Chapter 23

Question 1

Acts on individuals but only populations evolve

Answer 1

Natural Selection

Question 2

Is a change in allele frequencies in a population over generations

Answer 2

Microevolution

Question 3

The three main mechanism that cause an allele frequency change.

Answer 3

Natural selection, genetic drift and gene flow

Question 4

Among individuals is caused by differences in genes or other DNA segments

Describes how allele frequencies fluctuate unpredictable from one generation to the next

Answer 4

Genetic drift

Question 5

Is the product of inherited genotype and environmental influences

Answer 5

Phenotype

Question 6

Measures the average percent of loci that are heterozygous in a population

Answer 6

Heterozygosity

Question 7

Quantifying the whole gene-level as the average percentage of loci that are heterozygous

Answer 7

Gene viability

Question 8

Is measured by comparing the DNA sequences of 2 or more individuals

Answer 8

Nucleotide Viability

Question 9

What are the only mutated cells that can be passed to the offspring

Answer 9

Cells that produce Gametes

Question 10

Which types of chromosomal mutations, involving multiple gene locations, commonly result in harmful effects?

Answer 10

Delete, Disrupt or Rearrange

Question 11

Is required for a population to evolve, but does not guarantee that it will.

Answer 11

Genetic Variation

Question 12

Describes the genetic make-up we expect for a population that is not evolving at a particular locust

Answer 12

Hardy-Weinburg Equation

Question 13

Is a localized group of individuals capable of interbreeding and producing fertile offspring

Answer 13

Population

Question 14

Consist of all the alleles of all loci in a population

Answer 14

Gene pool

Question 15

The three major factors that alter allele frequencies and bring about evolutionary change

Answer 15

Natural selection, gene flow, genetic drift

Question 16

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

Answer 16

Adaptive evolution

Question 17

Occurs when a few individuals become isolated from a larger population

Answer 17

Founder effect

Question 18

Occurs when there is a drastic reduction in population size due to a sudden change in environment

Answer 18

Bottleneck effect

Question 19

Significant in small populations
can cause allele frequencies to change at random
can lead to a loss of genetic variation within populations
can caused harmful alleles to become fixed

Answer 19

these are the effects of Genetic Drift

Question 20

Consists of the movement of alleles among populations

Answer 20

Gene flow

Question 21

Can be transferred through the movement of fertile individuals or gametes

Answer 21

Alleles

Question 22

Evolution by natural selection involves both?

Answer 22

Chance and sorting

Genetic variation arise by chance
Beneficial Alleles are “sorted” and favored by natural selection

Question 23

Favors individuals at one extreme end of the phenotypic range

Answer 23

Directional Selection

Question 24

Favors individuals at both extremes of the phenotypic range

Answer 24

Disruptive Selection

Question 25

Favors intermediate variants and acts against extreme phenotypes

Answer 25

Stabilizing Selection

Question 26

Is a process in which individuals with certain inherited characteristics are more likely to acquire mates than other individuals of the same sex

Answer 26

Sexual Selection

Question 27

Marked differences between the sexes in secondary sexual characteristics

Answer 27

Sexual Dimorphism

Question 28

Is direct competition among individuals of one sex (often males) for mates of the opposite sex

Answer 28

Intrasexual selection

Question 29

Often called mate choice, occurs when individuals of one sex (usually females) are choosy in selecting their mates

Answer 29

Intersexual Selection

Question 30

Occurs when natural selection maintains stable frequencies of two or more phenotypic forms in a population

Answer 30

Balancing Selection

Question 31

Balancing Selection Includes?

Answer 31

Frequency-Dependent selection Heterozygote advantage

Question 32

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

Answer 32

Frequency-dependent Selection

Question 33

Occurs when heterozygotes have a higher fitness than both homozygotes Can result from stabilizing or directional selection

Answer 33

Heterozygote Advantage

Question 34

Maintains genetic variation in the form of recessive alleles hidden from selection in heterozygotes

Answer 34

Diploidy