Evolution: 24 myths and misconceptions

[Moridin]

Evolution: 24 myths and misconceptions

The following myths are debunked:

- Everything is an adaptation produced by natural selection
- Natural selection is the only means of evolution
- Natural selection leads to ever-greater complexity
- Evolution produces creatures perfectly adapted to their environment
- Evolution always promotes the survival of species
- It doesn't matter if people do not understand evolution
- "Survival of the fittest" justifies "everyone for themselves"
- Evolution is limitlessly creative
- Evolution cannot explain traits such as homosexuality
- Creationism provides a coherent alternative to evolution
- Evolution must be wrong because the Bible is inerrant
- Accepting evolution undermines morality
- Evolutionary theory leads to racism and genocide
- Religion and evolution are incompatible
- Half a wing is no use to anyone
- Evolutionary science is not predictive
- Evolution cannot be disproved so is not science
- Evolution is just so unlikely to produce complex life forms
- Evolution is an entirely random process
- Mutations can only destroy information, not create it
- Darwin is the ultimate authority on evolution
- The bacterial flagellum is irreducibly complex
- Evolution violates the second law of thermodynamics

 

[Cincinnatus]

That article points out that evolutionary psychologists are notorious for that first fallacy "everything is an adaptation produced by natural selection". I'd like to second this one, they really do use this, practically as the starting point to their entire theory.

Richard Lewontin (famous evolutionary biologist) wrote a fantastic article explaining why the evolutionary psychology position is flawed. Here's a link:

http://www.isrl.uiuc.edu/~amag/langev/paper/lewontin98theEvolution.html

For the counter-argument, read anything by Tooby and Cosmides (coauthors).

 

[Moridin]

Actually, that misconception was not that adaptionism or evolutionary psychology are flawed as such, but that it is false to think that all behavior is genetically determined, such as liking TV dinners. Also, we know quite a lot about the evolution of human cognition.

 

[Cincinnatus]

Actually, that misconception was not that adaptionism or evolutionary psychology are flawed as such, but that it is false to think that all behavior is genetically determined, such as liking TV dinners. Also, we know quite a lot about the evolution of human cognition.

My point wasn't that we don't know anything about the evolution of human cognition. Nor was it even that evolutionary psychology hasn't said anything true about it. It was that evolutionary psychology is flawed *as a methodology*.

Evolutionary psychology isn't really a theory about the evolution of cognition. It's more about trying to explain particular behaviors that exist today by saying that they were once adaptive. So it's a theory about why modern humans do the things they do, adaptationist reasoning is just their (flawed) methodology.

Speaking of what we do know about the evolution of human cognition. The FOXP2 story is a particularly interesting example of how we can start to answer these kinds of questions (without resorting to adaptationist reasoning). A family was found with a heritable speech and language disorder. The disorder was linked to a particular mutation in the gene FOXP2.

Further studies were performed that showed FOXP2 and its homologs in other animals to be involved in the development of the brain (and other structures). Interestingly, a particular mutation in FOXP2 that may significantly affect how it regulates other genes involved in brain development was found to have occurred sometime after we split off from our closest common ancestor with modern apes.

Even more interestingly, by analyzing the normal within-species variability of FOXP2 homologs and comparing it to the variability found in human FOXP2, it was found that FOXP2 has been undergoing much more significant natural selection relatively recently in human history than it ever was in other species. This is precisely what we would expect to find in a "language-gene" since language itself is uniquely human and thought to be a relatively recent development.

In my opinion, results like these tell us much more about the evolution of cognition than adaptationist speculation.

 

[_Mayday_]

Okay, I am a biologist, even if it is at school. I have waited a while to learn the basics, but now I would like to buy a book that goes over evolution, I think it is one of those things that everybody thinks they know but probably don't. Cheers, and interesting list! How would have a wing be useful? Or is it that half a wing could have been better than no wing?

 

[Cincinnatus]

Okay, I am a biologist, even if it is at school. I have waited a while to learn the basics, but now I would like to buy a book that goes over evolution, I think it is one of those things that everybody thinks they know but probably don't. Cheers, and interesting list! How would have a wing be useful? Or is it that half a wing could have been better than no wing?

There are so many good books about evolution out there! I recommend just going to a local bookstore, looking through the biology section and picking whichever one sounds most interesting to you. If you need suggestions.. Off the top of my head I would recommend anything by Steven J. Gould, Richard Lewontin or Richard Dawkins as probably being particularly well written.

If you do read these guys, keep in mind that they don't always agree with each other! Of course, if you're like me then you'll find their disagreements to be the most interesting part. Try looking up their reviews of each other's books for fun.

 

[Moridin]

Evolutionary psychology is not controversial when applied to other animals and has yielded quite a lot of understanding. The only critics seems to be people, like Gould, who was heavily influenced by Marxist thinking, although that is not a general observation, since the same applies to Maynard Smith, who was at the polar opposite of the debate.

Cincinnatus, what you described was, in fact, a form of adaptionist reasoning.

