neanderthal jawbone that appears to have been cut in the same way as the bones of deer that were consumed by early humans.
"Neanderthals met a violent end at our hands and in some cases we ate them…for years, people have tried to hide away from the evidence of cannibalism, but I think we have to accept it took place," said the (maybe overenthusiastic?) Fernardo Rozzi of Paris's Centre National de la Récherche Scientifique.
The discovery will certainly be met with much opposition from scientists with other (less-violent, but less interesting) theories—ie, Neanderthals were more susceptible to climate change, or couldn’t compete for food as effectively as humans.
mmm, cheddar men.
Anne
2 links...
The New York Times's science section currently has an interactive(-ish) feature on the Origin of Species, with overviews of Darwin's different arguments and commentary by current scientists. Could be a good resource for presentations?
Here's the link to the 200th anniversary debate between Dawkins and former Bishop of Oxford Richard Harries--I think meant to re-create the famous Huxley/Wilberforce debate, but ends up being a (civil) discussion about the roles of religion and evolution. Kind of long (1 hr) but interesting!
Anne
Here's the link to the 200th anniversary debate between Dawkins and former Bishop of Oxford Richard Harries--I think meant to re-create the famous Huxley/Wilberforce debate, but ends up being a (civil) discussion about the roles of religion and evolution. Kind of long (1 hr) but interesting!
Anne
Primate-lemurs!
A May 16 New York Times article and a May 15 Wall Street Journal article reported on the discovery of fossilized remains from a “primate-lemur,” living 47 million years ago during the Eocene period.
Researchers believe it’s a candidate for placement in the human ancestral line. Although the fossil is lemur-like in most ways, it lacks several key features that monkeys, apes, and humans also lack--like a “tooth comb” (a tooth for fur-grooming) and a grooming claw.
During the Eocene period, there were two ape-like groups—tarsidae (ancestors of the tarsier) and adapidae (ancestors of the lemur). We’re not sure which of these groups gave rise to monkeys, apes, and humans. This discovery lends support to the less-popular belief that our ancestors were adapidae, rather than tarsidae.
The fossil, found in the Messel Shale Pit in Germany, is incredibly well-preserved: its stomach contained an identifiable meal (of fruit and leaves), and it was possible to see impressions of fur and soft body tissue.
That site has been the source of other well-preserved fossils, and made me wonder about the environmental conditions that make preservation possible. How rare are they? How many remains have we likely lost due to poor conditions for fossilization? I imagine we might have an entirely different picture of human history right now if our pattern of fossil discovery had been different.
The fossil is quickly becoming a star of the evolutionary world: it’s getting news conferences, a History Channel feature, a display at the American Museum of Natural History, and a book. This made me think about the economics of fossil-discovery, and the hype surrounding such a popular scientific topic. As Dawkins points out in “The Blind Watchmaker,” people are attracted to evolution (rather than, say, quantum mechanics) maybe because it appears so simple and accessible. To what degree is that accessibility exploited in the hype surrounding new fossil discoveries?
Anne
Researchers believe it’s a candidate for placement in the human ancestral line. Although the fossil is lemur-like in most ways, it lacks several key features that monkeys, apes, and humans also lack--like a “tooth comb” (a tooth for fur-grooming) and a grooming claw.
During the Eocene period, there were two ape-like groups—tarsidae (ancestors of the tarsier) and adapidae (ancestors of the lemur). We’re not sure which of these groups gave rise to monkeys, apes, and humans. This discovery lends support to the less-popular belief that our ancestors were adapidae, rather than tarsidae.
The fossil, found in the Messel Shale Pit in Germany, is incredibly well-preserved: its stomach contained an identifiable meal (of fruit and leaves), and it was possible to see impressions of fur and soft body tissue.
That site has been the source of other well-preserved fossils, and made me wonder about the environmental conditions that make preservation possible. How rare are they? How many remains have we likely lost due to poor conditions for fossilization? I imagine we might have an entirely different picture of human history right now if our pattern of fossil discovery had been different.
The fossil is quickly becoming a star of the evolutionary world: it’s getting news conferences, a History Channel feature, a display at the American Museum of Natural History, and a book. This made me think about the economics of fossil-discovery, and the hype surrounding such a popular scientific topic. As Dawkins points out in “The Blind Watchmaker,” people are attracted to evolution (rather than, say, quantum mechanics) maybe because it appears so simple and accessible. To what degree is that accessibility exploited in the hype surrounding new fossil discoveries?
Anne
Saturday, May 16, 2009
Human Nature Commonalities
Rather than a hot news, this is more of a reflective thought...
We are all familiar with Paul Ekman's study of going around the world to primitive human communities and asking them to identify facial expressions of emotion. Although he sought to prove Darwin wrong that "the chief [emotional] expressions exhibited by man are the same throughout the world", he actually came back acceding that Darwin had a point. Other similarities across human civilizations include the cross-cultural tendencies to form communities, pay attention to kinship relationships, use language to communicate, socialize, and even adorn their bodies! Even more peculiar is that many languages use a word similar in meaning to "small person" to describe the iris (as English does too). Perhaps this relates to the shared belief that the pupil offers a small portal to the viewer of his/her reflection, hence "small person."
I am rather a appreciator of evolutionary psychology and following from my weekly observations and book review trying to instill hope in the field, I've found a niche for evolutionary psychology here in universal human traits!
So yes there are numerous traits that appear to be universal in humans as identified by researchers such as Paul Ekman, Donald Brown (who wrote "Human Universals"). However, anthropologists and evolutionary psychologists are now looking into the oddities and differences in human nature rather than the universals to shed light on the universals! Specifically, researchers have looked at cultural malleability in addition to genetic, biological predispositions. For instance, although even chimps have been shown to respond to the ultimatum game similarly as humans; i.e. they will perform 'altruistic punishment' and punish free-riders who parasitize the efforts of others, not all human societies in fact behave like this to the same degree. Many of our current misconceptions and overestimations of universality come from WEIRD subjects (I like this acronym!): westernized, educated, industrialized, rich and democratic.
