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

Why is this controversial?

[the_skywise]

It only makes sense. If the "animal" is intelligent to overcome its primal instincts it can avoid "evolutionary" dangers.

Are we not doing seeing this now in humans with antibiotics? Genetic manipulation?

How many people on Slashdot have said that the gene pool has become watered down due to the protections of civilization?

Re:Why is this controversial?

[Daniel_Staal]

I've read good arguments that many of these are actually adaptations that will help the species survive.

Think about it: who is more likely to say 'fuck civilization': A person with perfect eyesight, or someone who needs that civilization to buy their next pair of contact lenses?

Re:Why is this controversial?

[ThosLives]

Actually, I just realized that an animal cannot evolve; only populations can evolve. For instance, there were always some combination of small-legged and large-legged lizards in the cited example. However, what has changed was the distribution of those sub-characteristics within the overall population.

What really gets me is what 'behaviour' has to do with anything when there is simply an environmental change.

Note that I think this is distinct from evolution by mutation, which is the actual addition of characteristics; subtraction of characteristics I don't think is really 'evolution' in the sense that most people think (for instance, if all of a certain trait has been killed off, if the influence that killed it off is removed, it's not going to simply come back without another mutation somewhere (discounting things like recessive traits, of course).

Re:Why is this controversial?

[radtea]

How many people on Slashdot have said that the gene pool has become watered down due to the protections of civilization?

In the past 200 years (10 generations by conventional reckoning) the human population of Earth has increased more than six-fold.

This huge increase in population has been accompanied by virtually no selective pressure. We know that because "selective pressure" is a nice polite way of saying, "loads of people dying." Evolution operates via differential survival of different bloodlines, and you can't get rapid population expansion if pretty much everyone isn't living to breed.

Ergo, we are all members of the least "fit" (by any pre-industrial evolutionary standard of "fit") population of humans who have ever inhabited this planet.

And if you believe any of that matters, you might want to contemplate the fact that the over the same period of time the population of the United States has increased ten-fold rather than six-fold, faster than virtually any other nation, and most of it has been due to fertility, not immigration. China, in contrast, has had only about a factor of four growth in the same interval.

However, anyone who believes that this rapid population growth means the gene pool is being "watered down" is missing a fundamental aspect of evolution, which is that diversity is the basic currency of genetics. Far from being "watered down" by this expansion, the human gene pool has been enormously enriched by diversification, particularly by our penchant for exogamy: breeding far outside our local genetic group. In constrast, the least "watered down" gene pools on the planet can be found amongst the inbred populations of isolated communities and tribes. These places show great genetic homogeneity, and are therefore far more subject to problems of disease than more diverse populations.

Only people who believe the falsehood that certain evolutionary outcomes are "better" than others by something other than their own parochial standards of morality are going to be concerned about the vast increase in human diversity that has occured in the past 200 years. From an evolutionary standpoint this increase in diversity is only a good thing, and if you are concerned about it, is because either you don't understand this, or you are imposing your own moral standards on the outcome. There is nothing wrong with imposing your own moral standards on the outcome, but do not do so in the name of evolution.

There are ecological concerns regarding human population growth, but from an evolutionist's point of view it is a very good thing.

Re:Why is this controversial?

[marcello_dl]

Right wingers can't be religious people. They can only assert they are (and they probably know it since they kill religion the same way fascism kills nationalism) but reading the ABC of most religions proves the opposite.

This discovery seems to me more "dangerous" for current science theories than current religions. It implies that will could have a different meaning than the mere transition of electrons in some areas of the brain. Down with Darwin, go Lamarck :D

It disproves the higher power Direct intervention in reality, sure. But didn't the predominance of an OS like windows have the same effect, or stronger? Anyway I didn't believe in it already, even if I believe in the possibility of a higher power being responsible for reality. If you think about it, imperfect creatures created by the higher power are much more problematic for theology than a higher power creating the universe, giving freedom to everything inside.

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.

Re:Why I Used the Word 'Controversial'

[Angostura]

First off, anything about evolution is controversial.

No. Really, it's not. It;s directly observable - you can see this from the experiment.

Second, it's controversial because if these animals didn't become tree-born, this quick evolution of short legs never would have happened.

.

Nothing controversial about that. If peahens didn't prefer to mate with showy males as a measure of fitness, presumably we wouldn't have peacocks.

 

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.

No. This almost suggests nothing of the kind. The lizards tried to escape by climbing. Those with shorter legs were better climbers and were therefore "fitter" the lizards didn't sit around stroking their chins and devising a cunning new survival strategy.

Maybe you can argue that it was only natural for them to seek safety in the trees

.

Precisely. This was clearly a behaviour used by the ancestral lizards when there were predators.

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.

Uh - yeh, OK. So what's the problem? No controversy there.

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

What? That's just silly. Short legged lizards are better at climbing trees and survived It's as simple as that. Long legged ones could neither climb very well, nor run fast enough to escape. They were shit out of luck.

