Chapter 20.5 - Nonadaptive Mechanisms of Evolution

Question 1

Textbook:
What are the 5 evolutionary mechanisms?

Answer 1

1. Natural Selection
2. Non-random Mating
3. Mutation
4. Genetic drift
5. Gene flow/Migration

Question 2

Textbook:
What is genetic drift?

Answer 2

Random change in allele frequencies from generation to generation

Question 3

Textbook:
What population does genetic drift mainly affect?

Answer 3

Genetic drifts has a larger affect on smaller population

Question 4

Textbook:
What is population bottleneck?

Answer 4

An extreme reduction in population size that may result in marked loss of genetic diversity and possibly genetic drift. It is temporary

Question 5

Textbook:
What is a founder’s effect? Give an example.

Answer 5

• When a few individuals start a new population. This also causes genetic drift
• When a small number of individuals arrive on an island and colonize it

Question 6

Textbook:
What will happen if genetic drift occurs in a large population?

Answer 6

Changes in allele frequency from generation to generation is much smaller. Typically less than 1%

Question 7

What decreases and increases genetic variation?

Answer 7

Migration decreases genetic variation, and mutation increases genetic variation

Question 8

What is migration?

Answer 8

The movement in individuals from one population to another, resulting in gene flow

Question 9

What is gene flow?

Answer 9

The movement of alleles from one population to another

Question 10

What is the consequence of migration?

Answer 10

The consequence of migration is the homogenization of populations, meaning making them similar to each other and reducing genetic differences between them.

Question 11

What alters genotype frequencies without affecting the allele frequencies?

Answer 11

Nonrandom mating

Question 12

What is random mating?

Answer 12

When species select mates without regard to genotype.

Question 13

What is nonrandom mating?

Answer 13

When species select mates according to their genotype.

Question 14

What does nonrandom mating do?

Answer 14

Redistributes alleles that’s already in the gene pool (does not add new alleles to the population).

Question 15

What is inbreeding? What does it lead to?

Answer 15

• Mating between close relatives.
• Leads to loss of heterozygotes frequency and increase of homozygotes frequency without affecting allele frequencies.

Question 16

What is inbreeding depression?

Answer 16

A reduction in fitness resulting from inbreeding causing homozygosity of harmful (deleterious) recessive mutations.

Question 17

What almost caused the extinction of the Florida panther population?

Answer 17

Inbreeding