Chapter 16

Individuals don't evolve, ___ do.

Biologists define evolution as ___. a. the origin of a species b. heritable change in a line of descent c. acquiring traits during the individual's lifetime d. all of the above

___ is the original source of new alleles. a. Mutation b. Natural selection c. Genetic drift d. Gene flow e. All give rise to new alleles

Natural selection may occur when there are ____. a. differences in forms of traits b. differences in survival and reproduction among individuals that differ in one or more traits c. both a and b

Directional selection ___. a. eliminates uncommon forms of alleles b. shifts allele frequencies in a consistent direction c. favors intermediate forms of a trait d. works against adaptive traits

Disruptive selection ___. a. eliminates uncommon forms of alleles b. shifts allele frequencies in a consistent direction c. doesn't favor intermediate forms of a trait d. both b and \(c\)

___ tends to reduce allelic differences among populations of a species. a. Genetic drift b. Gene flow c. Mutation d. Natural selection

Match the evolution concepts. $$ \text { gene flow } \quad \quad\quad\quad\quad \text { a. source of new alleles } $$ $$ \text { natural selection } \quad \quad\quad\quad\quad \text { b. changes in a population's allele frequencies due to chance alone } $$ $$ \text { mutation } \quad \quad\quad\quad\quad \text { c. allele frequencies change owing to immigration, emigration, or both } $$ $$ \text { genetic drift } \quad \quad\quad\quad\quad \text { d. outcome of differences in survival, reproduction among individuals that vary in forms of shared traits } $$