Study Guide: Evolutionary Mechanisms and Population Genetics

Q1. Describe the difference between microevolution and macroevolution.

Background

Topic: Evolutionary Biology

This question tests your understanding of the scales at which evolutionary changes occur and how they are defined in biology.

Key Terms:

• Microevolution: Small-scale changes in allele frequencies within a population over time.

• Macroevolution: Large-scale evolutionary changes that result in the formation of new species or groups above the species level.

Step-by-Step Guidance

1. Start by defining microevolution and macroevolution in your own words, focusing on the scale and outcomes of each process.

2. Think about examples: Microevolution might involve changes in coloration in a population, while macroevolution could involve the emergence of entirely new species.

3. Consider the time scale and genetic changes involved in each process.

4. Reflect on how microevolutionary processes can accumulate to result in macroevolutionary changes over long periods.

Try explaining the difference in your own words before checking the answer!

Q2. What is evolution? What mechanisms can cause the evolution of populations?

Background

Topic: Evolutionary Mechanisms

This question is testing your understanding of the definition of evolution and the processes that drive changes in populations over time.

Key Terms:

• Evolution: A change in the genetic composition of a population from generation to generation.

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

Step-by-Step Guidance

1. Begin by writing a concise definition of evolution as it applies to populations.

2. List the main mechanisms that can cause evolution in populations.

3. Briefly describe how each mechanism can change allele frequencies in a population.

4. Think about examples of each mechanism in nature.

Try listing and describing the mechanisms before revealing the answer!

Q3. ___________ acts on individuals but only ___________ evolve.

Background

Topic: Natural Selection and Evolution

This fill-in-the-blank question tests your understanding of the distinction between the level at which selection operates and the level at which evolution occurs.

Key Concepts:

• Natural selection acts on individuals.

• Populations evolve.

Step-by-Step Guidance

1. Recall what natural selection is and at what biological level it operates.

2. Think about what it means for a group to evolve versus an individual.

3. Fill in the blanks with the appropriate terms based on your understanding.

Try filling in the blanks before checking the answer!

Q4. Explain how genetic variation makes evolution possible.

Background

Topic: Genetic Variation and Evolution

This question is testing your understanding of why genetic diversity is essential for evolutionary processes.

Key Terms:

• Genetic Variation: Differences in DNA sequences among individuals in a population.

• Evolution: Change in allele frequencies over time.

Step-by-Step Guidance

1. Define genetic variation and explain its sources.

2. Describe why populations without genetic variation cannot evolve.

3. Connect the presence of genetic variation to the ability of populations to adapt to changing environments.

4. Think of examples where lack of variation has limited evolutionary potential.

Try explaining the importance of genetic variation before revealing the answer!

Q5. Identify sources of genetic variation.

Background

Topic: Sources of Genetic Diversity

This question is testing your knowledge of how new genetic differences arise in populations.

Key Terms:

• Mutation: Changes in DNA sequence.

• Sexual Reproduction: Recombination of alleles during meiosis and fertilization.

• Gene Flow: Movement of alleles between populations.

Step-by-Step Guidance

1. List the main sources of genetic variation in populations.

2. Briefly describe how each source contributes to genetic diversity.

3. Consider examples of each source in nature.

Try listing the sources before checking the answer!

Q6. Define population and gene pool.

Background

Topic: Population Genetics

This question is testing your understanding of basic terms used in population genetics.

Key Terms:

• Population: A group of individuals of the same species living in the same area and interbreeding.

• Gene Pool: The total collection of genes and their alleles in a population at any one time.

Step-by-Step Guidance

1. Write a clear definition for 'population' in the context of biology.

2. Define 'gene pool' and explain its significance in evolution.

3. Think about how changes in the gene pool reflect evolutionary processes.

Try defining these terms before revealing the answer!

Q7. What is Hardy-Weinberg equilibrium? What are the five conditions? (Be able to answer calculation problems. Pay attention if the question asks for an allelic or genotypic frequency.)

