natural selection

reproduction of individuals with favorable traits that survive environmental changes because of those traits. this leads to evolutionary change

mutation

a change in DNA. the source of new alleles or new genetic variation in any population

sexual reproduction

2 parents reproduce unique combos of alleles assemble to produce the unique geno. and phenotypes in each off-spring.

adaptation

a heritable trait that helps an organism's survival and reproduction in its present environment

divergent evolution

2 species that evolve in diverse directions from a common point

homologous structures

when evolution changes bones shape and size in different species but they have maintained the same layout

vestigal structures

structures that exist in organisms with no apparent functions. Appear to be residual parts from a past common ancestor.

embryology

study of anatomy of an organism's development to its adult form. provides evidence of relatedness between now widely divergent groups of organisms.