final exam Flashcards
What are the five mechanisms of evolution?
Nonrandom mating, migration, genetic drift, natural selection, and mutation
Genetic Drift
a change in allele frequencies that occurs purely by chance
Nonrandom Mating
choosing mates based on location, physical mating traits, or other factors
The Founder Effect
small group of individuals establish a new settlement and mate amongst themselves
The Bottleneck Effect
sudden reduction in population size
Assortative (Nonrandom Mating)
preference for similar genotypes or phenotypes
Disassortative (Nonrandom Mating)
preference for different genotypes or phenotypes
Microevolution
small changes in a population over a short period of time
Macroevolution
large scale changes over a longer period of time (can include speciation)
Directional Selection
one extreme phenotype is the fittest and the environment selects against the others
Disruptive Selection
two extreme phenotypes are the fittest, and the environment selects against the other
Stabilizing Selection
extreme phenotypes are less fit than an optimal intermediate phenotype
Sexual Dimorphism
a difference in appearance between males and females
Homologous Structures
traits that are common amongst species and result from common ancestry (think forelimbs)
they have different purposes but are still present
Vestigial Structures
have no function but are found in related species