 

[_Mayday_]

- Half a wing is no use to anyone

Can someone please expand on this idea? How is a half a wing benificial to an animal in terms of survival?

I have Dawkins book 'The Selfish Gene' and I am really not enjoying it at all. I just want a book that talks you through evolution.

 

[Moridin]

Can someone please expand on this idea? How is a half a wing benificial to an animal in terms of survival?

I have Dawkins book 'The Selfish Gene' and I am really not enjoying it at all. I just want a book that talks you through evolution.

The key here is exaptation (cooption). A trait can evolve because it served one particular function, but subsequently it may come to serve another.

What Good is a Half Wing?
Evolution myths: Half a wing is no use

If you think The Selfish Gene is too complicated or boring, you should try some other book. Speaking of wings, Climbing Mount Improbable is a shorter book by Dawkins where he spends an entire chapter talking about wings (pp. 38-73).

Another accessible book on evolution is "Evolution: The Triumph of an Idea" by Carl Zimmer.

 

[ojos_de_cielo]

Can someone please expand on this idea? How is a half a wing benificial to an animal in terms of survival?

I have Dawkins book 'The Selfish Gene' and I am really not enjoying it at all. I just want a book that talks you through evolution.

Actually, half a wing is better than no wing at all because it helps you stay up even if it's for a little bit of time, that little bit of time may be the difference between not reproducing and reproducing. I read this in either "River out of Eden" or "The God Delusion", both by Dawkins.

 

[_Mayday_]

Thanks!

 

[Moonbear]

Can someone please expand on this idea? How is a half a wing benificial to an animal in terms of survival?

I have Dawkins book 'The Selfish Gene' and I am really not enjoying it at all. I just want a book that talks you through evolution.

Sometimes it's annoying when the explanations are as bad as the questions. Why would half a wing NEED to be BENEFICIAL to survival? That's one of those common misconceptions about natural selection as it pertains to evolution. The only thing half a wing NEEDS to be is NOT DETRIMENTAL to survival to reproductive maturity. As long as an animal isn't greatly hindered by the "half wing," there's no reason for these genes not to be passed on.

But, let's take this question a step further. What exactly is "half a wing" anyway? A wing is a limb, modified in a way that permits flight, just as a flipper is a limb modified in a way that aids in swimming, or a leg is a limb modified in a way that aids in walking. So, is half a wing anything that doesn't function in flight but otherwise resembles the structure of a wing? Or is it a structure that resembles instead a flipper or leg but shares some traits of a wing (I don't know...a leg with feathers or webbing between one's fingers or toes?) Here are some examples that come to mind. A bat has wings, but structurally, they are quite different from a bird's wings. Basically, a bat wing is that webbing between the fingers example. Embryologically, humans have webbing between the fingers too. It doesn't require much to have the apoptotic process disrupted and that webbing retained rather than lost before birth. So, that bat wing is quite functional as a wing, yet it's hardly any different from a leg (and if you've ever watched a bat creep around on the floor rather than in flight, you'll notice they do manage to use their wings to assist in walking too, albeit rather awkwardly). Is that half a wing? Where else do we see functional webbing between toes...duck feet come to mind. It's not a forelimb, but a hindlimb, and they don't aid in flight, but they work great as paddles in the water. Structurally quite similar to a bat's wing. Is a webbed duck foot half a wing. It doesn't hinder them walking around with webbing on their feet.

What about penguins that have wings but can't fly? Their wings are actually much better suited as flippers that aid them in their swimming. Is that half a wing? Or is that half a flipper?

In each of the above cases, these are examples where there is functionality of these modifications that do aid in survival.

But, what about the ostrich? They have wings that don't help them fly. They don't help them swim either. They get around just fine on two legs. So, what do those wings do? Perhaps aid in maintaining balance, although usually they keep their wings tucked down while walking. Is that half a wing? It's an example of a species that gets little benefit from having those wings, other than perhaps for the sake of displays for courtship or warnings against intruders, yet survives just fine in spite of it.

 

[Holocene]

Can someone please expand on this idea? How is a half a wing benificial to an animal in terms of survival?

I have Dawkins book 'The Selfish Gene' and I am really not enjoying it at all. I just want a book that talks you through evolution.

Try "The Blind Watchmaker", also by Dawkins.

As far as half a wing...

Ever see a captive bird with its wing clipped? They cannot sustain flight, but flight is in their nature, and they will keep trying to fly. Some can even get pretty far before finally making a genetle, (but forced) landing. That right there is comparable to having half a wing. Just because the animal cannot fly with it, doesn't mean it doesn't offer major advantages cpmpared to animals with no wings at all. A bird with clipped wings can survive a fall from a tree.

 

[mgb_phys]

As far as half a wing...

An even better way to think of it, is that birds currently only have half a wing - when compared to the wings they will evolve in the future!
There is a common (often unconcious) mindset that evolution was in the past and animals today are evolved and therefore finished.