BIOL 1911 Chapter 23: Biology Chapter 23.docx
Document Summary
Quick review of key concepts (1) selection acts on individuals. (2) but evolution occurs at population level. (3) evolution is not progressive". (4) not all traits are adaptive. (5) genetic constraints limit evolutionary pathways. It must be realized that natural selection is not the only mechanism of evolution. Each of the four processes listed below has different consequences. (1) natural & sexual selection (2) genetic drift (3) gene flow (4) mutation. The hardy-weinberg principle acts as a null hypothesis when researchers want to test whether evolution or nonrandom mating is occurring at a particular gene within a gene pool. Godfrey hardy and wilhelm weinberg wanted to know what happened in an entire population (gene pool), when all of the individuals. They started with the simplest situation, a gene with two. Because there are only two alleles, p + q. In this situation, three genotypes are possible: a1a1, a1a2, and a2a2. The frequency of the a1a1 genotype is p2.
