Chapter23

Question 1

Microevolution

Answer 1

Evolution on its smallest scale, as change in allele frequencies in a population over a population over generations.

Question 2

Genetic Variation

Answer 2

Individuals in a population show differences in composition of their genes or other DNA segments.

Question 3

Average Heterozygosity

Answer 3

Average percentage of Loci (part of chromosome) that are Heterozygous

Question 4

Geographic Variation

Answer 4

Differences in the genetic composition of separate populations due to location

Question 5

Cline

Answer 5

Example of Geographic Variation, a graded change in a character along a geographic axis of gradiant

Question 6

4 Sources of Genetic Variation

Answer 6

Formation of New Alleles- Mutation
Altering Gene Number or Position- Chromosomal changes
Rapid Reproduction- faster rate of variation
Sexual Reproduction-Independent assortment, crossing over

Question 7

Gene Pool

Answer 7

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

Question 8

5 Conditions for Hardy- Weinberg Equilibrium

Answer 8

No Mutation- No change in the gene pool
Random Mating- Inbreeding Mixing of Gametes does not change
No Natural Selection-mate on a certain phenotypic trait
Extremely large population
No gene flow

Question 9

Genetic Drift

Answer 9

Chance Events can cause allele frequencies to fluctuate unpredictably from one to another esp. in small pop.

Question 10

Founder Effect

Answer 10

When few are separated and establish a new population whose gene pool differs from the source population .

Question 11

Bottleneck Effect

Answer 11

A severe drop in population size can cause a substantial effect on the gene pool of a population

Question 12

4 Effects of Genetic Drift

Answer 12

Significant in Small Populations
Allele Frequencies change at random
May lead to a loss of genetic variation in a population
May cause harmful alleles to be fixed.

Question 13

Gene Flow

Answer 13

The Transfer of allele into or out of a population due to the movement of fertile individuals or their gametes

Question 14

Relative Fitness

Answer 14

The contribution an individual makes to the gene pool of the next generation.

Question 15

Directional Selection

Answer 15

Conditions favor individuals exhibiting one of the extreme phenotypic range shifting the pop frequencies.

Question 16

Disruptive Selection

Answer 16

conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes

Question 17

Stabilizing Selection

Answer 17

Acts against both extreme phenotypes and favors an intermediate.

Question 18

Sexual Selection

Answer 18

Certain inherited characteristics are more likely than other individuals to obtain mates

Question 19

Sexual Dimorphism

Answer 19

Differences between phenotypes of the sexes.

Question 20

Intrasexual Selection

Answer 20

selection within the same sex they compete directly for mates

Question 21

Intersexual selection

Answer 21

When one mate chooses who to partner with.

Question 22

Neutral Variation

Answer 22

Differences in DNA sequence that do not confer a select advantage or disadvantage

Question 23

Balancing Selection

Answer 23

when natural selection maintains two or more forms in a population includes heterozygote advantage and frequency dependent selection

Question 24

Heterozygote Advantage

Answer 24

individuals who are heterozygous at a particular locus have greater fitness than do both kinds of homozygotes defined in genotype not phenotype

Question 25

Frequency Dependent Selection

Answer 25

fitness depends on how common one is in the population