LIFE 102 Lecture Notes - Lecture 23: Allele Frequency, Biogeography, Crispr
Document Summary
Darwin was very impressed with the effects of heritable variation in the artificial selection. = breeding of plants and animals (including dogs and pigeons) For example, cauliflower, broccoli, cabbages, brussel sprouts, kale, and kohlrabi are the same species as brassica oleracea, a wild mustard. Darwinian evolution"s two postulates: new species can be derived from ancestral (pre-existing) species = descent with modification (adaptations), the mechanism for evolution is natural selection. There are individuals in a population that are better adapted to their environments and are therefore fitter = survival + reproduction. Fitness = survival (# survive to reproductive age) + reproduction (# of offspring). Extant: all species that exist today (only the top of darwin"s branching structure). Over time, a favored trait will predominate in a population = descent with modification . A population will change due to adaptation. The trait has been naturally selected, and the population has adapted to its environment, a better fit to the environment .