So, I think the efforts of these evolutionary psychologists can be directed towards answering some of the questions we discussed in class on Wed, about whether science and religion can address similar issues such as morality. Jonathan Haidt, of the University of Virginia in Charlottesville and Craig Joseph, of Northwestern University in Evanston, Illinois argue that evolution has favored human consideration of five social/moral issues: "fairness and justice; avoiding harm to and caring for others; in-group loyalty; social hierarchy and respect for authority; and the domain of divinity and purity, both bodily and spiritual." As the scientific underpinnings of these weighted values become clearer, I suppose science will be able to justify moral fortitude in humans without recourse to religion propounding God's grace in instilling this capacity based on his own image in human beings. Perhaps science will be able to explain the mechanism of our ability to absorb and enact ever-changing cultural norms and reconcile with religion that purports an external authority (god) serving as our moral compass. Well, maybe our cultural environment is that moral compass.
-Bonnie Chien
http://www.nature.com/news/2009/090211/full/457780a.html
We are all familiar with Paul Ekman's study of going around the world to primitive human communities and asking them to identify facial expressions of emotion. Although he sought to prove Darwin wrong that "the chief [emotional] expressions exhibited by man are the same throughout the world", he actually came back acceding that Darwin had a point. Other similarities across human civilizations include the cross-cultural tendencies to form communities, pay attention to kinship relationships, use language to communicate, socialize, and even adorn their bodies! Even more peculiar is that many languages use a word similar in meaning to "small person" to describe the iris (as English does too). Perhaps this relates to the shared belief that the pupil offers a small portal to the viewer of his/her reflection, hence "small person."
I am rather a appreciator of evolutionary psychology and following from my weekly observations and book review trying to instill hope in the field, I've found a niche for evolutionary psychology here in universal human traits!
So yes there are numerous traits that appear to be universal in humans as identified by researchers such as Paul Ekman, Donald Brown (who wrote "Human Universals"). However, anthropologists and evolutionary psychologists are now looking into the oddities and differences in human nature rather than the universals to shed light on the universals! Specifically, researchers have looked at cultural malleability in addition to genetic, biological predispositions. For instance, although even chimps have been shown to respond to the ultimatum game similarly as humans; i.e. they will perform 'altruistic punishment' and punish free-riders who parasitize the efforts of others, not all human societies in fact behave like this to the same degree. Many of our current misconceptions and overestimations of universality come from WEIRD subjects (I like this acronym!): westernized, educated, industrialized, rich and democratic.
So, I think the efforts of these evolutionary psychologists can be directed towards answering some of the questions we discussed in class on Wed, about whether science and religion can address similar issues such as morality. Jonathan Haidt, of the University of Virginia in Charlottesville and Craig Joseph, of Northwestern University in Evanston, Illinois argue that evolution has favored human consideration of five social/moral issues: "fairness and justice; avoiding harm to and caring for others; in-group loyalty; social hierarchy and respect for authority; and the domain of divinity and purity, both bodily and spiritual." As the scientific underpinnings of these weighted values become clearer, I suppose science will be able to justify moral fortitude in humans without recourse to religion propounding God's grace in instilling this capacity based on his own image in human beings. Perhaps science will be able to explain the mechanism of our ability to absorb and enact ever-changing cultural norms and reconcile with religion that purports an external authority (god) serving as our moral compass. Well, maybe our cultural environment is that moral compass.
-Bonnie Chien
http://www.nature.com/news/2009/090211/full/457780a.html
Wednesday, May 13, 2009
“Energetic Definition of Fitness” and Slower Snails
Traditional definitions of Darwinian fitness emphasize reproductive design and adaptability to environment. The “energetic definition of fitness” emphasizes the distribution of energy among the following activities: food acquisition, metabolism, growth, reproduction, and survival.
Coinciding with the energetic definition of fitness, it appears that evolution is actually slowing snails down, leaving them more energy for other tasks. A BBC News article noted, “It is the first time that evolution has been shown to select for [lower metabolism] in individuals of any species.” Why would nature select for such a trait? According to evolutionary biologist Roberto Nespolo, “Animals that spend less energy [on maintenance] will have more surplus for survival and reproduction.”
Nespolo is currently conducting studies on this topic, and has found “significant directional selection on metabolism.” His team measured standard metabolic rate – the “minimal amount of energy an animal requires to stay alive” – by gauging the amount of carbon dioxide produced by each snail at rest. In a sample of 100 snails, Nespolo found that after seven months, the surviving snails had a 20% lower metabolic rate than those who failed to survive.
Even still, Nespolo’s team must now answer the question: “is having a slow metabolism linked to moving slowly?” The relationship between these two variables is critical to understanding what’s being selected for and snail energetics.
-Alyssa Martin
Coinciding with the energetic definition of fitness, it appears that evolution is actually slowing snails down, leaving them more energy for other tasks. A BBC News article noted, “It is the first time that evolution has been shown to select for [lower metabolism] in individuals of any species.” Why would nature select for such a trait? According to evolutionary biologist Roberto Nespolo, “Animals that spend less energy [on maintenance] will have more surplus for survival and reproduction.”
Nespolo is currently conducting studies on this topic, and has found “significant directional selection on metabolism.” His team measured standard metabolic rate – the “minimal amount of energy an animal requires to stay alive” – by gauging the amount of carbon dioxide produced by each snail at rest. In a sample of 100 snails, Nespolo found that after seven months, the surviving snails had a 20% lower metabolic rate than those who failed to survive.
Even still, Nespolo’s team must now answer the question: “is having a slow metabolism linked to moving slowly?” The relationship between these two variables is critical to understanding what’s being selected for and snail energetics.
-Alyssa Martin
“Missing Links”
How did mammals evolve from sea to land and back again? An article in The San Francisco Chronicle discusses the discoveries that have been made thus far with regard to intermediate sea-land links. One of the preeminent discoveries in this field was the discovery of Tiktaalik roseae:
“Tiktaalik was clearly a fish with scales, gills and fins, but at the ends of its fins were bones suggestive of developing fingers and toes. At the base of its fishlike head were bones found in land animals with flexible necks; its ribs were much more broad and robust than those of today's fish, and its flat head had eyes on top – much like those of crocodiles. Its gills were also modified to rely less on oxygen exchange in the water and showed indirect evidence of an ability to breathe air on land.”
