Natural Selection and Genetic Drift

The video tutorial covers population genetics, focusing on mutation, genetic drift, gene flow, and natural selection. It explains how mutations alter DNA and phenotypes, and how genetic drift, including bottleneck and founder effects, impacts allele frequencies. Gene flow is discussed in terms of immigration and emigration, affecting genetic variation. The video also explores natural selection, detailing directional, stabilizing, and disruptive selection with examples like peppered moths and rock pocket mice.

What is a mutation in the context of population genetics?

• A change in the food supply

• A change in the population size

• A change in the DNA

• A change in the environment

How does genetic drift affect a population?

• It causes random changes in allele frequencies

• It stabilizes the population

• It increases the population size

• It ensures all alleles are passed on

What is the bottleneck effect?

• A type of natural selection

• An increase in genetic variation

• A drastic reduction in population size due to random events

• A situation where a small group starts a new population

In the founder effect, what happens to a population?

• It undergoes stabilizing selection

• It becomes more genetically diverse

• A small group becomes isolated and forms a new population

• It experiences a sudden increase in size

What is gene flow?

• The random loss of alleles

• The movement of alleles into or out of a population

• The stabilization of allele frequencies

• The increase of genetic drift

How does increased gene flow affect genetic variation between populations?

• It decreases variation between populations

• It increases variation between populations

• It causes populations to become extinct

• It has no effect on variation

What is directional selection?

• Selection that has no effect on phenotypes

• Selection that favors both extreme phenotypes

• Selection that favors one extreme phenotype

• Selection that favors the intermediate phenotype

Which type of selection reinforces the intermediate phenotype?

• Directional selection

• Stabilizing selection

• Random selection

• Disruptive selection

What is an example of disruptive selection?

• Gene flow between two populations

• Bottleneck effect in a population

• Rock pocket mice in different environments

• Peppered moths during the Industrial Revolution

In the context of natural selection, what happens during disruptive selection?

• The intermediate phenotype is favored

• Both extreme phenotypes are favored

• One extreme phenotype is favored

• No phenotypes are favored