AP Exam Prep · AP Biology
AP Biology Unit 7 Practice Test: Natural Selection
Unit 7 carries the largest exam weighting. It explains how populations change over time, how to measure that change with Hardy–Weinberg, what evidence supports common ancestry, and how new species form.
- Exam weighting:
- 13–20%
- Questions:
- 13 multiple choice
- Time:
- about 17 minutes
- Cost:
- Free, no sign-up
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What AP Bio Unit 7 covers
Unit 7, Natural Selection, makes up 13–20% of the multiple-choice section and usually takes ~19–21 class periods. These are the topics in the current course framework, and every question in the test above is tagged with one of them.
- 7.1Introduction to Natural Selection
- 7.2Natural Selection
- 7.3Artificial Selection
- 7.4Population Genetics
- 7.5Hardy–Weinberg Equilibrium
- 7.6Evidence of Evolution
- 7.7Common Ancestry
- 7.8Continuing Evolution
- 7.9Phylogeny
- 7.10Speciation
- 7.11Variations in Populations
- 7.12Origins of Life on Earth
Unit 7 key ideas
Selection acts on variation
Individuals with heritable traits that suit the environment survive and reproduce more, so those alleles become more common. Populations evolve; individuals do not.
Other forces change allele frequencies
Genetic drift (strongest in small populations), gene flow, mutation and nonrandom mating also change a population's genetics.
Hardy–Weinberg is a null model
p + q = 1 and p² + 2pq + q² = 1 describe a population that is not evolving. Differences from these predictions show that evolution is happening.
Evidence and relationships
Fossils, homologous structures, shared DNA sequences and the universal genetic code support common ancestry. Phylogenetic trees show hypotheses about relatedness.
Common Unit 7 mistakes
- Saying organisms change because they need to (an individual can't evolve a trait on purpose).
- Using 2pq when the question asks for q², or forgetting to take the square root.
- Treating analogous structures as evidence of close relationship.
How to study this unit
- In Hardy–Weinberg problems, start from the recessive phenotype frequency, which equals q².
- On phylogenetic trees, read relatedness from the most recent common ancestor, not from how close the tips are.
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About these questions
StudyCoach wrote these questions for this test. Each one is mapped to a topic in the College Board's current AP Biology course framework. Every answer key was also checked by a separate AI review, and any disagreement was rechecked by hand. They have not yet been reviewed by an AP Biology teacher. If you think an answer is wrong, email support@studycoach.io.
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