The Many Definitions of Evolution

I have a favorite definition of evolution [What Is Evolution?]. It's a definition based on population genetics and it helps us to decide on what counts as evolution and what doesn't. It's a minimal definition. There's more to evolution than that but you have to establish a boundary.

When you start discussing evolution you have to begin by establishing your definitions and declaring what version of evolutionary theory you support. This is especially important if you are debating extensions of evolutionary theory and it's even more important if you are debating a creationist. Creationists need to understand that evolution is both a Fact and a Theory, for example. If they don't understand that then they don't understand anything about evolution.

Creationists aren't the only problem. Even non-creationists get confused about evolution. Most don't know the difference between evolution and natural selection and that makes it difficult to talk about molecular evolution and a host of other topics. It's hard to explain junk DNA to an adaptationist and it's hard to show you why Michael Behe is wrong in The Edge of Evolution if you've never heard of Neutral Theory and random genetic drift.

Tomorrow in class we're going to talk about defining evolution and we're going to talk about the seriousness of misconceptions. If you have misconceptions about evolution then you can't really have a serious debate with a creationist—or with a fellow evolutionist.

I thought I'd point my students to a few of the definitions on the web. It's shocking to see how many different definitions of evolution there are and it's shocking to see how often websites ignore any mechanisms other than natural selection. You will be surprised at how many supposedly reputable sources get it wrong. It's no wonder everyone is confused.

Which ones do you like?

1. What is Evolution?
2. What Is Evolution?
Another curious aspect of the theory of evolution is that everybody thinks he understands it. I mean philosophers, social scientists, and so on. While in fact very few people understand it, actually, as it stands, even as it stood when Darwin expressed it, and even less as we now may be able to understand it in biology. Jacques Monod (1974)
3. What is evolution? Darwin's brilliant idea
4. WHAT IS EVOLUTION?
5. What Is Evolution Anyway?
6. Get Answers: Evolution
7. Understanding Science & Evolution
8. The Teaching of Evolution
9. What is evolution?
10. What is Evolution?
11. What Evolution Is and What It Isn’t
12. An introduction to evolution
13. What is Evolution?
14. Evolution Is Change in the Inherited Traits of a Population through Successive Generations
15. What is evolution?
16. What is Evolution?
17. Introduction: Evolution
18. What is evolution?
19. WHAT IS EVOLUTION?
20. What Is Evolution?

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