Chapter 17

Individuals don't evolve, _____________ do.

Biologists define evolution as ______________. a. purposeful change in a lineage b. heritable change in a line of descent c. acquiring traits during the individual's lifetime

______________ is the original source of new alleles. a. Mutation b. Natural selection c. Genetic drift d. Gene flow e. All are original sources of new alleles

Evolution can only occur in a population when ____________. a. mating is random b. there is selection pressure c. neither is necessary

A fire devastates all trees in a wide swath of forest. Populations of a species of tree-dwelling frog on either side of the burned area diverge to become separate species. This is an example of ____________.

Stabilizing selection tends to ____________ (select all that apply). a. eliminate extreme forms of a trait b. favor extreme forms of a trait c. eliminate intermediate forms of a trait d. favor intermediate forms of a trait e. shift allele frequencies in one direction

Disruptive selection tends to _____________ (select all that apply). a. eliminate extreme forms of a trait b. favor extreme forms of a trait c. eliminate intermediate forms of a trait d. favor intermediate forms of a trait e. shift allele frequencies in one direction

Directional selection tends to ____________ (select all that apply) a. eliminate extreme forms of a trait b. favor an extreme form of a trait c. eliminate intermediate forms of a trait d. favor intermediate forms of a trait e. shift allele frequencies in one direction

Sexual selection, such as occurs when males compete for access to fertile females, frequently influences aspects of body form and can lead to ______________. a. male/female differences b. male aggression c. exaggerated traits d. all of the above

The persistence of malaria and sickle-cell anemia in a population is a case of ______________. a. bottlenecking b. balanced polymorphism c. natural selection d. artificial selection e. both b and c

___________ tends to keep populations of a species similar to one another. a. Genetic drift b. Gene flow c. Mutation d. Natural selection

In evolutionary trees, each node represents \(a(n)\) ______________. a. single lineage b. extinction c. point of divergence d. adaptive radiation

In cladograms, sister groups are _____________. a. inbred b. the same age c. represented by nodes d. in the same family

Match the evolution concepts _________ gene flow _________ natural selection _________ mutation _________ genetic drift _________ adaptive radiation _________ coevolution _________ phylogeny _________ cladogram a. can lead to interdependent species b. changes in a population's allele frequencies due to chance alone c. alleles enter or leave a population d. evolutionary history e. occurs in different patterns f. burst of divergences from one lineage into many g. source of new alleles h. diagram of sets within sets