AP Biology: Evolution

structures in different species that are similar because of common ancestry

remnants of features that served important functions in the the organism's ancestors

the independent evolution of similar features in different lineages

the frequencies of alleles and genotypes in a population will remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work

the aggregate of all of the alleles for all of the loci in individuals in a population

a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring

a process in which organisms with certain inherited characteristics are more likely to survive and reproduce than are organisms with other characteristics

changes in the gene pool due to random events

when a individuals become isolated from a larger population, this smaller group may establish a new population whose gene pool differs from the source population

when there is a severe drop in population size, certain alleles may be overrepresented among the survivors, others may be underrepresented, and some may be absent altogether

the transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes

when conditions favor individuals exhibiting one extreme of a phenotypic range, thereby shifting the frequency curve for the phenotypic character in one direction or the other

when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes

acts against both extreme phenotypes and favors intermediate variants

a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates