Chapter 23 Evolution of Populations

Question 1

Natural selection acts on _____, populations ______

Answer 1

individuals, evolve

Question 2

Microevolution

Answer 2

change in allele frequencies in a population over generations

Question 3

microevolution is evolution at its

Answer 3

smallest scale

Question 4

3 mechanisms cause allele frequencies

Answer 4

1) Natural selection
2) genetic drift
3) gene flow

Question 5

Natural selection

Answer 5

adapatation to the environment

Question 6

Genetic drift

Answer 6

chance events alter allele frequencies

Question 7

Gene flow

Answer 7

transfer of alleles between populations

Question 8

Genetic ___ makes evolution possible

Answer 8

variation

Question 9

Genetic Variation

Answer 9

variation in heritable traits among indivduals

Question 10

Phenotype

Answer 10

product of inherited genotype and environmental influences

Question 11

Hardy Weinberg Equation

Answer 11

expected genetic makeup for a population that is not evolving

Question 12

Hardy Weinberg Equilibrium

Answer 12

the population is not evolving, genotype and allele frequencies will be constant from generation to generation

Question 13

Gene pool

Answer 13

consists of all copies of every allele

Question 14

Hardy weinberg equation

Answer 14

p2 plus 2pq pis q2 equals 1

Question 15

hardy weinberg numbers

Answer 15

0.64+ 0.32+ 0.04

Question 16

Condtions for Hardy Equilbrium

Answer 16

No mutations, NO radnom mating, no natural selection, large pop size, no gene flow

Question 17

deviation from one of the required conditions can take a pop out of hardy equlibrium ?

Answer 17

true

Question 18

New mutations can alter allele frequencies

Answer 18

true

Question 19

No random mating can affect genotype freq but not allele freq

Answer 19

true

Question 20

3 major factors alter allele frequencies

Answer 20

natural selection

genetic drift

gene flow

Question 21

Natural selection can cause adaptive evolution,

Answer 21

a process in which traits that enhance survival or reproduction increase in frequency over time

Question 22

smaller sample means GREATER chance of random deviation from a predicted result

Answer 22

TRUE

Question 23

Genetic Drift

Answer 23

process in which chance events cause allele frequencies to fluctuate unpredictably from one gen to next-gen

Question 24

Founder-Effect

Answer 24

occurs when a few individuals become isolated from a larger population

Question 25

founder effect example

Answer 25

storm takes indivd. blown to a new island away from parent population

Question 26

Bottleneck Effect

Answer 26

drastic reduction in population size due to sudden changes in the environment

Question 27

4 Effects of Genetic Drift

Answer 27

Is significant in small populations can cause allele freq to change at random can lead to a loss of genetic variation within population can cause harmful alleles to become fixed

Question 28

Gene flow

Answer 28

movement of alleles among populations

Question 29

Gene flow ___ variation

Answer 29

reduces

Question 30

Gene flow can increase a populations ___

Answer 30

fitness

Question 31

Relative Fitness

Answer 31

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

Question 32

Directional Selection

Answer 32

favors individuals at one extreme end of the phenotypic range

Question 33

Stabilizing Selection

Answer 33

favors intermediate variants and acts against extreme phenotypes

Question 33

Disruptive Selection

Answer 33

favors individuals at both extremes of the phenotypic range

Question 34

Genetric drift and gene flow do NOT consistently increase the frew of allles that enhance survival and repdocution, both may increase or decrease the frequency of of beneficial alleles in a population

Answer 34

true

Question 35

Sexual selection

Answer 35

individuals with certain heritable traits are MORE likely to obtain mates than other individuals of the same sex

Question 36

sexual dimorphism

Answer 36

difference in secondary sexual characteristics between the sexes

Question 37

secondary characteristcs

Answer 37

size, color, behavior, etc

Question 38

Intrasexual selection

Answer 38

direct competition among individuals of one sex for mates of other sex

Question 39

Balancing Selection

Answer 39

preserves variation at some loci by maintaing stable frequencies of two or more phenotypes

Question 40

balancing selection includes (2)

Answer 40

frequency-dependent selection hetrozygote advantage

Question 41

hetrozygote advantage

Answer 41

heterozygotes have a higher fitness than both kinds of homozygotes