Mechanisms of Evolution

Question 1

5 Factors that lead to evolution

Answer 1

Mutations, Gene flow, genetic drift, non-random mating, natural selection

Question 2

Mutations

Answer 2

Randomly introduces new alleles into a population. Changes the DNA, a heritable mutation can affect an entire gene pool

Question 3

Geneflow

Answer 3

Migration - describes the net movement of alleles from one population to another as a result of the migration of individuals. Can change allele frequencies in either or both populations.

Question 4

Non - Random mating

Answer 4

Mating among individuals on the basis of mate selection for a particular phenotype or due to inbreeding. Increases homozygous individuals within a population.

Question 5

Preferred phenotype

Answer 5

Mating is based on physical or behavioral traits

Question 6

Inbreeding

Answer 6

When closely related individuals mate. Increases the frequency of homozygous, but makes the harmful recessive alleles more likely to be expressed (defects)

Question 7

Genetic drift

Answer 7

Random change in genetic variation due to chance

Question 8

Founder Effect

Answer 8

a change in a gene pool that occurs when a few individuals start a new isolated population. The founders of the new population will only contain a percentage of the original gene pool, so the diversity within the new gene pool in much lower.

Question 9

Bottleneck Effect

Answer 9

Will cause a change in gene distribution (natural disaster) within a population as a result of decrease in size. Since the surviving population is likely to only contain a fraction of the original gene pool, the diversity will be reduced.

Question 10

Natural Selection

Answer 10

Will alter the allele frequency of a population by skewing the frequency toward the most advantageous alleles.

Question 11

Sexual selection

Answer 11

The action of competing for a mate with the desirable alleles.

Question 12

Sexual Dimorphism

Answer 12

Same species but males and females will have different appearances

Question 13

Stabilizing selection

Answer 13

Favours intermediate (most common) phenotypes and acts against extreme variants

Question 14

Directional selection

Answer 14

Favours the phenotypes at one extreme over another resulting in the distribution curve of phenotypes shifting in the direction of that extreme. (environmental change)

Question 15

Disruptive selection

Answer 15

Favours the extremes of a range of phenotypes rather than intermediate phenotypes.