Background

Topic: Population Genetics and Hardy-Weinberg Principle

This question is testing your understanding of the Hardy-Weinberg equilibrium, its assumptions, and how to use its equations to calculate allele and genotype frequencies.

Key Formulas:

• $p + q = 1$ (where $p$ and $q$ are the frequencies of two alleles)

• $p^2 + 2pq + q^2 = 1$ (where $p^2$, $2pq$, and $q^2$ are the frequencies of the three possible genotypes)

Five Conditions for Hardy-Weinberg Equilibrium:

• No mutations

• Random mating

• No natural selection

• Extremely large population size

• No gene flow

Step-by-Step Guidance

1. Define Hardy-Weinberg equilibrium and explain what it means for a population to be in equilibrium.

2. List the five conditions required for a population to remain in Hardy-Weinberg equilibrium.

3. Review the formulas for calculating allele and genotype frequencies.

4. Practice setting up a sample calculation (e.g., if given $p$, find $q$, or vice versa).

5. Be sure to distinguish between allele frequency ($p$, $q$) and genotype frequency ($p^2$, $2pq$, $q^2$).

Try setting up a sample calculation before checking the answer!

Q8. Describe how natural selection, genetic drift, and gene flow affect allele frequencies and thus, result in evolutionary change. (If given an example, be able to identify which one is occurring. What were the four effects of genetic drift mentioned during lecture?)

Background

Topic: Mechanisms of Evolution

This question is testing your understanding of how different evolutionary mechanisms change allele frequencies in populations and the specific effects of genetic drift.

Key Terms:

• Natural Selection: Differential survival and reproduction of individuals due to differences in phenotype.

• Genetic Drift: Random changes in allele frequencies, especially in small populations.

• Gene Flow: Movement of alleles between populations.

Four Effects of Genetic Drift:

• Significant in small populations

• Can cause allele frequencies to change at random

• Can lead to loss of genetic variation

• Can cause harmful alleles to become fixed

Step-by-Step Guidance

1. Describe how each mechanism (natural selection, genetic drift, gene flow) changes allele frequencies.

2. Give an example of each mechanism in action.

3. List and explain the four effects of genetic drift.

4. Practice identifying which mechanism is at work in a given scenario.

Try explaining each mechanism and its effects before revealing the answer!

Q9. Is natural selection random? What does natural selection cause?

Background

Topic: Natural Selection

This question is testing your understanding of the nature of natural selection and its outcomes.

Key Concepts:

• Natural selection is not a random process.

• It leads to adaptation of populations to their environment.

Step-by-Step Guidance

1. Consider whether the process of natural selection is random or non-random, and why.

2. Explain what natural selection results in, especially in terms of adaptation and fitness.

3. Think of examples where natural selection has led to specific adaptations.

Try answering these questions before checking the answer!

Q10. Define adaptive radiation.

Background

Topic: Macroevolution and Speciation

This question is testing your understanding of how new species can rapidly diversify from a common ancestor.

Key Terms:

• Adaptive Radiation: The rapid evolution of diversely adapted species from a common ancestor when new environmental opportunities arise.

Step-by-Step Guidance

1. Write a concise definition of adaptive radiation.

2. Think of classic examples (e.g., Darwin's finches).

3. Explain the conditions that can lead to adaptive radiation.

Try defining adaptive radiation before revealing the answer!

Q11. What is sexual selection? What can sexual selection result in?

Background

Topic: Mechanisms of Evolution

This question is testing your understanding of sexual selection and its evolutionary consequences.

Key Terms:

• Sexual Selection: A form of natural selection where individuals with certain inherited traits are more likely to obtain mates.

• Sexual Dimorphism: Differences in appearance between males and females of a species due to sexual selection.

Step-by-Step Guidance

1. Define sexual selection and explain how it differs from natural selection.

2. Describe the types of traits that can evolve due to sexual selection.

3. Explain what sexual dimorphism is and how it relates to sexual selection.

4. Think of examples in nature (e.g., peacock tails, antlers in deer).

Try explaining sexual selection and its outcomes before revealing the answer!