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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.
No doubt "behaviour influencing eveloution" will be seized upon by the intelligent design brigade. Though as usual the headline is misleading. Instead of evolution on one axis (e.g. speed) it's on a combination of various abilities (running fast/hiding/climbing/fighting) plus choosing the right strategy. If the rules of the game change, e.g. a faster predator comes along, what you see is what you'd expect - those adapted for running away (as opposed to the hiders, the climbers, the smelly chemical squirters) are now at a disadvantage; they're fighting the previous war. Nothing to see here.
It's true I tell you, feller at work's next door neighbour read it in the paper.
That's not what they're suggesting. There are multiple layers of incorectness here, but the study itself seems interesting.
The original poster is merely regurgitating the sentiment of the article, but they're both wrong about the "controversial" idea supported by the study.
All that the study suggests is that evolutionary changes can happen quickly when new selection pressures are applied, or, more importantly, when a group of thikning creatures takes a different approach to a problem (which may be a genetically pre-disposed choice).
The National Geographic article, and particularly the poster here, seem to think that the Anoles wanted smaller legs and received them, for their young. This is more like the pre-Darwinian view of multi-generation adaptation, and the study makes no such claims.
Keep in mind that a shift in leg-length in the span of six months, while significant, isn't as amazing as it may sound. Brown anoles lay an egg every week, and that egg hatches in under a month. Anyone who's been in a tropical region in which anoles are indigenous can likely attest to their ability to rapidly reproduce.
I've recently been "Studying" evolution in my spare time.
This is a cool experiment, but it's nothing "new" -- there's no new knowledge here. At all.
AND there's NOTHING AT ALL about "behavior may be inherited!" Where did THAT come from -- anyone?(*) All these lizards were already prone to running up trees. The ones with shorter legs did it better, and within just a few generations the average legs length of the population was shorter.
That's *basic* evolution, people. Go read a damn book!!! The submitter of this article makes me angry because I realize now the fight for education about Evolution isn't just for stupid fundamentalists. A lot of smart people don't get it either.
I highly recommend getting yourself a copy of "The Selfish Gene" by Richard Dawkins. Read all the chapter notes, too -- get the recent version, don't gt an original copy because it makes you cool. Dawkins commentary on what he wrote in the newer printings is invaluable. It's an excellent book, and it's FUN to read... seriously!
(* I mean, in this context. It's well-known that behavior is inherited -- but not learned behavior.)
I read awhile back about comparing possum on an isolated island showed a much stronger genetic base that produced better litters and eventual adults versus those who lived on the mainland.
Apparently the stress put on possums on the mainland is high enough to cause genetic changes. the stress weakens the immune system and has other side effects that produced a less healthy and capable possum. One possibility that was raised is that on the mainland a good number of possum are killed by vehicles. Cars are obviously a predator that mainland possum can adapt to, or maybe there hasn't been enough time yet?
I wish I could find the exact story but all I end up with are references to NZ based studies.
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* Winners compare their achievements to their goals, losers compare theirs to that of others.
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.
I still don't see how this departs from the basic ideas of evolution.
A new predator was introduced, altering the environment in which the lizard operates. Suddenly running away is less effective than climbing trees, so lizards with the tools and inclination to climb trees survive at a better rate in the new environment. Perhaps a naive observer might read some "decision" on the part of the lizards into this, but it looks like pretty simple natural selection to me. The instincts and behavioural patterns of animals are as much subject to natural selection as their physical makeups (particularly at the level of these little fellows, learning by imitation has been shown to be something even apes struggle almost impossibly with, so their instincts are all the lizards really have to guide them), so I'm still at a loss as to how the fact that in a highly pressured evolutionary situation both evolve in tandem is somehow novel or suprising.
MP
"Firstly Evolution is not always controversial, a massively insignificant minority occasionally try to cast aspersions upon it but this doesn't make it controversial."
He's not talking about Christian fundamentalists, he's talking about scientists, biologists, geneticists, etc. If you think that they are in lock-step agreement about evolution, and they never disagree or argue or have controversies, you've never been to an academic conference. Case in point: punctuated equilibrium.
Computers are useless. They can only give you answers.
-- Pablo Picasso
Evolution can be divided into two parts, adaption and speciation. Adaption is merely the process of physical changes to adjust to the environment. It isn't a theory as it has been observed many times (note the original article), and it should only be controversial to people who believe OJ is innocent. Speciation is when a new species arises from a different one. This is a theory, and I suppose it is highly controversial to some (many). *shrugs* But, the mere concept of adaption can't possibly be controversial.
As to the main point of the article, I don't quite get it. Behavior didn't cause the evolution, suitability to a behavior caused evolution. That doesn't seem so difficult to grasp to me. The ability to do this wasn't so important before, but then a pressure was introduced, and this ability turned out to aid in survival. Seems like a pretty straightforward application of the concept.
The behaviour of disbelieving scientific facts is the RESULT of a reduction in brain size due to a lack of intelligent stimulation.
I don't read your sig. Why are you reading mine?
Parent won't get modded up because, as stated in below threads, if you question evolution you're lacking in brains.
Maybe it's just me, but that idea sounds kind of stupid.
Firstly Evolution is not always controversial, a massively insignificant minority occasionally try to cast aspersions upon it but this doesn't make it controversial.
Science which is not controversial might as well be religion.
It's not a knock for or against evolution, just a thought that people too quickly label "evolution" that which is simply stronger traits surviving under different conditions.
Huh? You're making a distinction that doesn't exist. Evolution is the change of the frequencies of alleles within a population over time do to differential reproductive success of individuals. There are a lot of reasons for this differential reproductive success, but two biggies are being alive to reproduce (you didn't get eaten or starve to death) and that you are acceptable to a member of the opposite sex (If you're big and tough and can find lots of food, it doesn't matter, because if the girls don't like the way you look, you don't pass on your genes).
Basically this is what you are defining as adaptation, and then call it different than evolution, which you don't define. Usually the people that I see making this distinction are opponents of evolution that do so because they can't deny adaptation or "micro evolution" (to many examples available in real life), but still want to be able to argue against evolution on a larger scale.
Anyways, the point is, adaptation is evolution by the definition that biologists use. Defining it otherwise is what people do in order to protect their religious and philosophical beliefs.
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).
This could simply be the animals with long legs being eaten at a more frequent rate, so the short legged lizards are the ones surviving and reproducing. This is, at best, micro-evolution. Their genetic makeup isn't changing to accomidate the need for short legs (like evolution would *know* that it needed short legs). Its selective breeding.
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