Wednesday, February 20, 2008

Evolution Misconceptions and Corrections

The internets have thrown forth a helpful list of 15 common misconceptions about evolution. It's a quick read and I love the illustrations, one of which is borrowed here.

One of the misconceptions deserves some attention:

Evolution is a theory about the origin of life

The theory of evolution primarily deals with the manner in which life has changed after its origin. While science is interested in the origins of life (for example the composition of the primeval sludge from which life might have come) but these are not issues covered in the area of evolution. What is known is that regardless of the start, at some point life began to branch off. Evolution is, therefore, dedicated to the study of those processes.
I would have agreed with this characterization -- I would have insisted that evolution, properly understood, is distinct from abiogenesis -- but someone who knows a lot more about it, PZ Myers, has this to say:
"Evolution is a theory about the origin of life" is presented as false. It is not. I know many people like to recite the mantra that "abiogenesis is not evolution," but it's a cop-out. Evolution is about a plurality of natural mechanisms that generate diversity. It includes molecular biases towards certain solutions and chance events that set up potential change as well as selection that refines existing variation. Abiogenesis research proposes similar principles that led to early chemical evolution. Tossing that work into a special-case ghetto that exempts you from explaining it is cheating, and ignores the fact that life is chemistry. That creationists don't understand that either is not a reason for us to avoid it.
OK! Corrected misconception corrected! Or something like that -- the logical curly-Q's start to elude me. PZ Myers is a committed defender of evolution and the proper boundaries of evolutionary theory, and what he says here agrees with the famous passage in Richard Dawkins' The Selfish Gene, when he is setting up the concept of the meme:
I am an enthusiastic Darwinian, but I think Darwinism is too big a theory to be confined to the narrow context of the gene ... What, after all, is so special about genes? The answer is that they are replicators.
Genes are just a special case of replicators, just one of the "natural mechanisms that generate diversity," and the one that accounts for the diversity of species on earth. But the process by which simpler chemical replicators gave rise to genes is within the scope of modern evolutionary theory.

Cf. cdk007's many useful and informative videos on evolution, abiogenesis, creationism, probability, chemistry, and related topics.

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