Evolutionary Change in Populations

Question 1

Population gene pool

Answer 1

It includes all the alleles for all the loci present in the population.

Question 2

Genotype frequency

Answer 2

The proportion of a particular genotype in the population.

Question 3

Phenotype frequency

Answer 3

The proportion of a particular phenotype in the population.

Question 4

Allele frequency

Answer 4

The proportion of a specific allele of a given genetic locus in the population.

Question 5

Hardy-Weinberg principle

Answer 5

It states that allele and genotype frequencies do not change from generation to generation in a population at genetic equilibrium.
It requires random mating, no net mutations, large population, no migration, and no natural selection.
p (dominant allele) + q (recesive allele) = 1

Question 6

Genotype frequencies equation

Answer 6

p2 + 2pq + q2 = 1. p2 is the frecuency of the homozygous dominant, 2pq the frecuency of the heterozygous genotype, and q2 the frequency of the homozygous recessive gonotype.

Question 7

Microevolution

Answer 7

Is a change in allele or genotype frequencies within a population over successive generations.

Question 8

Nonrandom mating

Answer 8

It influences microevolution because individuals select mates on the basis of phenotype, indirectly selecting the corresponding genotype.

Question 9

Inbreeding

Answer 9

It influences microevolution because is the mating of genetically similar individuals that are more closely related than if they had been chosen at random from the population.
Inbreeding depression causes individuals to have lower fitness.

Question 10

Assortative mating

Answer 10

It influences microevolution because individuals select mates by their phenotypes.

Question 11

Mutations

Answer 11

It influences microevolution because undpredictable changes in DNA are the source of new alleles, increasing genetic variability.

Question 12

Genetic drift

Answer 12

It influences microevolution because is a random change in the allele frequencies of a small population, decreasing genetic variation.

Question 13

Gene flow

Answer 13

It influences microevolution because the movement of alleles caused by migration of individuals between populations causes changes in allele frequencies.

Question 14

Natural selection

Answer 14

It causes changes in allele frequencies that lead to adaptation.

Question 15

Stabilizing selection

Answer 15

It favors the mean at the expense of phenotypic extremes.

Question 16

Directional selection

Answer 16

It favors one phenotypic extreme over the other causing shift in the phenotypic mean.

Question 17

Disruptive selection

Answer 17

It favors two or more phenotypic extremes.

Question 18

Genetic polymorphism

Answer 18

It is the presence of genetic variation within a population.

Question 19

Balanced polymorphism

Answer 19

It is a special type of genetic polymorphism in which two or more alleles persist in a population over many generations as a result of natural selection.

Question 20

Heterozygote advantage

Answer 20

It occurs when the heterozygote exhibits greater fitness than either homozygote.

Question 21

Neutral variation

Answer 21

It is a genetic variation that confers no detectable selective advantage.

Question 22

Geographic variation

Answer 22

It is genetic variation that exists among different populations within the same species. A cline is a gradual change in a species’ phenotype and genotype frequencies through a series of geographically separate populations.