honors bio unit i dont even know

evolution

a change in allele frequency over time

natural selection

process by which individuals that are best fit to their environment survive to reproduce and pass on their genes

variation

a difference in a physical trait

adaptation

a feature that allow an organism to better survive in its environment; can lead to genetic change in a population

biological fitness

ability to survive to reproductive age, find a mate, and produce offspring

overproduction

organisms produce more offspring than the environment can support

fossils

preserved remains of markings left by organisms that lived in the past

fossil record

chronological collection of life's remains in the rock layer

embryo

pre-birth stage of an organism's development

homologous structures

similar structures inherited from a common ancestor; can have different function

vestigial structures

structures that are reduced forms of function structures in organisms (do not really work anymore)

biochemistry

the macromolecules organisms are made out of (DNA/RNA, proteins, fats, carbohydrates)

gene pool

all of the alleles in all the individuals that make up a population

allele frequencies

measures how common an allele is in a population; can be calculated for each allele in a gene pool

mutation

random change in the DNA of a gene

HB: normal distribution

graphs as a bell-shaped curve

HB: directional selection

allele frequencies shift in one direction (selection favors phenotypes at one extreme)

HB: stabilizing selection

eliminates extremes; selection favors the intermediate phenoytpe

HB: disruptive selection

splits a population into two groups; selection favors both extreme phenotypes

gene flow

the movement of alleles between populations; occurs when individuals join new populations and reproduce

genetic drift

any change in the allele frequencies in a population that is due to chance

bottleneck effect

occurs when an event drastically reduces population size; usually rebounds with individuals having many of the same alleles

founder effect

occurs when a small amount of organisms from a population become isolated from other populations

sexual selection

occurs when certain traits increase mating success

species

a group of organisms capable of interbreeding and producing fertile offspring

speciation

some members of a sexually reproducing population change so much that they can no longer produce fertile offspring with members of the original population

reproductive isolation

prevents gene flow among populations; condition caused by some reproductive barrier that keeps two species from interbreeding

behavioral isolation

differences in courtship/mating behaviros, leading to difficulty attracting mates

geographic isolation

different mating places or physical barrier divides the population

temporal isolation

mate at different times of year

convergent evolution

unrelated species evolve with similar traits; environments are far apart, but the ecology and climate are similar

divergent evolution

diversification of a species into a number of different species, often over a relatively short period of time

coevolution

species evolve in close relationship with each other

extinction

the elimination of a species from Earth

taxonomy

identification, naming, and classification of species

binomial nomenclature

two-part scientific naming system

cladogram

a diagram used to represent relationships between a group of organisms

clade

group of species that shares a common ancestor