Notes

Main idea 1: Descent with modification - species will change overtime, will give birth to new species and share common ancestors.
Main idea 2: Modification by natural selection (adaptation in species leads to new species)
Species: a group of organisms that can reproduce
Evolution - species change overtime.
Divergent evolution (speciation) - organisms evolve from common ancestors. Can be shown through homologous structures.
Convergent evolution - organisms have similar features but don't have common ancestors. Can be shown through analogous structures (same functions but different ancestors)
Homologous structures are from the same location and show similar structures.
Two organisms can be both analogous and homologous if some structures have a common ancestor and some structures evolved differently compared to others.
Microevolution - change in allele frequencies by:
Natural selection - adaptation leads to favor in one gene, and its frequency will go up
Genetic drift - chance events that alter allele frequencies.
Gene flow - Movement of individuals in and out of population (migration)
GEOGRAPHIC ISOLATION CAUSES REPRODUCTIVE ISOLATION CAUSES SPECIATION
Crossing over, independent assortment, fertilization and mate selection lead to variation in populations via gametes.
Population - a group of same species in the same area
Gene pool - total genetic makeup
The hardy Wienberg equilibrium is a situation where there is a stable environment where there will be no evolution. Is used to test for changes in gene pool. A large population, random mating, no gene flow, no mutation, no natural selection.
The hardy Wienberg equation:
recessive allele frequency = q
dominant allele frequency = p
recessive phenotype = q^2
homozygous dominant = p^2
heterozygous = 2pq
Genetic drift pt2 - change in allele frequencies, usually reduces genetic variation (inbreeding is a cause)
Bottleneck effect - a random catastrophic event that kills most of the population which will alter the populations gene pool.
Founder effect - A new population breeds with a small established population
Gene flow pt2 - movement of genes in and out of different populations cause change in allele frequencies.
Types of Natural Selection:
Directional - the favored individuals are at one extreme of the phenotypic range.
Disruptive - the favored individuals are at both extremes.
Stabilizing - the favored individuals are in the middle, strengthening the intermediate phenotype.