Topic 1 Evolution: Causes of Changes in Allele Frequencies

Question 1

• The increase and decrease of allele frequencies due to adaptations to the environment.

Answer 1

Natural Selection

Question 2

• The introduction and removal of alleles from the population when individuals leave (emigration) or enter the population

Answer 2

Gene Flow

Question 3

• The random increase and decrease of an allele by chance. Genetic drift has a larger effect on small populations.

Answer 3

Genetic Drift

Question 4

• When a small group of individuals migrate to a new location, the gene pool of the small group will be less than the original population. After successive generations, the genetic makeup will be unique from the original population.

Answer 4

1. Founder Effect

Question 5

• Occurs when the population undergoes a dramatic decrease in size due to natural catastrophes or other events. The population is now vulnerable to genetic drift, and the gene pool is much smaller

Answer 5

2. Bottleneck Effect

Question 6

• Individuals choose mates based upon their particular traits

Answer 6

Nonrandom Mating

Question 7

1. Inbreeding

2. Sexual Selection

Answer 7

Types of Nonrandom Mating

Question 8

• Individuals mate with relatives. This changes genotype proportions but not allele frequency

Answer 8

1. Inbreeding

Question 9

• Females choose males based on superior traits

Answer 9

2. Sexual Selection

Question 10

• New alleles can be introduced through mutations, and these mutations happen randomly.

Answer 10

Mutations