Chapter 24

Question 1

The most common type of genetic change that causes polymorphism in a population is….

Answer 1

A single nucleotide substitution

Question 2

Hardy Weinberg equation characterizes the allele and genotype frequencies….

Answer 2

Of a population that is very large and not evolving

Question 3

In the hardy Weinberg equation what portion represents the frequency of individuals that do not exhibit a recessive disease but are carriers of a recessive allele?

Answer 3

2pq

Question 4

What is not likely to have a major influence on allele frequencies?

Answer 4

In-breeding and mutation

Question 5

Mutations….

Answer 5

Provide the source for genetic variation, but other evolutionary factors are more important in determining allele frequencies in a population

Question 6

Most of genetic variation in population is due to what?

Answer 6

Neutral mutations that do not affect reproductive success

Question 7

Effect of inbreeding…

Answer 7

Decrease in fitness due to an increased frequency of recessive genetic diseases

Question 8

Population genetics

Answer 8

Study of genes and genotypes in a population

Question 9

Population

Answer 9

Groups of individuals of the same species that occupy the same environment and can interbreed

Question 10

Gene pool

Answer 10

All of the alleles for every gene in a population

Question 11

Polymorphism

Answer 11

Refers to two or more variants of a character in a population

Question 12

Monomorphic gene

Answer 12

Exists as a single allele

Question 13

Allele frequency

Answer 13

Number of copies of a specific allele/ total number of alleles in a population

Question 14

Genotype frequency

Answer 14

Number of individuals within a given genotype/ total number of individuals in population

Question 15

Hardy Weinberg equation

Answer 15

P2+2pq+q^2=1

Question 16

Hardy Weinberg equilibrium

Answer 16

-allele and genotype frequencies won’t change if no mutations occur, no natural selection occurs, population size is very large, migration does not occur, and mating is random

Question 17

Fitness

Answer 17

Relative likelihood that a genotype will contribute to gene pool of next generation
**measure of reproductive success

Question 18

Directional selection

Answer 18

Process by which one extreme of a phenotypic Distribution is favored

Question 19

Stabilizing selection

Answer 19

Process by which an intermediate phenotype is favored

Question 20

Diversifying (disruptive) selection

Answer 20

Process by which two or more phenotype are favored. Population with heterogenous environments is good example

Question 21

Balancing selection

Answer 21

Maintains genetic polymorphism

Heterozygote advantage and negative frequency-dependent selection

Question 22

Genetic drift

Answer 22

Changes in allele frequencies over time due to chance events

Question 23

Genetic drift promotes…

Answer 23

Neutral genetic changes that do not affect reproductive success

Question 24

Gene flow

Answer 24

When individuals migrate between populations that have different allele frequencies. This enhances genetic diversity

Question 25

Allele

Answer 25

Variant form of a gene

Question 26

Bottleneck effect

Answer 26

Situation in which a population size is dramatically reduced and then rebounds. While population is small, genetic drift may rapidly reduce the genetic diversity in the population

Question 27

Deleterious allele

Answer 27

Being the “recessive allele”

Question 28

Founder effect

Answer 28

When a small group of individuals seperated from a larger population and establishes a colony in a new location

Question 29

Founder effect consequences

Answer 29

-founding population that is relatively small is expected to have less genetic variation than the larger original population that it came from

Question 30

Intersexual selection

Answer 30

• called mate choice
• members of one sex, usually female, choose their mates from individuals of the other Sex on the basis of certain desirable characteristics

Question 31

Intrasexual selection

Answer 31

Members of one Sex, usually makes, directly compete for the opportunity to mate with individuals of the opposite sex

Question 32

Micro evolution

Answer 32

• used to describe changes in a populations gene pool

- like changes in allele frequencies from generation to generation

Question 33

Natural selection

Answer 33

Process that eliminates those individuals that are less likely to survive and reproduce in a particular environment, while allowing other individuals with traits that confer greater reproductive success to increase in numbers

Question 34

Sexual selection

Answer 34

Where individuals with certain traits are more likely to engage in successful reproduction than other individuals

Question 35

Genetic drift and neutral variation

Answer 35

Changes in genes and proteins that do not have an effect on reproductive success

Question 36

Random mating

Answer 36

Members of a population choose their mates irrespective of their genotypes or phenotype

Question 37

Inbreeding

Answer 37

the mating of Two genetically related individuals such as cousins **

Question 38

Does inbreeding affect allele frequencies?

Answer 38

No, but it may have negative consequences with regard to recessive alleles

Question 39

Inbreeding depression

Answer 39

Produces homozygotes that are less fit, thereby decreasing the reproductive success of the population

Question 40

Inbreeding increases the chance of what?

Answer 40

Homozygous offspring are more likely to be produced

**rare recessive disease in humans are therefore more frequent