m0-3 terms and definitions

abiotic conditions

physical limits to where a species can live (temperature, wind speeds, etc.)

biotic interactions

the relationships among organisms (competition, predation, etc.)

life history traits

adaptations that indicate how individuals allocate energy (growth, reproduction, etc.)

keystone species

one w/ a disproportionately large impact on the community it belongs to

gene

a molecule w/ hereditary info in code form

allele

gene variant

genotype

a listing of the alleles present in an individual

phenotype

an individual’s actual appearance or behavior

fitness

ability to produce viable offspring

mutation

any change in DNA; creates a new allele

adaptation

heritable trait to help an organism survive in its present environment

divergent evolution

two species evolve in different directions from a single point

convergent evolution

two species evolve separately to reach a common trait

homologous structures

parallel structures in diverse organisms that have a common ancestor (e.g. legs)

vestigial structures

useless structure (e.g. wisdom teeth)

evolution

a change in allele frequencies in a population over generations

adaptive radiation

species change genetically due to environmental influence

natural selection

heritable variation leading to differential reproductive success that results in changes in allele frequencies

directional selection

one phenotype is heavily favored and becomes more common in a short period of time

stabilizing selection

individuals w/ an average trait value have higher fitness than those on the extremes

adaptive evolution

natural selection; increases in beneficial alleles and decreases in detrimental alleles

diversifying selection

favors two or more distinct phenotypes (e.g. two different hair colors)

frequency-dependent selection

favors phenotypes that are either common (positive) or rare (negative)

sexual dimorphism

phenotypic differences between males and females of a species (in sexual selection)

handicap principle

only the fittest individuals can afford costly traits, making them more attractive to the opposite sex (in sexual selection)

good genes hypothesis

individuals develop impressive traits to show off to members of the opposite sex so the offspring can inherit these genes (in sexual selection)

honest signal

trait that gives a truthful impression of an individual’s fitness (in sexual selection)

descent w/ modification

the idea that species change over time, give rise to new species, and share a common ancestor