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.”


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.


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