Although Tiktaalik probably never walked, scientists conjecture that he was able to “prop himself up” in push-up style. Nevertheless, Tiktaalik constituted a clear intermediate step in the transition from sea to land. (See Tiktaalik for more discussion.)
After this remarkable finding, paleontologist Charles Carroll called the discovery “one of the most important evolutionary events in the history of vertebrate animals that made it onto the land – perhaps in the history of life itself.”
The article goes on to discuss the naturally selected transition back to sea again, as paleontologist Hans Thewissen recently discovered a “walking and swimming whale” in the waters by Pakistan. This species is thought to be a precursor to today’s whales and dolphins, explaining why these mammals have land-mammal characteristics like “fins, flukes and air-breathing lungs.”
Finally, an intermediate ungulate form – “Indohyus” – has freshly emerged that shares traits with horses, cows, pigs, giraffes, and the hippopotamus. As the Chronicle noted, “It looked like a fox-size deer that swam underwater and lived around the same time as Ambulocetus [the walking and swimming whale].” (See Indohyus for more discussion.)
What do these intermediate links mean in the grand scheme? Do they serve as evidence of steady evolution as opposed to punctuated equilibrium?
-Alyssa Martin
“Tiktaalik was clearly a fish with scales, gills and fins, but at the ends of its fins were bones suggestive of developing fingers and toes. At the base of its fishlike head were bones found in land animals with flexible necks; its ribs were much more broad and robust than those of today's fish, and its flat head had eyes on top – much like those of crocodiles. Its gills were also modified to rely less on oxygen exchange in the water and showed indirect evidence of an ability to breathe air on land.”
Although Tiktaalik probably never walked, scientists conjecture that he was able to “prop himself up” in push-up style. Nevertheless, Tiktaalik constituted a clear intermediate step in the transition from sea to land. (See Tiktaalik for more discussion.)
After this remarkable finding, paleontologist Charles Carroll called the discovery “one of the most important evolutionary events in the history of vertebrate animals that made it onto the land – perhaps in the history of life itself.”
The article goes on to discuss the naturally selected transition back to sea again, as paleontologist Hans Thewissen recently discovered a “walking and swimming whale” in the waters by Pakistan. This species is thought to be a precursor to today’s whales and dolphins, explaining why these mammals have land-mammal characteristics like “fins, flukes and air-breathing lungs.”
Finally, an intermediate ungulate form – “Indohyus” – has freshly emerged that shares traits with horses, cows, pigs, giraffes, and the hippopotamus. As the Chronicle noted, “It looked like a fox-size deer that swam underwater and lived around the same time as Ambulocetus [the walking and swimming whale].” (See Indohyus for more discussion.)
What do these intermediate links mean in the grand scheme? Do they serve as evidence of steady evolution as opposed to punctuated equilibrium?
-Alyssa Martin
Is Technology Darwinian?
Julian Vincent spoke before the Bath Royal Literary and Scientific Institution (BRLSI) which contrasts technological and biological development. Technological progress, he notes, is often characterized as 'technological evolution'. However, Vincent claims, this metaphor is misleading since there are many ways in which technological progress does not follow principles of natural selection. He stresses the 'unguided' nature of nature of Darwinian thought and claims that technology as a human activity is guided. This, in turn, suggests important theoretical differences. For example, it suggests that theories explaining technological development may have greater predictive import than their biological counterparts. (For an interesting discussion of the limitations of various evolutionary theories in generating predictions, see Darwin’s Legacy, reviewed in the document list.)
A review of Vincent's work reveals that he is a leader in the field of biomimetics, that is, the concept of borrowing ideas from nature to further technology. While much of his work consists in specific applications of environmental "designs" – for example, he analyzes arthropod exoskeletons in engineering terms – he has also published on top-level biomimetic theory, including many of the ideas which underlie his speech before the BRLSI. In a 2005 book chapter, he argues that just like biology, technological development takes place on a field of limited resources – the same concept of limited resources in relation to population which motivated Darwin’s theories on the evolutionary mechanism. While technological resources are monetary – as opposed to the energy resources which are addressed by the influential Malthusian political-economic model – the same concepts of inter-organism and intra-organism resource conflicts apply. (Although obviously in the case of technology, the exact nature of selection is determined by the designer, or at least whoever is responsible for the designer’s paycheck.)
Biomimetics seems like an interesting interdisciplinary field, which combines biological insights with engineering and social theory. I encourage anyone who is interested in Darwinian natural selection, but is looking for a more applied subject to look into it as a potential research topic!
Julian Vincent is Professor of Biomimetics and Director of the Centre for Biomimetics and Natural Technologies within the Department of Mechanical Engineering at the University of Bath.
Ben Picozzi
A review of Vincent's work reveals that he is a leader in the field of biomimetics, that is, the concept of borrowing ideas from nature to further technology. While much of his work consists in specific applications of environmental "designs" – for example, he analyzes arthropod exoskeletons in engineering terms – he has also published on top-level biomimetic theory, including many of the ideas which underlie his speech before the BRLSI. In a 2005 book chapter, he argues that just like biology, technological development takes place on a field of limited resources – the same concept of limited resources in relation to population which motivated Darwin’s theories on the evolutionary mechanism. While technological resources are monetary – as opposed to the energy resources which are addressed by the influential Malthusian political-economic model – the same concepts of inter-organism and intra-organism resource conflicts apply. (Although obviously in the case of technology, the exact nature of selection is determined by the designer, or at least whoever is responsible for the designer’s paycheck.)
Biomimetics seems like an interesting interdisciplinary field, which combines biological insights with engineering and social theory. I encourage anyone who is interested in Darwinian natural selection, but is looking for a more applied subject to look into it as a potential research topic!
Julian Vincent is Professor of Biomimetics and Director of the Centre for Biomimetics and Natural Technologies within the Department of Mechanical Engineering at the University of Bath.
Ben Picozzi
Your thoughts about evolution probably influenced by high school
High school is a formative time for all -- you work out your identity, your niche in society, maybe learn a few important life lessons. Depending on what your high school bio class taught, it probably had a big say on your current views on evolution and creationism as well.
