9C Genetic drift and gene flow

Match the following definitions with the correct term.

• Founder effect

• A large proportion of a population is wiped out by a random event, significantly impacting allele frequencies.

• Bottleneck effect

• Allele frequencies changing drastically due to random events.

• Genetic drift

• A small unrepresentative sample of individuals separates from a larger population, usually lowering the genetic diversity.

• Gene flow

• The movement of alleles between different populations.

What effect is genetic drift likely to have on a population?

• Increased genetic diversity

• Unchanged genetic diversity

• Decreased genetic diversity

Why is lower genetic diversity a bad thing for a population?

• It makes it hard to tell the difference between individuals.

• It results in lower adaptive potential.

• It makes the population more likely to survive the emergence of a new disease.

• It reduces the chance of inbreeding.

Which of these is not a cause of gene flow between populations?

• Mutations

• Immigration

• Emigration

• Interbreeding

What type of population are genetic drift and gene flow more likely to significantly affect?

• A large population

• A small population

• Neither, it affects large and small populations in the same way

Sort these mechanisms into categories based on their effect on genetic diversity.

Groups:

(a) Decreases genetic diversity

,

(b) Increases genetic diversity

• Emigration

• Immigration

• Founder effect

• Interbreeding

• Bottleneck effect

A forest fire ignites in the Sam Houston State Forest and kills many members of a population of pigmy rattlesnakes. This is an example of:

• Gene flow

• Founder effect

• Bottleneck effect

• Inbreeding

What mechanism is shown in this image?

• Gene flow

• Bottleneck effect

• Founder effect

• Inbreeding

Maria Concepcion Soto settled in the northern area of Venezuela. She suffered from a rare genetic disorder called Huntington’s Disease. As a result, the now 20,000 individuals who live there also have a high risk of Huntington’s Disease. This is an example of:

• Gene flow

• Bottleneck effect

• Founder effect

• Inbreeding

Pollen from a population of flowers on one side of a river travels by wind to a population of flowers on the other side of the river. This is an example of:

• Gene flow

• Bottleneck effect

• Founder effect

• Inbreeding