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.

It's been a long time since I read it, but he makes a persuasive case that farming took off in certain regions because the natural wildlife were well adapted to being used as crops (large grain size etc.)

Can we call this evolution?

Nope. You can call it the predominance of a successful meme, if you want.

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.

You're seeing controversy where none exists. Really. Behaviour effects evolution and vice versa all the time and it has nothing to do with conscious decision. A classic case. In the UK hedgehog behaviour has changed dramatically over the last 40 years. They no longer curl up in a spikey ball when threatened by cars on roads - they run for it?

Why? Because the ones that curled up didn't have many offspring.

Re:Adaptations?

[$RANDOMLUSER]

No, it's saying the bahavior of climbing tress rather than running away led to differential selection for the tree climbers. Sort of like the way men who fell asleep after sex left more offspring than the ones who got up and left.

They're not evolving. They're like ants.

[Esteanil]

To clarify:

A good example of phentotypic plasticity is found in ants. The different castes of ants in a hill are very different, such as workers and guards. This difference isn't found in their genes. Their genomes contain the molds for all the variations.
The eggs are treated differently, and this results in vastly different creatures coming out of the egg.

This is what the study suggests is happening, to a lesser degree, in the lizards.

The National Geographic article is wildly inaccurate.

That's what the *article* is saying. Not the study

[Esteanil]

The author of the article has wildly misunderstood the study.
What the study is saying is: "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 something we find amongst other thing in ants.
The various castes of ants (workers, warriors, etc) differ from eachother quite a bit. However, their genes are the same - Their genome holds the molds for all their various forms. Through different treatment of the eggs by the queen and the workers, different parts of the genome is activated.

So the study is suggesting that these lizards have evolved this ability: To, through some mechanism still unknown, influence the leg length of their children to pick between at least two different phenotypes. One with short legs, one with longer ones.
Interesting? Sure. Changing "Evolution's Driving Force"? Definitively not.
Someone needs to introduce the author of the article to an anthill. It would blow him away.

It's not controversial - the Baldwin Effect

[Anonymous Coward]

It's not particularly controversial

It's called the Baldwin Effect - http://en.wikipedia.org/wiki/Baldwin_effect

It's also been demonstrated in computer generated artificial life environments.

It's not that the animals wants to evolve in a particular direction.

It's simply that behavior affects the environment, and environment affects evolution.

There are some reasonably good examples on the Wikipedia page

Quatermass

Re:Article is wrong - Study misinterpreted.

[mrogers]

If phenotypic plasticity could affect the development of sperm cells, would it provide a plausible mechanism for Lamarckian evolution? For example, could environmental factors affect the concentration of proteins that might influence the crossover process during meiosis? Might this explain why sperm are produced continuously rather than being produced before birth and stored, like eggs?

Re:Article is wrong - Study misinterpreted.

[Esteanil]

Interesting thought, but no.
Phenotypic plasticity can only select between states already present in the genome. Activating a certain subset of genes, but not altering the genome as is required in Lamarckian evolution.
(Lamarckian evolution in a nutshell is generations of giraffes stretching their necks to reach the higher leaves, passing the added length they train through life on to their decendants)

What could (as far as I understand) be theoretically possible, is for males to "select" the sperm to produce from a set of phenotypes. Perhaps dependent on hormonal activity, etc. (Producing "warrior children" if they had been stressed, angry and afraid over a long period of time?)
Don't really know if it's possible, but it would give a distinct survivability advantage to be able to "devolve" the next generation back to an earlier phenotype if conditions were too harsh...

/. kisses up to pseudointellectuals article flameb

[bubbaD]

You may be overly trusting in the article writer. The writer may have deliberately misinterpreted the article so as to create a controversy, base on the study's title. The idea that behavior doesn't influence evolution would actually be a whole lot more controversial among people who understand the subject. You could post exactly the same information, put a headline to the effect that it supports 'intelligent design theory,' and watch the outraged comments pile up! What fun!

Re:Mod Parent UP

[Anonymous Coward]

And you misunderstand me. I don't really care if you believe in evolution or not. The attitude of "your brain is smaller and your less intelligent because you don't believe in evolution" is total crap.

The pompous attitude of some of you people tick me off.

/rant

Re:Article is wrong - Study misinterpreted.

[callistra.moonshadow]

I've mentioned this before in a similar article months ago. There are studies of twins separated at birth, either raised at sea level or high in the Andes. Even though the two individuals are genetically identical the ones raised in the mountains are barrel chested and stout whereas the siblings raised at sea-level are average. Plasticity due to behavior (needing to breath deeply in a thin atmosphere - perhaps not voluntary but still a behavior), caused a person to develop differently.
Link to one article:
http://jeb.biologists.org/cgi/reprint/204/18/3151. pdf
It often makes me wonder if we will begin seeing people naturally born more darkly pigmented given the current state of the ozone.
Just some food for thought.


Cally