Galapagos Diary: Neo-Darwinism Lecture, Part 1
Here are some of my notes on the lecture, which also includes a brief history, that I will not reproduce here, of the evolution (sorry) of Darwin’s ideas through Mendel’s observations, the Neo-Darwinian Synthesis, and Punctuated Equilibrium, up to the present day:
The title of Darwin’s sixth edition of On the Origin of Species by Means of Natural Selection should have included and All Sorts of Other Things. The first edition is closer than the sixth and last edition to our modern view of Darwinism. Darwin was pressured into adding the words “breathed by the Creator into,” but the first edition the phrase was just “breathed into.”
Darwin explained both diversity and adaptation. Natural selection is the only theory that can, in principle, explain adaptation. The only “rivals” are design and Lamarckanism.
The neutral theory doesn’t explain adaptation. The premise is that many mutations are neutral – not useless, but equivalent to the original codon. Any amino acid can be coded for by more than one codon, resulting in synonymous mutation.
Synonymous mutation equals zero mutation.
The majority of evolution is neutral. However, phenotypic change is not neutral to a field naturalist (ethologist).
The coding of an amino acid effects a phenotypic change only insomuch as it affects the shape of the protein, which has an enzymatic effect.