A survey conducted by faculty at the College of Biological Sciences at University of Minnesota sought to see if there was a difference in how biology majors viewed evolution and creationism compared to non-biology majors. Two-thirds of the students learned evolution but not creationism in high school, while only 1-2 percent learned creationism but evolution. A large portion of the sample, 29 percent of majors and 21 percent of non-majors, had both evolution and creationism covered in high school. The survey produced surprising results: regardless of major, students who were exposed to creationist perspectives in high school were more likely to adopt them in college, while students exposed to evolution were more receptive to evolution teaching in high school. 72-78% of students exposed to only evolution in high school said that it was scientifically valid, while only 57-59% of students exposed to only creationism said that evolution was scientifically valid.
The authors of the survey also did a review of studies to discern why a large contingent of high school biology teachers still teach creationism. The statistics are astounding: a fourth of biology teachers don't know that is unconstitutional to teach creationism, and another fourth are convinced creationism can be validated with scientific proof.
The article does not mention the views of students who were exposed to both evolution and creationism in high school. Regardless, the findings raise alarm, as high school teachings regarding the origins of man seems to have a lasting impact on students as they move into higher education. The faulty assumptions of biology teachers regarding creationism certainly don't help either. The protocol for teaching the origins of man in high schools is long overdue for a revamping, as no one is getting a complete and accurate story.
article link here: http://www.sciencedaily.com/releases/2009/05/090501123336.htm
-Andrew Plan
A survey conducted by faculty at the College of Biological Sciences at University of Minnesota sought to see if there was a difference in how biology majors viewed evolution and creationism compared to non-biology majors. Two-thirds of the students learned evolution but not creationism in high school, while only 1-2 percent learned creationism but evolution. A large portion of the sample, 29 percent of majors and 21 percent of non-majors, had both evolution and creationism covered in high school. The survey produced surprising results: regardless of major, students who were exposed to creationist perspectives in high school were more likely to adopt them in college, while students exposed to evolution were more receptive to evolution teaching in high school. 72-78% of students exposed to only evolution in high school said that it was scientifically valid, while only 57-59% of students exposed to only creationism said that evolution was scientifically valid.
The authors of the survey also did a review of studies to discern why a large contingent of high school biology teachers still teach creationism. The statistics are astounding: a fourth of biology teachers don't know that is unconstitutional to teach creationism, and another fourth are convinced creationism can be validated with scientific proof.
The article does not mention the views of students who were exposed to both evolution and creationism in high school. Regardless, the findings raise alarm, as high school teachings regarding the origins of man seems to have a lasting impact on students as they move into higher education. The faulty assumptions of biology teachers regarding creationism certainly don't help either. The protocol for teaching the origins of man in high schools is long overdue for a revamping, as no one is getting a complete and accurate story.
article link here: http://www.sciencedaily.com/releases/2009/05/090501123336.htm
-Andrew Plan
Monday, May 11, 2009
Gaps in the fossil record?
Another article on the various attempts to reconcile gaps in the fossil record with Darwin's (and other) theories about gradual evolution:
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/05/11/MNCN16PJI0.DTL
The article gives several examples of various documented evolutionary transitions, including dinosaurs to modern birds and the case of the Himalayan warblers (what a great mystery novel title...).
Enjoy!
Kaitlyn
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2009/05/11/MNCN16PJI0.DTL
The article gives several examples of various documented evolutionary transitions, including dinosaurs to modern birds and the case of the Himalayan warblers (what a great mystery novel title...).
Enjoy!
Kaitlyn
Woodstock + Darwin = Evolution FESTIVAL!
http://www.evolutionfestival.co.uk/
OKay, so this has nothing to do with Darwin but still, the Evolution Fest looks like it's going to be ONE HELL OF A GOOD MUSIC FESTIVAL. I'm thinking about going, I mean, for 9.5 pounds, I get to implicity celebrate Darwin with a day full of explicitly awesome music and festivities.
-Teresa
OKay, so this has nothing to do with Darwin but still, the Evolution Fest looks like it's going to be ONE HELL OF A GOOD MUSIC FESTIVAL. I'm thinking about going, I mean, for 9.5 pounds, I get to implicity celebrate Darwin with a day full of explicitly awesome music and festivities.
-Teresa
Saturday, May 9, 2009
Hobbit Brain explained by Hippo
The hobbit is the common name for Homo floresiensis, a 1-m tall human. Studies of extinct Madagascan hippos by the Natural History Museum may reveal the origins of the hobbit's small cranial capacity. The reason reported is that both hippo and hobbit were island dwellers! The hobbit lived on the Indonesian island of Flores. The team of investigators believe that after the hobbits' ancestor, Homo erectus, became isolated on the island of Madagascar, the hobbit became a dwarf in all senses of the word, physically and mentally... I wonder if small cranial capacity/brain corresponded with decreased cognitive abilities? What's interesting is that this seems to be backward evolution! Rather than proceeding in the direction that eventually gave rise to Homo sapiens, evolution seemed to have taken a "regressive" path. However, this finding fits quite well into my new discovery of the term, ecotype as mentioned in my observations for the week. Perhaps dwarfism allowed better adaptation to the niche in Madagascar. Also, there are plenty of branching events in evolution that may eventually lead to extinction; this serves to remind us that evolution turns a blind eye to so-called "progress". It does not necessarily always choose the most efficient, supposedly adaptive path.
The hobbit's brain is about the size of a chimp brain. The Madagascan hippo may have evolved small brains for its big size for the same reasons as the hobbits. However, the hippo brain used for analysis comes from a 3000-year-old extinct Madagascan hippo. Perhaps the resource limitations on islands and the fact that the brain consumes tons of energy partially explain the adaptation of smaller brains. It would be interesting to investigate any indigenous peoples left in the world who still live in primitive conditions on islands. Perhaps any similarities between their brain size and the hobbit's will better justify the new observation that brain size shrinks with habitation on islands. I wonder if the smaller evolved brain size eventually became a bane for these organisms' survival and thus although being adaptive initially, eventually led to their extinction as bigger brained descendants took over.
