Friday, November 13, 2009

The Theory of Evolution

 
Here's one of the submissions to Discovery Magazine's "Evolution in Two Minutes" contest. It's the one chosen by viewers [The Winner: Evolution in Two Minutes].

I wish we could stop talking about "The" theory of evolution. There's really no such thing and the term conjurs up thoughts of evolution being only a theory. A better term is evolutionary theory.1 A short description of modern evolutionary theory would include population genetics, the major mechanisms of evolution (natural selection and random genetic drift), and the latest theories of speciation. More sophisticated versions of evolutionary theory might include punctuated equilibria, lateral gene transfer, symbiosis, neutral theory, group selection, kin selection, species sorting and molecular phylogeny.

But before you can talk about any of these things you have to define evolution so that we all know what we're talking about. The consensus scientific definition of evolution—the fact, not the theory—is: "Evolution is a process that results in heritable changes in a population spread over many generations" or some related variation of that statement [What Is Evolution?].

The makers of these videos are free to select a definition that is not the consensus scientific definition but why would they do that? Is it a good idea to use another definition to teach the general public about evolution? What purpose does that serve?




It's OK to talk about The theory of natural selection or The theory of punctuated equilbria.

7 comments :

  1. What's with the "-wtf?!" at 00:20? It certainly turned me off.

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  2. The consensus scientific definition of evolution—the fact, not the theory—is: "Evolution is a process that results in heritable changes in a population spread over many generations" or some related variation of that statement
    Is this the consensus scientific definition? Does genetic change in populatons really fully describe evolution?
    I've seen worse: - change in allele frequencies - but those definitions are taking all interest out of evolution. Descent with modification is actually better: at least it focusses on phenotypes.

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  3. The definition refers to heritable changes, not genetic changes. Also the process that leads to it.

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  4. Heleen asks,

    Does genetic change in populations really fully describe evolution?

    No, it doesn't describe everything that happens in evolution.

    It's a minimum definition of evolution. It defines the smallest thing that has to happen before you can call it evolution.

    Descent with modification is actually better: at least it focusses on phenotypes.

    Why is this better? You can have evolution without changing phenotypes. Or do you deny that molecular evolution counts as evolution?

    The other problem with "descent with modification" is that it includes changes that we don't refer to as evolution.

    Why would you prefer a definition that falsely describes some things as evolution when they're not and, at the same time, leaves out some things that should be included?

    That doesn't seem life a very good definition to me.

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  5. i agree, evolution is not a cause, it is an effect

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  6. Isn't "ascent with modification" a better descriptive term for going from simple to complex?

    How about "ascent with modification" combined with "trans-kind transformation"? People who breed dogs and cats say speciation has limits. How do you describe what is believed to go beyond natural limits of speciation and population groups? We could use a few examples of dats and cogs too. That would help evolution to be considered as fact, and not just "The" theory of evolution.

    Another thing: When you start this out "Millions of years ago," that just sounds too much like "Once upon a time, long ago and far away." That might be hurting the credibility factor. Just a thought.

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  7. Evolution does not necessarily lead from simple to complex, so no.

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