Chapter 1. Insufficient Explanations

In my first genetics course, I was hoping to understand the secrets of evolution. The first half of the course was on molecular genetics. We studied little puzzle pieces and recipes made up of DNA. The second half of the course, population genetics, seemed irrational. How could evolution be explained through some mathematical equations based on impossible assumptions? General definitions from a biology text are included here, including adaptation, natural selection and fitness. A lot of theoretical ecology had the same problem with telling stories about adaptation that were too much like Kipling’s “how the elephant got his trunk,” except that in this version, selection wipes out those with unfit trunk lengths.

Many students have heard the story of the pepper moth – the common form was white with black spots until the trunks of the birch trees became blackened with Industrial Revolution soot. The dark brown form of the moth was harder for birds to see under these conditions, so it became more common as the white form declined in numbers. Students often hear this story as an example of evolution, but it is not, since nothing new came to be. Natural selection is a variation-decreasing force acting on random mutations, but is that all there is to it? Maybe I was missing something, but neo-Darwinian theory didn’t seem to offer a very good explanation for multicellular organisms or the diversity of species. There’s no pretending “intelligent design” is any sort of science, but that doesn’t mean natural selection can’t be questioned, or even rejected.

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