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

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

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 b. sexual reproduction c. sexual dimorphism d. 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 cladograms, sister groups are __________. a. inbred b. the same age c. represented by nodes d. members of the same family

Match the evolution concepts. $$ \text {________gene flow } \quad \quad\quad\quad\quad \text {a. can lead to interdependent species} $$ $$ \text {________natural selection } \quad \quad\quad\quad\quad \text {b. changes in a population's allele frequencies due to chance alone} $$ $$ \text {________mutation} \quad \quad\quad\quad\quad \text {c. alleles enter and leave a population} $$ $$ \text {________genetic drift} \quad \quad\quad\quad\quad \text {d. evolutionary history} $$ $$ \text {________adaptive radiation} \quad \quad\quad\quad\quad \text {e. occurs in different patterns} $$ $$ \text {________coevolution} \quad \quad\quad\quad\quad \text {f. burst of divergences from one lineage into a set of niches} $$ $$ \text {________phylogeny }\quad \quad\quad\quad\quad \text {g. source of new alleles} $$ $$ \text {________cladogram }\quad \quad\quad\quad\quad \text {h. diagram of sets within sets} $$