Biology Chapter 13 Vocab

Question 1

Adaptation

Answer 1

An inherited character that enhances an organism’s ability

to survive and reproduce in a particular environment.

Question 2

Artificial Selection

Answer 2

The selective breeding of domesticated plants and

animals to promote the occurrence of desirable traits.

Question 3

Balancing Selection

Answer 3

Natural selection that maintains stable frequencies

of two or more phenotypic forms in a population.

Question 4

Bottleneck effect

Answer 4

Genetic drift resulting from a drastic reduction
in population size. Typically, the surviving population is no longer
genetically representative of the original population.

Question 5

Directional selection

Answer 5

Natural selection in which individuals at one
end of the phenotypic range survive and reproduce more successfully
than do other individuals.

Question 6

Disruptive selection

Answer 6

Natural selection in which individuals on
both extremes of a phenotypic range are favored over intermediate
phenotypes.

Question 7

Evolution

Answer 7

Descent with modification; the idea that living species are
descendants of ancestral species that were different from present-day
ones; also, the genetic changes in a population from generation to
generation.

Question 8

Fossil record

Answer 8

The chronicle of evolution over millions of years of geologic
time engraved in the order in which fossils appear in rock strata.

Question 9

Founder effect

Answer 9

Genetic drift that occurs when a few individuals
become isolated from a larger population and form a new population
whose gene pool is not reflective of that of the original population.

Question 10

Gene flow

Answer 10

The transfer of alleles from one population to another as a

result of the movement of individuals or their gametes.

Question 11

Gene pool

Answer 11

All copies of every type of allele at every locus in all members
of the population.

Question 12

Genetic drift

Answer 12

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

Effects of genetic drift are most pronounced in small populations.

Question 13

Hardy-Weinberg equilibrium

Answer 13

The state of a population in which
frequencies of alleles and genotypes in a population remain constant
from generation to generation, provided that only Mendelian segregation
and recombination of alleles are at work.

Question 14

Heterozygote advantage

Answer 14

Greater reproductive success
of heterozygous individuals compared with homozygotes; tends
to preserve variation in gene pools.

Question 15

Homologous structures

Answer 15

Structures in different species

that are similar because of common ancestry.

Question 16

Homology

Answer 16

Similarity in characters resulting from a

shared ancestry.

Question 17

Microevolution

Answer 17

A change in a population’s gene pool over

generations.

Question 18

Mutation

Answer 18

A change in the genetic information of a cell; the ultimate
source of genetic diversity. A mutation also can occur in the DNA or
RNA of a virus.

Question 19

Natural selection

Answer 19

A process in which individuals with certain inherited
traits are more likely to survive and reproduce than are individuals
that do not have those traits.

Question 20

Population

Answer 20

A group of individuals belonging to one species and living

in the same geographic area.

Question 21

Relative fitness

Answer 21

The contribution an individual makes to the gene pool
of the next generation, relative to the contributions of other individuals
in the population.

Question 22

Sexual dimorphism

Answer 22

Marked differences between the

secondary sex characteristics of males and females.

Question 23

Sexual selection

Answer 23

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

Question 24

Stabilizing selection

Answer 24

Natural selection that favors intermediate variants

by acting against extreme phenotypes.

Question 25

Vestigial structure

Answer 25

A feature of an organism that is a historical remnant

of a structure that served a function in the organism’s ancestors.