Chapter 13

Question 1

Hardy-Weinberg Equilibrium

Answer 1

the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors

Question 2

Homology

Answer 2

the existence of shared ancestry between a pair of structures, or genes, in different species

Question 3

Microevolution

Answer 3

the change in allele frequencies that occur over time within a population

Question 4

Modern Synthesis

Answer 4

a consolidation of the results of various lines of investigation from the 1920s through the 1950s that supported and reconciled the Darwinian theory of evolution and the Mendelian laws of inheritance in terms of natural selection acting on genetic variation.

Question 5

Natural Selection

Answer 5

any characteristic of an individual that allows it to survive to produce more offspring will eventually appear in every individual of the species

Question 6

Population

Answer 6

The total number of inhabitants constituting a particular race, class, or group in a specified area.

Question 7

Vestigial Structures

Answer 7

A structure in an organism that has lost all or most of its original function in the course of evolution

Question 8

Biogeography

Answer 8

The study of the geographic distribution of species.

Question 9

Bottleneck Effect

Answer 9

Genetic drift resulting from a drastic reduction in population size.

Question 10

Comparative Anatomy

Answer 10

The comparison of body structures in different species.

Question 11

Directional Selection

Answer 11

Natural selection that acts in favor of the individuals at one end of a phenotypic range.

Question 12

Evolution

Answer 12

Decent with modification; genetic change in a population or species over generations; the heritable changes that have produced Earth’s diversity of organisms.

Question 13

Evolutionary Adaptation

Answer 13

A population’s increase in the frequency of traits suited to the environment.

Question 14

Sexual Selection

Answer 14

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

Question 15

evolutionary tree

Answer 15

a branching diagram that reflects a hypothesis about evolutionary relationships between groups of organisms

Question 16

fossil record

Answer 16

the ordered sequence of fossils as they appear in the rock layers, marking the passing of geologic time

Question 17

fossils

Answer 17

a preserved imprint or remains of an organism that lived in the past

Question 18

founder effect

Answer 18

the genetic drift resulting from the establishment

of a small, new population whose gene pool differs from that of the parent population

Question 19

gene flow

Answer 19

the gain or loss of alleles from a population by the movement of individuals or gametes into or out of the population

Question 20

gene pool

Answer 20

all the genes in a population at any one time

Question 21

genetic drift

Answer 21

a change in the gene pool of a population due to chance

Question 22

sexual dimorphism

Answer 22

distinction in appearance based on secondary sex characteristics, noticeable differences not directly associated with reproduction or survival

Question 23

stabilizing selection

Answer 23

natural selection that favors intermediate variants by acting against extreme phenotypes