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Gene ExpressionBy Razib KhanOctober 5, 2007 5:33 AM


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Evolution happens faster than originally assumed:

Studying animals from Bighorn sheep to guppies, the research has revealed that animals are evolving to human changes in the environment within 200 generations. "They can be pretty dramatic [changes]," Kinnison said. ... "People are just catching on to how important these changes are," Kinnison said. The changes discovered in these species showed that those driven by human intervention appear nearly twice as fast as those driven by a natural environment, according to a press release.

The above was a press release from the University of Maine and so one assumes that the researcher doesn't have such naive beliefs about the "rate of evolution," as if it is subject to narrow constraints as opposed to being contingent upon the parameters (e.g., mutation rate, population size, strength of selection, correlation between genotype and phenotype, etc.). Why should it surprise that animals exposed toward the selective pressure of humans are subject to extremely rapid evolution? Our cultural caprice moves at a quicksilver pace. We also change the parameters of the game so as to facilitate evolution (e.g., increase population size and rev up selection coefficients, engage in selective inbreeding, and so on). As it happens the researcher above has a paper out in Molecular Ecology, Eco-evolutionary vs. habitat contributions to invasion in salmon: experimental evaluation in the wild:

Although trait evolution over contemporary timescales is well documented, its influence on ecological dynamics in the wild has received much less attention particularly compared to traditional ecological and environmental factors. For example, evolution over ecologically relevant timescales is expected in populations that colonize new habitats, where it should theoretically enhance fitness, associated vital rates of survival and reproduction, and population growth potential. Nonetheless, success of exotic species is much more commonly attributed to ecological aspects of habitat quality and 'escape from enemies' in the invaded range...The scope of this fitness evolution far exceeds the scale of divergence in trait values for these populations, or even the expected fitness effects of particular traits. These results suggest that contemporary evolution can be an important part of the eco-evolutionary dynamics of invasions and highlight the need for studies of the emergent fitness and ecological consequences of such evolution, rather than just changes in trait values.

Here's a digest summary. Humanity is going to have a major phylogenetic impact on the history of life on earth even if we quickly go extinct. Consider that we have introduced red deer to New Zealand, camels to Australia, reintroduced wild horses to North America and made nutria a feature of American southeast. These are just the larger and more charismatic fauna. Don't even get me started on zebra mussles or thousands of "weeds."

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