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."

Comments

Will we adapt?

[MECC]

The study also supports a somewhat controversial idea in biology: Animals' behavior in response to environmental change can spur evolutionary adaptations.

Could that imply that the behaviour of disbelieving scientific facts could spur a reduction in brain size in order to adapt to reduced intelligence?

And in other news...

[Daniel_Staal]

When the environment changes, some animals are better adapted to the new change than others. Details at 11.

Why I Used the Word 'Controversial'

[eldavojohn]

Why is this controversial?

Well, as I am the poster of this story and enjoy many things about evolution (book recommendation), I'll give you the best answer I can though I am not an evolutionary biologist. First off, anything about evolution is controversial. Second, it's controversial because if these animals didn't become tree-born, this quick evolution of short legs never would have happened. A lot of evolutionary theory revolves around evolution not by choice (example of the brown moths becoming dominant over white moths during the industrial revolution when smoke and carbon on trees and buildings hid them). But this almost suggests that the decision to take to the trees is in and of itself a factor in evolution. So it appears that there is evolution by way of behavior in addition to random mutations. I guess what I'm saying is that a lot of people consider evolution to be purely random ... but this study suggests that behavioral choices influence that.

Maybe you can argue that it was only natural for them to seek safety in the trees but I think that this study addresses something we must face. If you believe in evolution, you have to acknowledge that it's not only random genetics but also influenced by the behaviors of the animals granted those random mutations. If the lizards had behaved differently and not gone to the trees, perhaps longer and longer legs would have been developed until they were fast enough to outrun their predators. Or perhaps the species just would have been eradicated on the island.

Controversial because it implies that species may be able to subconsciously choose which feature is 'evolved' to be the dominant factor.

If you want to apply this to human evolution (as one is naturally only concerned with their own species), then I suggest you read Guns, Germs & Steel by Jared Diamond. What I found interesting is that in some places, humans began a farming lifestyle earlier than other hunter-gatherers. It was this decision by way of discovery that led some civilizations to outpace others. In fact, the choice or 'discovery' of planting seeds and harvesting them periodically eventually led to some regions invading and 'colonizing' other regions. Can we call this evolution? Can we say that some evolution hinges on behavioral choices? I think we can, but that's why it's controversial because it has traditionally been thought that the dominant feature was only influenced by the environment--not by a choice made by the animal.

Article is wrong - Study misinterpreted.

[Esteanil]

I'm hijacking a higher thread since pretty much everything written below is just plain wrong.
Not the submitters' fault, they simply read the article and based what they wrote on it.

Let me explain:
The article is claiming that "Evolution's Driving Force Shifts Based on Behavior"
Go to the actual research site (linked in submission), scroll down to the end, and you will find that what they're saying is:
"... another alternative is that lizards growing in different environments grow different length legs. To test this hypothesis, we raised baby anoles on two different surfaces at the St. Louis Zoo--either on 2x4's or on narrow (1/4") dowels. At the end of three months, the lizards raised on broader surfaces had longer limbs than the lizards on narrower surfaces! This suggests that the results observed in the field may be the result of a phenotypic plasticity in limb growth, rather than genetic differentiation."

Phenotypic plasticity is a term some of you may be unfamiliar with, a good example of it is found in ants.

In any given hill, there are different castes of ants. Warriors, workers, etc. They are all quite different.
However, the differences are not genetic; they arise during development and depend on the manner of treatment of the eggs by the queen and the workers, who manipulate such factors as embryonic diet and incubation temperature. The genome of each individual contains all the instructions needed to develop into any one of several 'morphs', but only the genes that form part of one developmental program are activated.

This is what the study suggests is happening to these lizards.
They're saying there are at least two different 'morphs', one with long legs and one with short ones, in the genome of the lizards.
These are then selected between (through some so far unknown mechanism) based on the environment of the lizards.

"These findings suggest the intriguing possibility that phenotypic plasticity may play an important role in adaptive differentiation by permitting lizards to occupy different habitats; once subsequent mutations arise, these differences can then be elaborated upon by natural selection."

Now, let the ghosts of Lamarckism the article has raised from their graves go to rest.