Interestingly, domesticated animals also have been reported to have smaller brains than their wild counterparts. However, the decrease in brain size of domestic mammals is not necessarily associated with decrease in body size. Although many confounding variables are present with variations and correlations between brain and body size in domesticated animals (i.e. less stimulation, enrichment in environment can possibly retard brain growth), perhaps domesticated animals in their insular settings can shed some light on any more extreme shrinkage of brain size compared with general dwarfism of the body.
http://www.nature.com/nature/journal/v459/n7243/full/nature07922.html
-Bonnie Chien
The hobbit's brain is about the size of a chimp brain. The Madagascan hippo may have evolved small brains for its big size for the same reasons as the hobbits. However, the hippo brain used for analysis comes from a 3000-year-old extinct Madagascan hippo. Perhaps the resource limitations on islands and the fact that the brain consumes tons of energy partially explain the adaptation of smaller brains. It would be interesting to investigate any indigenous peoples left in the world who still live in primitive conditions on islands. Perhaps any similarities between their brain size and the hobbit's will better justify the new observation that brain size shrinks with habitation on islands. I wonder if the smaller evolved brain size eventually became a bane for these organisms' survival and thus although being adaptive initially, eventually led to their extinction as bigger brained descendants took over.
Interestingly, domesticated animals also have been reported to have smaller brains than their wild counterparts. However, the decrease in brain size of domestic mammals is not necessarily associated with decrease in body size. Although many confounding variables are present with variations and correlations between brain and body size in domesticated animals (i.e. less stimulation, enrichment in environment can possibly retard brain growth), perhaps domesticated animals in their insular settings can shed some light on any more extreme shrinkage of brain size compared with general dwarfism of the body.
http://www.nature.com/nature/journal/v459/n7243/full/nature07922.html
-Bonnie Chien
Wednesday, May 6, 2009
Evolution and Valuing Nature
Paul Bloom, professor of psychology at Yale and the author of Descartes’ Baby argues argues that our psychological responses to nature result from evolutionary pressures. We are all “irrepressible taxonomizers”, he claims, a vestige of our evolutionary past in a world in which organizing the world into categories carried distinct survival benefits. After all, knowing predator from prey can be the difference between an untimely death and a quick meal. If this account is accurate, then Darwin’s own intense devotion to the classification of mussels resulted from the very same evolutionary mechanism which he would later propose!
Bloom further argues that our appreciation of nature – ethical, aesthetic, etc. – results from similarly deep-seated psychological traits, again, evolutionary holdouts. Appropriating E.O. Wilson’s “biophilia” hypothesis, Bloom argues that the vast quantity of empirical evidence suggesting some general human valuation of nature – for example, preference for landscape paintings – suggests some sort of evolutionary cause. (For a critique of Wilson's theories, and evolutionary psychology generally, see Darwin's Legacy.) While Bloom recognizes that the descriptive claim that humans value nature cannot generate any evaluative claim concerning the protection of the natural world, he does argues that the psychological benefits of exposure to nature do support the definition of nature as a good. Hence, although scientific theories cannot make value judgments, they can inform them. Of course, he concedes, “indiscriminate biophilia” makes little sense in an increasingly a-natural world. However, if correct, such psychological theories could generate novel arguments for the preservation of nature.
Interestingly, Bloom draws on the writings of Dennis Dutton, whose theories of art underlie much of his arguments on the psychology of nature. I had the pleasure (no pun intended) of hearing Dutton speak at a lecture at Stanford University earlier this year. While controversial – Dutton made comments were provocative regardless of which side of the analytical/continental philosophical divide one happens to fall, including a shot at a certain Bay Area philosopher – Dutton’s speech was interesting in that it provided a link between evolutionary biology and aesthetics. Roughly, the topic of the talk was the same as the article: the evolutionary nature of aesthetic values. Dutton claims that this nature might ground something like objective aesthetic values, in contrast with conventional views of aesthetics which its values as subjective. I strongly recommend to anyone interested in art and biology to look into this further.
Bloom is currently writing a book on pleasure.
Ben Picozzi
Bloom further argues that our appreciation of nature – ethical, aesthetic, etc. – results from similarly deep-seated psychological traits, again, evolutionary holdouts. Appropriating E.O. Wilson’s “biophilia” hypothesis, Bloom argues that the vast quantity of empirical evidence suggesting some general human valuation of nature – for example, preference for landscape paintings – suggests some sort of evolutionary cause. (For a critique of Wilson's theories, and evolutionary psychology generally, see Darwin's Legacy.) While Bloom recognizes that the descriptive claim that humans value nature cannot generate any evaluative claim concerning the protection of the natural world, he does argues that the psychological benefits of exposure to nature do support the definition of nature as a good. Hence, although scientific theories cannot make value judgments, they can inform them. Of course, he concedes, “indiscriminate biophilia” makes little sense in an increasingly a-natural world. However, if correct, such psychological theories could generate novel arguments for the preservation of nature.
Interestingly, Bloom draws on the writings of Dennis Dutton, whose theories of art underlie much of his arguments on the psychology of nature. I had the pleasure (no pun intended) of hearing Dutton speak at a lecture at Stanford University earlier this year. While controversial – Dutton made comments were provocative regardless of which side of the analytical/continental philosophical divide one happens to fall, including a shot at a certain Bay Area philosopher – Dutton’s speech was interesting in that it provided a link between evolutionary biology and aesthetics. Roughly, the topic of the talk was the same as the article: the evolutionary nature of aesthetic values. Dutton claims that this nature might ground something like objective aesthetic values, in contrast with conventional views of aesthetics which its values as subjective. I strongly recommend to anyone interested in art and biology to look into this further.
Bloom is currently writing a book on pleasure.
Ben Picozzi
Tuesday, May 5, 2009
New genetic revelations regarding the origins of Africans, African Americans
Here's another recent study I came across while reading about different ancestral populations; it's the largest study of the genetic diversity of Africans, spanning four million genotypes identified through the collaborative efforts of African, European, and American researchers.
So what does it tell us? Apparently Africans can be traced back to 14(!) ancestral population clusters, clusters confirmed by their correlation with ethnicity and shared cultural characteristics. The researchers were also able to use the data to approximate the migration of these ancestral populations, identifying southern Africa as the ancestral origin of humans. The data also found African American ancestry to be largely Niger-Kordofanian and European in composition. Even more remarkably, such extrapolations are consonant with established knowledge on the cultural and linguistic diversity in Africa.
