Week 21: Genetic Drift

Question 1

Genetic drift definition:

Answer 1

the changes in allele frequency in a population due to random variation in death and reproduction.

Question 2

Gene flow definition:

Answer 2

the process of alleles moving from one population to another

when individuals from one population migrate and interbreed with individuals of another population

Question 3

Population definition:

Answer 3

a group of individuals of the same species that have the potential to interact in the same space and time.

Question 4

Question page 4

Question 5

Evolutionary Processes 3 main mechanisms:

Answer 5

1. Natural selection
2. Genetic drift
3. Gene flow

Question 6

Natural selection:

Answer 6

Allele frequencies in a population change due to differences in survivorship and/or reproduction due differential success of different traits in a given environment.

Question 7

Is natural selection random or non-random?

Answer 7

non-random

Question 8

fitness =

Answer 8

“reproduction of the fittest” – producing the maximum # of healthy offspring.

Question 9

Differential traits – come from _______________

Answer 9

genetic variation

Question 10

Is Genetic drift random or non-random?

Answer 10

random

Question 11

question page 12

Question 12

genetic drift is a result of chance events such as

Answer 12

• Randomness associated with meiosis/ fertilization can change allele frequencies
• Random mortality (death) can change allele frequencies

Question 13

Question on page 19

Question 14

Founder Effect:

Answer 14

New population likely to have different allele frequencies than source population, by chance

when a small group of individuals establishes a new population in a new area

This effect is a type of genetic drift, a random process that can influence the genetic makeup of a population

Question 15

Genetic Bottleneck

Answer 15

Results when most individuals in a large population die

Small group of individuals left likely to have different allele frequencies than original population, by chance

Question 16

example of genetic bottleneck

Answer 16

Ex. Due to earthquakes, floods, fire, drought, human activity

Question 17

Does inbreeding depression cause extinction?

Answer 17

Small population → inbreeding → loss of genetic variability → reduction in individual fitness and population adaptability → higher mortality/ less reproduction → smaller population

Question 18

Black Footed Ferrets (BFF) and genetic bottle neck relationship

Answer 18

Once widely distributed and common, then considered extinct as of 1978.

Specialist predator of prairie dogs

Question 19

How do we counter the problems of genetic drift in small, threatened populations? In the case of BFF

Answer 19

1. Captive Breeding and Reintroduction Programs
2. Research on plague vaccines, breeding resistance

Question 20

Threats to BFF’s

Answer 20

Suitable sites and availability of prairie dogs as prey.

Sylvatic plague