Zimmerman ap bio unit 8 evolution

covergent evolution

process by which unrelated species evolve similar physical characteristics bc they have similar lifestyles

analogous structures

separate evolution of structures, but similar functions

homologous structures

shared common source of structure but different function

natural selection

does not operate on individuals

microevolution

change in allele frequency of a population

population genetics

emphasise extensive variation in a population

population

localised group of individuals belonging to same species

variation

raw material of natural selection

mutation

random changes to dna

sex

mixing alleles, recombining of alleles, spreads variation

genepool

a collection of alleles in the population

allele frequency

how common is that allele in the population

gene flow

movement of individuals and alleles in & out of a population

intersexual selection

other sex is deciding who gets to mate- ex. peacocks

intrasexual selection

one sex decides who gets to mate- ex. deers

phylogeny

a diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor

cladogram

sympatric speciation

he evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region

adaptive radiation

The evolution of numerous species, such as Darwin's finches, from a single ancestor

ecological isolation

different habitat preferences, decreased chance of mating

mechanical isolation

physical incompatibility, prezygotic

gametic isolation

fertilisation does not occur, prezygotic

temporal isolation

prezygotic, different mating seasons

hybrid breakdown

post zygotic, grandchild is sterile

directional selection

one extreme phenotype is favored over both the other extreme and moderate phenotypes.

diversifying selection

describes changes in population genetics in which extreme values for a trait are favored over intermediate values

stabilising selection

medium traits are favoured

neutral variation

whether you carry allele A or allele B does not affect your fitness.

polymorphism

the occurrence of two or more clearly different morphs or forms, also referred to as alternative phenotypes, in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating).