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Behavior May Influence Evolution
eldavojohn writes "Pending your beliefs about evolution, National Geographic is running an interesting article on the influences of behavior on evolution. The study supports the controversial idea that an animal's behavior in response to environmental change can spur evolutionary adaptations. By adding a predator to an island where a species of lizards lived with no predators, they witnessed a quick shift in the average length of legs on the lizards. Long legs meant to escape were useless against the new larger predators while short legs became the dominant feature since they increased climbing ability (to trees the predators could not reach). For the finer details on the research, visit the Losos Lab Research Page."
This isn't evolutionary adaptation - it's much more simple than that. If you start killing all of the lizards with long legs, the ones with short legs are going to mate and have offspring with short legs. There is nothing new or "adapted." Also, if the short-legged ones get away and the long-legged ones don't, isn't that going to inherently affect how many have long legs and how many have short, by proportion?
From the article description, I thought this experiment was going to provide evidence for Lamarkism or something. In fact, this seems an interesting, but not too-surprising finding.
Introduce a change to the environment that causes a behavioural change - is it so surprising that some members of the population are better suited to the behaviour than others?
Apropos nothing, it's pretty sad to see such a story headed with the words "Pending your beliefs about evolution" on a site such as Slashdot. Evolution is an observable fact. Evolution through natural selection is a massively successful and well supported theory.
I'm not sure I agree with you about the possibility of any controvesy here. I, obviously, haven't read the article so I'm just responding to your comments here.
Firstly Evolution is not always controversial, a massively insignificant minority occasionally try to cast aspersions upon it but this doesn't make it controversial.
Secondly I don't see the choices made by the lizards to live in trees rather than remain on the ground and be eaten by predators is any different to the way I understood evolution to work in general. The way I see it in this case living in the trees is more likely to make you live long enough to breed than continuing to live on the ground, animals with shorter legs are better at climbing trees and more likely to be able to get up them in time rather than their long legged cousins who get eaten. Does the article suggest that those animals with long legs don't take to the trees for their survival or that they do but are just not good enough at tree climbing to escape successfully ?
Basically it looks to me like the physical attributes of the animal are determining who is evoloutionarily successful and its simply the pressure of the enviroment which is creating a shorter legged species which prefers to run up trees.