Biology HN- Evolution- Day 3

What are the four mechanisms of evolution?

Mutation, Natural Selection, Gene Flow (Migration), Genetic Drift

What is mutation in the context of evolution?

A change or damage to a gene that can affect traits in offspring.

How does natural selection operate?

Organisms best fit for their environment are more likely to survive, reproduce, and pass on their genes.

What is gene flow?

The movement of genes from one population to another, often through migration.

What is genetic drift?

The change of traits in a population due to random chance, with a larger effect on small populations.

What is the bottleneck effect?

A significant reduction in population size due to a disaster, leading to a loss of genetic diversity.

How did the bottleneck effect impact cheetahs?

Cheetahs experienced a bottleneck due to climate change, resulting in low genetic diversity and inbreeding.

What is the founder effect?

When a few members of a population start a new colony, leading to reduced genetic variation.

Provide an example of the founder effect.

The Afrikaner population in South Africa has a high frequency of Huntington's disease due to the original colonists carrying the gene.

What are the three modes of natural selection?

Directional, Stabilizing, and Disruptive (Diversifying) selection.

What is directional selection?

A mode of natural selection that favors one extreme phenotype over others, leading to a shift in trait distribution.

What is stabilizing selection?

A mode of natural selection that favors intermediate phenotypes and reduces variation.

What is disruptive selection?

A mode of natural selection that favors extreme phenotypes at both ends of the spectrum, leading to two or more contrasting phenotypes.

How does migration affect genetic variation?

Migration can increase genetic variation by introducing new alleles into a population.

What is the relationship between genetic drift and population size?

Genetic drift has a larger effect on small populations due to random chance events.

What happens to allele frequency during genetic drift?

Allele frequencies can change randomly, leading to increased or decreased prevalence of certain traits.

What is an example of a mutation that can be deleterious?

A mutation that turns off lactase production in adults, affecting their ability to digest lactose.

What is the significance of the 'race to survive' activity?

It illustrates the concept of natural selection and the survival of the fittest in a competitive environment.

What is the purpose of the M&M (fruit loop) lab?

To demonstrate genetic drift and the effects of random chance on allele frequencies in a population.

How do mutations contribute to evolution?

They introduce new genetic variations that can be acted upon by natural selection.

What is the impact of genetic drift on small populations?

It can lead to rapid changes in allele frequencies and potentially increase the risk of extinction.