AP Bio Reading Log Vocab

acquired characteristics

modifications caused by an individual’s environment that can be inherited by its offspring

adaptation

a heritable trait that helps the survival and reproduction of an organism in its current environment.

adaptive radiation

when a single ancestral species gives rise to many new species

allopatric speciation

type of speciation involving geographic separation of populations

behavioral isolation

when pressure or absence of a specific behavior prevents reproduction from taking place

convergent evolution

when similar traits with the same function evolve in multiple species exposed to the same pressures.

dispersal

when a few members of a species move to a new geographical area

divergent evolution

Two species that evolve in diverse directions from a common point.

gametic barrier

a prezygotic barrier when differences in gametic cells prevent fertilization.

gradual speciation model

species diverge gradually over time in small steps

habitat isolation

when populations of a species move to a new habitat and take up residence in a place that no longer overlaps with other populations of the same species.

homologous structures

structures in organisms that share the same basic form

hybrid

when two different species produce an offspring

hybrid zone

an area where two closely related species continue to interact and reproduce forming hybrids

natural selection

“survival of the fittest” -- creatures with advantageous mutations love long and reproduce, those without it die and do not reproduce

polyploidy

gametes with extra chromosomes

postzygotic barrier

blocks reproduction after fertilization occurs

prezygotic barrier

blocks reproduction before fertilization occurs

punctuated equilibrium

when a new species undergoes changes rapidly from the parent species and then remains largely unchanged for a long time after

reinforcement

when hybrids are less fit, reproduction diminishes over time, nudging the two species to diverge further

reproductive isolation

the inability to interbreed

speciation

formation of new species

species

group of populations that interbreed and produce valid offspring

sympatric speciation

type of speciation occuring due to mechanisms that occur within a shared habitat

temporal isolation

differences in breeding schedules that can act as a prezygotic barrier

theory of evolution

the unifying theory of biology -- all life has evolved from a common ancestor

variation

differences among individuals in a population

vestigial structure

residual parts from a past common ancestor

adaptive evolution

increase in frequency of beneficial alleles and decrease in deleterious alleles due to selection

allele frequency (gene frequency)

rate at which a specific allele appears within a population

assortative mating

when individuals tend to mate with those who are phenotypically similar to themselves

bottleneck effect

magnification of genetic drift as a result of natural events or catastrophes

directional selection

selection that favors phenotypes at one end of the spectrum of existing variation

diversifying selection

selection that favours two or more distinct phenotypes

evolutionary fitness (Darwinian fitness)

individuals ability to survive and reproduce

Fitness

measure of successful reproduction, the passing on alleles to the next generation

founder effect

event that initiates an allele frequency changing part of the population, which is not typical of the original population.

frequency-dependant selection

selection that favors phenotypes that are either common or rare

gene flow

flow of alleles in and out of a population due to migration of individuals or gametes

gene pool

all of the allele carried by all the individuals in the population

genetic drift

effect of chance on a populations gene pool

genetic structure

distribution of the different possible genotypes in a population

genetic variance

diversity of alleles carried by all the individuals in the population

genotype frequency

the proportion of a specific genotype in a population relative to all other genotypes for those genes that are present in the population

geographical variation

differences in the phenotypic variation between populations that are separated geographically

good genes hypothesis

theory of sexual selection that argues individuals develop impressive ornaments to show off their efficient metabolism or ability to fight disease.

handicap principle

theory of sexual selection that argues only the fittest of individuals can afford costly traits

Hardy-Weinburg princible of equalibrium

a stable, non-evolving state of a population in which allelic frequencies are stable over time.

heritability

fraction of population variation that can be attributed to its genetic variance

honest signal

trait that gives a truthful impression of an individuals fitness

inbreeding

mating of closely related individuals

inbreeding depression

increase of abnormalities and disease in inbreeding populations

macroevolution

broader scale of evolutionary changes seen over paleontological time.

microevolution

changes in a populations genetic structure

modern synthesis

overarching evolutionary paradigm that took shape by the 1940s and is generally accepted today

homology

similarity in characteristics resulting from a shared ancestry (opposite of analogy)

maximum parsimony

when there are multiple explanations, one should consider the one that is simplest and most obvious, with least amount of steps

analogy

(opposite of homology) similarities due to convergent evolution and not common ancestry.

binomial nomenclature

genus and species

branch point

point on phylogenetic tree where one species branches into two

cladistics

system that uses homologous traits to descripe p

cladogram

like phylogenetic tree but no indication of time or level of differences

eukaryote-first hypothesis

everything began with eukaryotes and then prokaryotes branched off from them.