Clearly this mother lode of genetic data has much potential beyond tracing population history and migration of African and African-American populations. Imagine the possibilities regarding healthcare -- scientists can use the data to identify what genetic factors specific to Africans and African-Americans increase susceptibility to certain diseases. Knowing the genetic nature of the overwhelming variety among Africans can increase the efficacy of public health initiatives across Africa. It'll be fascinating to see where scientists go with this potent genetic data...
article link here
study link here
-Andrew Plan
So what does it tell us? Apparently Africans can be traced back to 14(!) ancestral population clusters, clusters confirmed by their correlation with ethnicity and shared cultural characteristics. The researchers were also able to use the data to approximate the migration of these ancestral populations, identifying southern Africa as the ancestral origin of humans. The data also found African American ancestry to be largely Niger-Kordofanian and European in composition. Even more remarkably, such extrapolations are consonant with established knowledge on the cultural and linguistic diversity in Africa.
Clearly this mother lode of genetic data has much potential beyond tracing population history and migration of African and African-American populations. Imagine the possibilities regarding healthcare -- scientists can use the data to identify what genetic factors specific to Africans and African-Americans increase susceptibility to certain diseases. Knowing the genetic nature of the overwhelming variety among Africans can increase the efficacy of public health initiatives across Africa. It'll be fascinating to see where scientists go with this potent genetic data...
article link here
study link here
-Andrew Plan
Size Matters for Mosquitos and Malaria
By C. Paula de los Angeles
In reading about malaria, I came across an interesting blog that proposed controlling this infectious disease with genetically engineered mosquitos that had resistance to malaria. Essentially, these mosquitos would mate with wild ones and eventually spread resistance. In order for this to work, these genetically engineered mosquitos would have to be more attractive to the wild females than the wild males (sexual selection). But is it the mosquito of biggest size that always win? The answer appears to be no. In an experiment that varied mosquito size by controlling their diet, it was found that the middle-sized mosquitos were the most successful. This experiment was ideal because it was carried out in an isolated, malaria-filled part of Tanzania, meaning this public health policy could realistically be implemented. What a great way to use sexual selection to cure infectious disease!
BLOG: http://scienceblogs.com/notrocketscience/2008/05/size_matters_for_mosquitoes_but_mediumsized_males_do_better.php
Reference: NGHABI, K., HUHO, B., NKWENGULILA, G., KILLEEN, G., KNOLS, B., FERGUSON, H. (2008). Sexual selection in mosquito swarms: may the best man lose?. Animal Behaviour
In reading about malaria, I came across an interesting blog that proposed controlling this infectious disease with genetically engineered mosquitos that had resistance to malaria. Essentially, these mosquitos would mate with wild ones and eventually spread resistance. In order for this to work, these genetically engineered mosquitos would have to be more attractive to the wild females than the wild males (sexual selection). But is it the mosquito of biggest size that always win? The answer appears to be no. In an experiment that varied mosquito size by controlling their diet, it was found that the middle-sized mosquitos were the most successful. This experiment was ideal because it was carried out in an isolated, malaria-filled part of Tanzania, meaning this public health policy could realistically be implemented. What a great way to use sexual selection to cure infectious disease!
BLOG: http://scienceblogs.com/notrocketscience/2008/05/size_matters_for_mosquitoes_but_mediumsized_males_do_better.php
Reference: NGHABI, K., HUHO, B., NKWENGULILA, G., KILLEEN, G., KNOLS, B., FERGUSON, H. (2008). Sexual selection in mosquito swarms: may the best man lose?. Animal Behaviour
Gates' Foundation Funding Super Cool Things
The Bill and Melinda Gates' Foundation is funding three groups of British scientists who are working on some pretty amazing things. One group, out of University of Exeter, is developing a magnet that can test whether a person has malaria parasites in their bloodstream. Another group is building a library of all the various HIV mutations in humans, documenting the various ways the virus has evaded immune systems, with the hopes of being able to create a vaccine against a large number of the variants of the retrovirus. One other group, from the Liverpool School of Tropical Medicine, is attempting to understand and mimic the human body's ability to carry the bacteria that causes pneumonia without contracting infection- this seems to limit and improve the immunity to other illnesses the bacteria causes. The hope of this research is to create an inhaled vaccine against pneumonia. Each group was given an initial grant of $100,000, with the chance to apply for more grants as their research progresses. There were about fifteen other projects that the Foundation is funding, and they all seem pretty progressive! Though the failure rate for a lot of this research is high, it's exciting to see someone funding these projects that could generate great improvements in human health.
http://www.timesonline.co.uk/tol/news/uk/science/article6222056.ece
-Kaitlyn
http://www.timesonline.co.uk/tol/news/uk/science/article6222056.ece
-Kaitlyn
Saturday, May 2, 2009
Origin confusion?
Science Magazine and the New York Times both reported this week on a new Africa-wide survey of human genetics, the largest ever to be conducted in that continent, which claims to pinpoint more closely the geographic origin of modern humans.
Unfortunately, the two articles appear to report conflicting results.
The New York Times’s Nicholas Wade reports, “The origin of species is generally taken to be the place where its individuals show the greatest genetic diversity. For humans, when the new African data is combined with DNA information from the rest of the world, this spot lies on the coast of southwest Africa near the Kalahari desert.”
Science Magazine’s “news” section, in contrast, says the study concludes that “East Africa was the source of the great migration that populated the rest of the world.”
I wasn’t able to access the researchers’ data or original report (it may not be online yet), which probably clears up this apparent contradiction. I’m assuming that Science’s “great migration” and the Times’s “origin of species” are actually two different things.
Nontheless—confusing! Those are the kinds of quotes that news sources can run with, and which might spread misinformation. I’ll post an update/clarification whenever I can get access to the actual research (…or when something comes up on the New York Times’s “corrections” page?). Responses welcome if anyone can figure out where the confusion lies.
The study’s data provides a lot more interesting information besides that on the “origin" question. Africa, despite being the continent with the greatest genetic diversity, has been underrepresented in genetic surveys, especially because the most diverse groups (like bushmen and hunter-gatherers) are logistically difficult to reach.
This group of researchers spent over 10 years collecting samples from some of the most remote populations in Africa, eventually ending up with blood from 3194 Africans in 113 different populations. They then searched the samples for over 1000 genetic markers, and sorted the DNA into similar clusters.
