Evolution Study Guide: Mechanisms and Evidence

What are the 5 mechanisms for evolution?

Natural selection, genetic drift, mutation, gene flow, and non-random mating.

Which mechanism can result in evolution?

Natural selection.

Which mechanism can result in adaptations?

Natural selection.

What provides variation for evolution to act upon?

Mutations.

When is speciation likely to take place?

When genetic variation is low.

What changes as the environment changes?

The traits of a population.

What can be good, bad, or make no difference?

Mutations.

What are the 4 main pieces of evidence for evolution?

Fossil records, comparative anatomy, comparative embryology, and molecular biology.

What does natural selection act upon?

Variations in traits that affect survival and reproduction.

What are the principles of natural selection?

Variation, competition, survival of the fittest, and reproduction.

What causes variations in a population?

Mutations, gene flow, and sexual reproduction.

What is genetic drift?

A random change in allele frequencies in a population.

How does genetic drift differ from natural selection?

Genetic drift is random, while natural selection is a non-random process that favors traits that improve survival.

What is the Bottleneck Effect?

A sharp reduction in the size of a population due to environmental events, leading to reduced genetic diversity.

What is an example of the Bottleneck Effect?

The Northern elephant seal, which was hunted to near extinction.

What is the Founders Effect?

When a small group from a population starts a new population, leading to reduced genetic variation.

What is an example of the Founders Effect?

The Amish population in the U.S. showing higher frequencies of certain genetic disorders.

What is speciation?

The process by which new species arise.

What makes species unique?

Reproductive isolation and genetic differences.

What factors contribute to evolving a new species?

Geographic isolation, genetic divergence, and reproductive isolation.

What are the five assumptions of Hardy-Weinberg equilibrium?

Large population size, no mutations, no gene flow, random mating, and no natural selection.

What does the Hardy-Weinberg formula represent?

p^2 + 2pq + q^2 = 1, where p is the frequency of the dominant allele and q is the frequency of the recessive allele.

What is natural selection all about in two words?

Survival and reproduction.

What is the importance of variation in a population?

It allows for adaptation to changing environments.

What affects whether a new trait will become common in a population?

The trait's impact on survival and reproduction.

What could cause a new coat color in a mouse population to become more frequent?

If the brown coat color provides better camouflage, leading to higher survival rates.

Why is the crab's adaptation of attaching items beneficial?

It enhances camouflage, improving survival against predators.

What happens to the population of crickets with silent wings over time?

The silent-winged crickets may increase in frequency if they avoid predation.

What likely caused the increase in shell thickness in blue mussels?

Increased predation pressure from the Asian shore crab.