population genetics
the study of frequency and interactions of alleles and genes in population
normal distribution
a line graph showing the general trends in a set of data of which most values are near the mean
frequency
the proportion or ratio of a group that is of one type
genotype frequencies
focuses on the ratio of homozygous dominate:heterozygous:homozygous recessive
allele frequencies
focuses on the ratio of the dominant allele to the recessive allele of a particular characteristic
generate
produce; bring into being; cause to be
genetic equilibrium
the state in which the allele frequencies of a population remain in the same ratios from one generation to the next
Hardy-Weinberg principle
this idea predicts that the frequencies of alleles and genotypes in a population will not change unless at least one of 5 forces acts upon the population
gene flow
this occurs when genes are added to or removed from a population
nonrandom mating
occurs when any limits or preferences are placed on mate choices
genetic drift
this occurs when chance events cause rare alleles to be lost from one generation to the next
mutation
this can cause the addition of a new allele to a population
deviate
to turn aside; to diverge or differ
indirect force
natural selection acts on genotypes by removing unsuccessful phenotypes from a population
directional selection
a pattern of natural selection whose normal distribution peak moves in one direction along its range
stabilizing selection
a pattern of natural selection whose normal distribution peak becomes narrower
disruptive selection
a pattern of natural selection whose normal distribution peak undergoes a change that pushes it apart in different directions to form two new peaks
speciation
occurs when the net effects of evolutionary forces result in a population that has unique features and is reproductively isolated
reproductive isolation
a state in which two populations can no longer interbreed to produce future offspring
geography
the mechanism of isolation where a physical barrier may arise between populations which prevents interbreeding
ecological niche
the mechanism of isolation where divergence can occur due to populations using different niches
mating behavior and timing
the mechanism of isolation where two populations develop differences in how and/or when to reproduce
polyploidy
the mechanism of isolation where an organism has received a duplicate set of chromosomes by accident and become reproductively isolated from a population yet be able to reproduce itself via vegetative growth, self-fertilization, or find a polyploidy mate.
hybridization
the mechanism of isolation where two closely related species may come back into contact with each other and attempt to mate