They found (luckily for them!) that those DNA-based clusters mapped well onto cultural and language groups. For example, the click-language groups—such as the Khoisan of south Africa and the Sandawe and Hazda of Tanzania—share common ancestors.
Researchers also found, through comparison with African-American DNA samples, that most African-Americans have ancestors from all over Africa, making it difficult to pinpoint a person’s origins to a specific group (as some DNA testing claims it can do).
There is hope the data will be used eventually for medical research--for example, to better understand why people respond differently to diseases and drugs.
Anne
Unfortunately, the two articles appear to report conflicting results.
The New York Times’s Nicholas Wade reports, “The origin of species is generally taken to be the place where its individuals show the greatest genetic diversity. For humans, when the new African data is combined with DNA information from the rest of the world, this spot lies on the coast of southwest Africa near the Kalahari desert.”
Science Magazine’s “news” section, in contrast, says the study concludes that “East Africa was the source of the great migration that populated the rest of the world.”
I wasn’t able to access the researchers’ data or original report (it may not be online yet), which probably clears up this apparent contradiction. I’m assuming that Science’s “great migration” and the Times’s “origin of species” are actually two different things.
Nontheless—confusing! Those are the kinds of quotes that news sources can run with, and which might spread misinformation. I’ll post an update/clarification whenever I can get access to the actual research (…or when something comes up on the New York Times’s “corrections” page?). Responses welcome if anyone can figure out where the confusion lies.
The study’s data provides a lot more interesting information besides that on the “origin" question. Africa, despite being the continent with the greatest genetic diversity, has been underrepresented in genetic surveys, especially because the most diverse groups (like bushmen and hunter-gatherers) are logistically difficult to reach.
This group of researchers spent over 10 years collecting samples from some of the most remote populations in Africa, eventually ending up with blood from 3194 Africans in 113 different populations. They then searched the samples for over 1000 genetic markers, and sorted the DNA into similar clusters.
They found (luckily for them!) that those DNA-based clusters mapped well onto cultural and language groups. For example, the click-language groups—such as the Khoisan of south Africa and the Sandawe and Hazda of Tanzania—share common ancestors.
Researchers also found, through comparison with African-American DNA samples, that most African-Americans have ancestors from all over Africa, making it difficult to pinpoint a person’s origins to a specific group (as some DNA testing claims it can do).
There is hope the data will be used eventually for medical research--for example, to better understand why people respond differently to diseases and drugs.
Anne
Crazy sea-grapes complicate Cambrian explosion
A submarine expedition to the Bahamas has discovered a new species—the “Bahamian groma”—a single-celled organism about one inch in diameter.
The creatures are reminiscent of grapes, or balloons, or “doo-doo balls,” according to researcher Sonke Johnson of Duke University.
Although similar mega-amoebas have been discovered around the world—the first in 2000 in the Arabian Sea—these are different in one important way: they’ve made tracks across the ocean floor. Although the grapes appear to be moving too slowly to be captured with the submarine’s video capabilities, researchers are convinced the tracks they’ve made can’t be created simply by ocean currents. The organisms sometimes head out in multiple directions from one spot, and are able to go up and down the ridges and valleys of the ocean floor.
The idea that such simple organisms could have created the tracks throws a wrench in current ideas about the Cambrian explosion—the rapid expansion of multicellular, complex life that happened about 530 million years ago.
Before discovering the creatures, themselves, researchers found grape-tracks in the pre-Cambrian fossil record and assumed this meant that bilateral creatures—the types of things we normally consider capable of making tracks—were around in pre-Cambrian days.
If, instead, the Bahamian groma were responsible for the tracks, it means that the Cambrian explosion may have been even more explosive than we thought, taking animal life from amoeba to us in a shorter amount of time than previously believed.
As far as researchers know, the Bahamian groma is like a giant balloon. Filled with water and almost neutrally buoyant, it floats along the very surface of the ocean floor by “eating” the stuff in front of it and “pooping” it out behind. They’re fragile and impossible to study in captivity, however, so nobody really knows.
They clearly reproduce, “because there were sure a lot of them,” says Johnson. But that process, as well, remains a mystery.
I learned about the grapes (and stole pictures) from this blog article, which referred me to this press release as well as the original 2008 paper in Current Biology, “Giant Sea-Protist Produces Bilaterian-like Traces.”
Interestingly, wikipedia’s Cambrian explosion entry mentions that Charles Darwin saw the Cambrian explosion “as one of the main objections that could be made against his theory of evolution by natural selection,” presumably because rapid diversification during the Cambrian period contradicted his ideas about slow, successive change. He acknowledges this in "Origin," saying that “several of the main divisions of the animal kingdom suddenly appear in the lowest known fossiliferous rocks,” and that this problem “at present must remain inexplicable, and may be truly urged as a valid argument against the views here entertained.”
-Anne
The creatures are reminiscent of grapes, or balloons, or “doo-doo balls,” according to researcher Sonke Johnson of Duke University.
Although similar mega-amoebas have been discovered around the world—the first in 2000 in the Arabian Sea—these are different in one important way: they’ve made tracks across the ocean floor. Although the grapes appear to be moving too slowly to be captured with the submarine’s video capabilities, researchers are convinced the tracks they’ve made can’t be created simply by ocean currents. The organisms sometimes head out in multiple directions from one spot, and are able to go up and down the ridges and valleys of the ocean floor.
The idea that such simple organisms could have created the tracks throws a wrench in current ideas about the Cambrian explosion—the rapid expansion of multicellular, complex life that happened about 530 million years ago.
Before discovering the creatures, themselves, researchers found grape-tracks in the pre-Cambrian fossil record and assumed this meant that bilateral creatures—the types of things we normally consider capable of making tracks—were around in pre-Cambrian days.
If, instead, the Bahamian groma were responsible for the tracks, it means that the Cambrian explosion may have been even more explosive than we thought, taking animal life from amoeba to us in a shorter amount of time than previously believed.
As far as researchers know, the Bahamian groma is like a giant balloon. Filled with water and almost neutrally buoyant, it floats along the very surface of the ocean floor by “eating” the stuff in front of it and “pooping” it out behind. They’re fragile and impossible to study in captivity, however, so nobody really knows.
