Fundementals of evo pt 2

Genetic drift – Random fluctuations in allele frequencies.
Heterozygosity – The frequency of heterozygotes in a population, defined by the formula H =
2p(1-p), where p is the frequency of one of two alleles.
Census size – When estimating population size, this is the number of individuals that you count,
regardless of whether they’re reproducing or not.
Effective population size (Ne) – The number of individuals in an ideal population (where all
individuals reproduce) in which the rate of genetic drift would be the same as in the actual
population.
Bottleneck – A severe, temporary reduction in population size.
Founder effect – Genetic drift in a small colonizing population.
Inbreeding depression – The resulting decline in fitness and fecundity that occurs when closely
related individuals reproduce; increases homozygosity in individuals that are more likely to share
the same recessive, deleterious alleles.
Neutral theory of molecular evolution – The great majority of mutations that are fixed are
effectively neutral with respect to fitness and are fixed by genetic drift.
Molecular clock – Evolutionary substitutions at the molecular level proceed at a constant rate,
so the degree of sequence difference between species can serve as a way to estimate relative
divergence times; can be calibrated to estimate actual times using data from the fossil record.