Chapter 17: Evolution of Populations

Question 0

Allele frequency

Answer 0

Number of times that an allele occurs in a gene pool compared with the number of alleles in that pool for the same gene

Question 1

Gene pool

Answer 1

all of the genes, including all the different alleles for each gene, that are present in a population at any one time

Question 2

Single-gene trait

Answer 2

trait controlled by one gene that has two alleles

Question 3

polygenic trait

Answer 3

trait controlled by two or more genes

Question 4

Directional selection

Answer 4

Form of natural selection in which in which individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

Question 5

Stabilizing Selection

Answer 5

Form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve

Question 6

Disruptive Selection

Answer 6

Natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve

Question 7

Genetic Drift

Answer 7

Random change in allele frequency caused by a series of chance occurrences that cause an allele to become more or less common in a population

Question 8

Bottleneck effect

Answer 8

A change in allele frequency following a dramatic reduction in the size of a population

Question 9

Founder effect

Answer 9

Change in allele frequencies as a result of the migration of a small subgroup of a population

Question 10

Genetic equilibrium

Answer 10

Situation in which allele frequencies in a population remain the same

Question 11

Hardy-Weinberg Principle

Answer 11

Principle that states that allele frequencies in a population remain constant unless one or more factors (non-random mating, small population, selection, mutations, and migrating)

Question 12

Sexual Selection

Answer 12

When individuals select mates based on heritable traits

Question 13

Species

Answer 13

group of similar organisms that can breed and produce fertile offspring

Question 14

Speciation

Answer 14

Formation of a new species

Question 15

Reproductive isolation

Answer 15

Separation of a species or population so that they no longer interbreed and evolve into two separate species

Question 16

Behavioral isolation

Answer 16

Form of reproductive isolation in which two populations develop differences in courtship rituals or other behaviors that prevent them from breeding

Question 17

geography isolation

Answer 17

Form of reproductive isolation in which two populations are separated by geographic barriers such as rivers, mountains, or bodies of water, leading to the formation of two separate subspecies

Question 18

Temporal Isolation

Answer 18

Form of reproductive isolation in which two or more species reproduce at different times

Question 19

Molecular Clock

Answer 19

Method used by researchers that uses mutation rates in DNA to estimate the length of time that two species have been evolving independently