They clearly reproduce, “because there were sure a lot of them,” says Johnson. But that process, as well, remains a mystery.
I learned about the grapes (and stole pictures) from this blog article, which referred me to this press release as well as the original 2008 paper in Current Biology, “Giant Sea-Protist Produces Bilaterian-like Traces.”
Interestingly, wikipedia’s Cambrian explosion entry mentions that Charles Darwin saw the Cambrian explosion “as one of the main objections that could be made against his theory of evolution by natural selection,” presumably because rapid diversification during the Cambrian period contradicted his ideas about slow, successive change. He acknowledges this in "Origin," saying that “several of the main divisions of the animal kingdom suddenly appear in the lowest known fossiliferous rocks,” and that this problem “at present must remain inexplicable, and may be truly urged as a valid argument against the views here entertained.”
-Anne
The origin of Native Americans
An interesting article came out a few days ago that settled the long-standing debate on whether Native Americans descended from one ancestral population or multiple populations.
Full text can be found here: http://www.sciencedaily.com/releases/2009/04/090428223836.htm
The article details a DNA study that provides very strong evidence for the descending of Native American populations from a single ancestral population. Says Karl Britt Schroeder, a lecturer at UC-Davis and one of the authors of the study:
"Our work provides strong evidence that, in general, Native Americans are more closely related to each other than to any other existing Asian populations, except those that live at the very edge of the Bering Strait"
The results of the study expands upon previous findings of what is termed the "9-repeat allele," which is a genetic marker that occurs in all 41 Native American populations sampled and is absent in all of the Eurasian, African, and Oceanian groups sampled. While the discovery of this allele strongly suggested the 'single ancestral population' theory, there was still a possibility that this allele's prominence could be due to mutations occuring separately in Native American populations or crossing over.
The study found that, in examining the bordering base pairs of the "9-repeat allele," there was a distinct pattern of base pairs not found in individuals without the allele, a pattern that is too short to have been promoted by positive selection and too prevalent to suggest multiple mutations. This is the first study supporting the 'single ancestral population theory' with evidence from DNA carried by both sexes.
In light of the results, it seems that the ancestors of the Native American population were indeed most likely to have been a single population that migrated in one wave to the Americas. This would account for the substantial genetic homogeneity both observed and inferred in Native American populations present and past, bringing to mind the innumerable cases discussed throughout the centuries of Native American populations genetically unequipped to combat foreign illnesses like smallpox.
-Andrew Plan
Full text can be found here: http://www.sciencedaily.com/releases/2009/04/090428223836.htm
The article details a DNA study that provides very strong evidence for the descending of Native American populations from a single ancestral population. Says Karl Britt Schroeder, a lecturer at UC-Davis and one of the authors of the study:
"Our work provides strong evidence that, in general, Native Americans are more closely related to each other than to any other existing Asian populations, except those that live at the very edge of the Bering Strait"
The results of the study expands upon previous findings of what is termed the "9-repeat allele," which is a genetic marker that occurs in all 41 Native American populations sampled and is absent in all of the Eurasian, African, and Oceanian groups sampled. While the discovery of this allele strongly suggested the 'single ancestral population' theory, there was still a possibility that this allele's prominence could be due to mutations occuring separately in Native American populations or crossing over.
The study found that, in examining the bordering base pairs of the "9-repeat allele," there was a distinct pattern of base pairs not found in individuals without the allele, a pattern that is too short to have been promoted by positive selection and too prevalent to suggest multiple mutations. This is the first study supporting the 'single ancestral population theory' with evidence from DNA carried by both sexes.
In light of the results, it seems that the ancestors of the Native American population were indeed most likely to have been a single population that migrated in one wave to the Americas. This would account for the substantial genetic homogeneity both observed and inferred in Native American populations present and past, bringing to mind the innumerable cases discussed throughout the centuries of Native American populations genetically unequipped to combat foreign illnesses like smallpox.
-Andrew Plan
Friday, May 1, 2009
Origin of life may not have been from hot soup
Darwin wrote that some "warm little pond" that contained all the necessary ingredients of life such as ammonia, light, heat, electricity, etc. would beget the first living creatures. This is not far from our current understanding of the primordial soup based on experiments by Urey and Miller that life had a "hot start". However, this belief has been under fire for some time because hot temperatures cannot support a stable environment for structures appropriate for life to form. However, new theories have emerged that so-called "psychrophiles", or cold-loving microbes, might be the new instigators of life. If we can imagine thermophiles living in hot sulfur springs, it's not too much of a stretch to imagine bacteria living in polar ice sheets and temperate glaciers. The sun's luminosity was 30% lower than now, producing a subzero earth.
Research in the past 10 years shows that freezing can concentrate and stabilize molecules more and allow formation of more complex structures. Experiments have shown that simple molecules trapped in ice veins can produce simple nucleic acids in the course of 30 years. However, I'm curious to know whether 30 years is an appropriate time frame for structure formation comparable to that in a hot environment. 30 years seems quite a contrast to the hot trigger from Urey and Miller's applied electricity. If a cold start is still questioned, the cold could've still acted as a selection factor for the common ancestral organism that gave rise to all life forms. Could that be defined as the more significant origin of life then? Well, the cold hypothesis can be quite powerful if seen in light of current exploration of possibilities of life on other worlds, i.e. Mars and various moons of Saturn. These are all very cold places!
-Bonnie Chien
Research in the past 10 years shows that freezing can concentrate and stabilize molecules more and allow formation of more complex structures. Experiments have shown that simple molecules trapped in ice veins can produce simple nucleic acids in the course of 30 years. However, I'm curious to know whether 30 years is an appropriate time frame for structure formation comparable to that in a hot environment. 30 years seems quite a contrast to the hot trigger from Urey and Miller's applied electricity. If a cold start is still questioned, the cold could've still acted as a selection factor for the common ancestral organism that gave rise to all life forms. Could that be defined as the more significant origin of life then? Well, the cold hypothesis can be quite powerful if seen in light of current exploration of possibilities of life on other worlds, i.e. Mars and various moons of Saturn. These are all very cold places!
-Bonnie Chien
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