Ap Bio Evolution Practice Test

Ace Your AP Bio Evolution Exam: A Comprehensive Practice Test and Review

Understanding evolution is crucial for success in the AP Biology exam. This comprehensive guide provides a robust practice test focusing on evolutionary concepts, followed by detailed explanations, addressing common misconceptions and reinforcing key principles. Mastering these concepts will significantly boost your confidence and prepare you for exam day. We'll cover topics ranging from natural selection and genetic drift to speciation and phylogenetic analysis. Let's dive in!

Section 1: Multiple Choice Questions

Instructions: Choose the best answer for each multiple-choice question.

1. Which of the following is NOT a condition required for Hardy-Weinberg equilibrium? a) Large population size b) Random mating c) No gene flow d) Natural selection e) No mutations

2. What type of selection favors individuals with extreme phenotypes? a) Stabilizing selection b) Directional selection c) Disruptive selection d) Balancing selection e) Sexual selection

3. The process by which new species arise is called: a) Adaptation b) Speciation c) Natural selection d) Genetic drift e) Evolution

4. Homologous structures, such as the forelimbs of vertebrates, provide evidence for: a) Convergent evolution b) Divergent evolution c) Parallel evolution d) Coevolution e) Adaptive radiation

5. Which of the following is an example of a prezygotic reproductive isolating mechanism? a) Hybrid sterility b) Hybrid breakdown c) Habitat isolation d) Reduced hybrid viability e) Gametic isolation

6. The gradual change in allele frequencies across a geographic range is known as: a) Genetic drift b) Bottleneck effect c) Founder effect d) Clinal variation e) Gene flow

7. Phylogenetic trees are diagrams that represent: a) The fossil record b) Evolutionary relationships c) The geographic distribution of species d) The genetic diversity within a population e) The rate of speciation

8. Which type of selection favors the intermediate phenotype? a) Directional selection b) Disruptive selection c) Stabilizing selection d) Balancing selection e) Sexual selection

9. The accumulation of small, incremental changes over long periods leads to: a) Punctuated equilibrium b) Gradualism c) Adaptive radiation d) Convergent evolution e) Allopatric speciation

10. What mechanism explains the evolution of antibiotic resistance in bacteria? a) Artificial selection b) Natural selection c) Sexual selection d) Genetic drift e) Founder effect

Section 2: Free Response Questions

Instructions: Answer the following free-response questions in complete sentences.

1. Explain the five conditions that must be met for a population to be in Hardy-Weinberg equilibrium. Describe how the violation of each condition can lead to evolutionary change.

2. Compare and contrast allopatric and sympatric speciation. Provide examples of each type of speciation. Discuss the role of reproductive isolating mechanisms in each process.

3. Describe three different types of natural selection (directional, stabilizing, disruptive). For each type, explain how it affects the distribution of phenotypes in a population and provide a real-world example.

4. Explain the concept of phylogenetic trees and how they are used to illustrate evolutionary relationships. Discuss the different types of phylogenetic trees and the information they can convey about evolutionary history. Explain how homologous and analogous structures are used in constructing phylogenetic trees.

Section 3: Answer Key and Explanations

Multiple Choice Answers:

1. d) Natural selection
2. c) Disruptive selection
3. b) Speciation
4. b) Divergent evolution
5. c) Habitat isolation
6. d) Clinal variation
7. b) Evolutionary relationships
8. c) Stabilizing selection
9. b) Gradualism
10. b) Natural selection

Multiple Choice Explanations:

1. Hardy-Weinberg equilibrium describes a population that is not evolving. Natural selection directly leads to changes in allele frequencies.

2. Disruptive selection favors individuals at both phenotypic extremes, leading to a bimodal distribution.

3. Speciation is the process of forming new and distinct species.

4. Homologous structures share a common ancestry, indicating divergent evolution.

5. Prezygotic mechanisms prevent mating or fertilization. Habitat isolation prevents species from encountering each other.

6. Clinal variation refers to a gradual change in a trait along a geographic gradient.

7. Phylogenetic trees depict evolutionary relationships among organisms.

8. Stabilizing selection favors the intermediate phenotype, reducing variation.

9. Gradualism proposes that evolution occurs through the accumulation of small changes over time.

10. Antibiotic resistance evolves through natural selection, where resistant bacteria survive and reproduce.

Free Response Explanations:

1. Hardy-Weinberg Equilibrium Conditions:

   • Large population size: Prevents genetic drift, which is the random fluctuation of allele frequencies in small populations. Violation leads to allele frequency changes due to chance events.
   • Random mating: Prevents non-random mating patterns (e.g., assortative mating) from altering allele frequencies. Violation leads to changes in genotype frequencies.
   • No gene flow: Prevents the migration of alleles into or out of the population. Violation leads to changes in allele frequencies as alleles are introduced or lost.
   • No mutations: Prevents the introduction of new alleles into the population. Violation leads to the creation of new alleles and altered allele frequencies.
   • No natural selection: Prevents differential survival and reproduction based on phenotype. Violation leads to changes in allele frequencies as advantageous alleles increase in frequency.

2. Allopatric vs. Sympatric Speciation:

   • Allopatric speciation: Occurs when populations are geographically separated, preventing gene flow. Over time, genetic divergence leads to reproductive isolation. Example: Darwin's finches on the Galapagos Islands. Reproductive isolating mechanisms evolve during geographic isolation.

   • Sympatric speciation: Occurs within the same geographic area, often due to factors like polyploidy (in plants), sexual selection, or habitat differentiation. Example: Apple maggot flies specializing on different host plants. Reproductive isolating mechanisms evolve within the same geographic range. Both processes result in the formation of new species, but differ in their geographic context.

3. Types of Natural Selection:

   • Directional selection: Favors one extreme phenotype over others. Example: Peppered moths during the Industrial Revolution. The distribution shifts towards the favored extreme.

   • Stabilizing selection: Favors the intermediate phenotype, reducing variation. Example: Human birth weight; very low or high birth weights are associated with higher mortality. The distribution becomes narrower around the mean.

   • Disruptive selection: Favors both extreme phenotypes, leading to bimodal distribution. Example: Darwin's finches with different beak sizes for different food sources. The distribution shows two peaks representing the favored extremes.

4. Phylogenetic Trees:

   Phylogenetic trees are branching diagrams that represent the evolutionary relationships among organisms. They illustrate the evolutionary history of a group of organisms, showing how species are related to each other through common ancestors. Different types of phylogenetic trees exist (cladograms, dendrograms, phylograms) that vary in the type of data they represent (relationships vs. evolutionary time). Homologous structures (shared ancestry) are used to infer evolutionary relationships, while analogous structures (similar function, different ancestry) can mislead phylogenetic analyses. Careful consideration of both morphology and molecular data (DNA, RNA) leads to more accurate and reliable phylogenetic trees.

This comprehensive practice test and review covers key evolutionary concepts crucial for success on the AP Biology exam. Remember to review your class notes, textbook, and other learning materials alongside this guide to ensure a thorough understanding of the subject matter. Good luck with your exam preparation!