Ch. 21 The Evolution Of Populations

Question 1

Differences among individuals in the composition of their genes or other DNA sequences

Answer 1

Genetic variation

Question 2

Molecular level of DNA

Answer 2

Nucleotide variability

Question 3

Genetic variation at the whole-gene level

Answer 3

Gene variability

Question 4

A group of individuals of the same species that live in the same area and interbreed

Answer 4

Population

Question 5

Consists of all copies of every type of allele at every locus in all members of population

Answer 5

Gene pool

Question 6

Hardy Weinberg equation

Answer 6

P^2+2pq+q^2=1

Question 7

5 conditions of Hardy-Weinberg equilibrium

Answer 7

1. No mutations
2. Random mating
3. No natural selection
4. Extremely large population size
5. No gene flow

Question 8

Chance events causing allele frequencies to fluctuate unpredictably from one generation to the next; especially in small populations

Answer 8

Genetic drift

Question 9

A new population whose gene pool differs from the source population

Answer 9

Founder effect

Question 10

A severe drop in population size

Answer 10

Bottleneck effect

Question 11

Genetic drift is significant in…..

Answer 11

Small population

Question 12

Genetic drift can cause allele frequencies to change at …..

Answer 12

Random

Question 13

Genetic drift can lead to …

Answer 13

Loss of genetic variation within populations

Question 14

Genetic drift can cause harmful alleles to become..

Answer 14

Fixed

Question 15

The transfer of alleles into or out of a population due to the movement of fertile individuals or their gametes

Answer 15

Gene flow

Question 16

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

Answer 16

Relative fitness

Question 17

Conditions are favor individuals at one extreme of a phenotypic range

Answer 17

Directional selection

Question 18

Conditions favor individuals at both extremes of a phenotypic range over individuals w/ intermediate phenotypes

Answer 18

Disruptive selection

Question 19

Acts against both extreme phenotypes and favors intermediate variants

Answer 19

Stabilizing selection

Question 20

A difference in secondary sexual characteristics between males and females of the same species

Answer 20

Sexual dimorphism

Question 21

Occurs when natural selection maintains two or more forms in a population

Answer 21

Balancing selection

Question 22

The fitness of a phenotype depends on how common it is in the population

Answer 22

Frequency dependent selection

Question 23

Why natural selection cannot fashion perfect organisms?

Answer 23

1. Selections can act only on existing variations
2. Evolution is limited by historical constraints
3. Adaptions are often compromises
4. Chance, natural selection, and environment interact

Question 24

As a change in allele frequencies in a population over generations

Answer 24

Microevolution

Question 25

What makes evolution possible?

Answer 25

Genetic variation

Question 26

What three things can alter allele frequencies?

Answer 26

Natural selection, genetic drift, gene flow

Question 27

What is the only mechanism that consistently caused adaptive evolution?

Answer 27

Natural selection