More Evolution notes…

Darwin’s Theory of Evolution Species change and evolve over time due to the processes of natural selection and genetic variation

Populations evolve Gene pool: all of the alleles of a population’s genes Allelic Frequency: % of an allele in the gene pool

Genetic Equilibrium Genetic Equilibrium: a population in which the frequency of alleles remains the same Genetic Equilibrium can be disrupted by: Mutations: can result in a useful variation Genetic drift: the change of allelic frequencies caused by chance events Gene flow: the addition or subtraction of genes of a gene pool

Speciation Speciation: the evolution of a new species Speciation can occur by: Geographic isolation: when a physical barrier separates a population Reproductive isolation: when members of a population can no longer mate and produce fertile offspring Polyploidy: organism that contains a multiple of the normal set of chromosomes

Speciation Speciation can occur by (cont.): Gradualism: the idea that species originate through a gradual change in adaptations Punctuated equilibrium: speciation occurs relatively quickly and in rapid bursts

Emergence of new species Divergent evolution: when species that were once similar to an ancestral species diverge Adaptive radiation: when an ancestral species evolves into an array of species to fit a number of different habitats Convergent evolution: when distantly related organisms evolve similar traits

Types of Natural Selection Directional selection: natural selection that favors one of the extreme variations of a trait Stabilizing selection: natural selection that favors the average individuals in a population Disruptive selection: natural selection that favors either extreme of a trait’s variation

Aka: Disruptive

What type of evolution? Whale Sharks eat plankton with gills Baleen Whales eat plankton with baleen

What type of Evolution Sharks have cartilagenous skeletons Whales have bony skeletons