Genetic drift

Question 1

What is genetic drift?

Answer 1

Is a mechanism of evolution in which allele frequencies of a population change over generations due to chance. There is a loss of genetic variation over generations.

Question 2

What is a gene pool?

Answer 2

A gene pool is the sum of the alleles ina given population. Gene pools and allele frequencies are studied to observe how characteristics in a population are changing overtime.

Question 3

What is a genetic mutation?

Answer 3

Is a permanent change in the DNA sequence of a gene. It introduces new alleles into populations and is the ultimate source of variation.

Question 4

What happens if alleles from the gene pool are lost?

Answer 4

Biodiversity decreases.

Question 5

What are 5 ways allele frequencies change?

Answer 5

1. Mutations
2. Migration
3. Natural Selection
4. Non random mating
5. Genetic drifting

Question 6

What are the 3 forms/ways genetic drift occurs?

Answer 6

1. Random genetic drift
2. Founder effect
3. Bottleneck effect

Question 7

What is random genetic drift?

Answer 7

• Is a mechanism of evolution in which allele frequencies of a population change over generations due to chance events, not selection.
• Occurs in all populations but affects small populations more often.
• Results in the loss of some beneficial alleles and the fixation of other alleles.

Question 8

What is the founder’s effect?

Answer 8

• A small group of individuals splits off to start a new population.
• Has a stronger effect on smaller populations.
• The alleles in the founder population may not be representative of the original population.
• When the population increases the gene pool only represents the founder population not the original.

Question 9

What is the bottleneck effect?

Answer 9

• Is a sudden reduction in population size.
• Surviving individuals constitute a random sample of the original population.
• Population numbers may recover but the gene pool will remain the same.
• Populations with a small gene pool are more susceptible to environmental changes and therefore have an increased risk of extinction.

Question 10

What are 4 examples of environmental changes that can cause a decrease in population?

Answer 10

1. Drought
2. Flood
3. Fire
4. Hunting

Question 11

How does genetic drift change allele frequencies in the gene pool of a population?

Answer 11

• Is a mechanism of evolution in which allele frequencies of a population change over generations due to chance. There is a loss of genetic variation over generations.
• Results in the loss of beneficial alleles and the fixation of some alleles
• Happens because of the small population size and the bottleneck and founder effect.