In this episode we place two important revisions on top of the classical understanding of evolution.
The first is Marie West-Eberhard’s Theory of Genetic Accommodation
Organisms display phenotypic plasticity — the ability to display different phenotypes depending upon environment.
The theory of genetic accommodation says that novel traits induce novel traits, gene networks are expressed in new ways which result in the creation of new traits.
Selection favors alleles which make this response more reliable.
Genes are “followers” not “leaders”, the creation of novel traits is driven by the environment, not random mutation.
The second is Motoo’s Neutral Theory of Evolution
Most mutations are harmless and therefore do not affect an organism’s fitness, this means the fate of the allele is not left up to selection.
An allele becomes “fixed” (either in 0 or 100% of the population) based on the probability of a random walk 1/2N.
Because the rate of mutation tends to be constant, we can look at the number of neutral allele’s between two populations to determine how long ago they drifted apart, otherwise known as the molecular clock.
