topic 10 evolution

evolution

change over time, change in the frequency of heritable phenotypes and the alleles that govern them

populations

units of evolution

microevolution

allelic + phenotypic frequency changes in populations

macroevolution

speciation (species change), extinction, water < - > land transformations

mutation

mitotic/meiotic DNA replication errors, recombination/crossover errors, natural accidents, or induration by mutagens

what are the two types of mutations?

base substitutions, INDELS

base substitutions

in protein coding genes, such mutations can be silent, missense, and nonsense

silent mutation

base substitution/change in DNA that does NOT change the funciton of the protein/amino acid

missense mutation

base substitution/change in DNA that DOES affect the amino acid/protein function

nonsense mutation

base substitution/change in DNA that STOPS the amino acid sequence

INDELS

insertions or deletions

insertion mutation

a base gets inserted/added

deletion mutation

a base gets deleted/removed

genetic drift

chance driven changes in trait frequencies

where do genetic drifts occur more often?

small populations

nonrandom mating

when probability of one individual mating with another in population is not random

nonrandom mating at organism level

geographical proximity has a big influence on mating

nonrandom mating at individual trait level

mating may be random with respect to handedness, but likely nonrandom with respect to others (sexual selection)

natural selection

differential “fitness” or organisms based on their heritable traits

directional selection

pushing it towards a direction (further down/up x/y)

stabalizing selection

pushing it towards a middle ground (bell curve)