Evolution
change in a species overtime; process of biological change by which descendents come to differ from their ancestors.
Theory
Prposed to be explanation for a wide variety of observations and experiemental results.
Fossil
trace of an organism from the past.
Artificial selection
Process by which humans modify a species by breeding it for certain traits.
Fitness
measure of an organism's ability to survive and produce offspring relative to other members of a population.
Adaptation
inherited trait that is selected for overtime because it allows organisms to better survive in their environment.
natural selection
by which individuals that have inherited beneficial adaptations produce more offspring on average than do others individuals.
Homologous structure
body part that is similar instructure on different organisms but performs different functions.
vestigal organ
remnants of an organ or structure that functioned in a earlier ancestor.
RelaTIVE FREQUENCY
estimate of the age of a fossil based on the location of fossils in strata.
Gene Pool
collection of alleles found in all of the individuals of a population.
Polygenic trait
trait that is produced by two or more genes.
Directional selection
pathway of natural selection in which one uncommon phenotypes selected over a more common phenotype.
stabilizing selection
pathway of natural are selected over phenotypes at both extremes.
disruptive selection
pathway of natural selection in which two opposite, but equally uncommon, phenotypes are selected oven the most common phenotype.
genetic drift
change in allele frequencies due to chance alone,occuring most commonly in small populations.
hardy-weinburg equilibrium
condition in which a population allele frequencies for a given trait do not change from generation to generation.
speciation
evolution of two or more species from one ancestral species.
reproductive isolation
final stage in speciation which members of isolated populations are either no longer able to mate or nothing able to produce viable offsprings.
Behavioral Isolation
isolation between population due to