Chapter 12

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

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

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 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

Sexual selection, such as competition between males for access to fertile females, frequently influences aspects of body form and can lead to ________. a. male aggression c. sexual dimorphism b. sexual reproduction 1\. both a and c

The persistence of the sickle allele at high frequency in a population is a case of ________.

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 _________.

Cladistics is based on ________. a. reconstructing evolutionary relationships b. grouping species on the basis of shared characters c. both a and b

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

In cladograms, sister groups are ________. a. inbred b. the same age c. represented by nodes d. members of 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 and leave a population d. evolutionary history e. occurs in different patterns f. burst of divergences from one lineage into a set of niches g. source of new alleles h. diagram of sets within sets