AP Biology Unit 7 practice questions: Natural Selection
8 original multiple-choice questions on AP Bio Unit 7, natural selection. Answer each one in your browser and read the explanation, then review the key ideas below.
Question 1 of 8
In a population in Hardy-Weinberg equilibrium, 16% of individuals show the recessive phenotype. What is the frequency of heterozygotes?
Question 2 of 8
Bacteria become resistant to an antibiotic over time because
Question 3 of 8
The human arm, bat wing and whale flipper have the same arrangement of bones. These are
Question 4 of 8
Genetic drift has the strongest effect on
Question 5 of 8
A new species forms from a population that lives in the same area as its parent species, for example through polyploidy in plants. This is
Question 6 of 8
On a phylogenetic tree, two species are most closely related if they
Question 7 of 8
Natural selection acts directly on an organism's
Question 8 of 8
A few birds blown to a new island start a population whose allele frequencies differ from the mainland's. This is
Key ideas in Unit 7
- Natural selection acts on phenotypes; individuals with heritable traits suited to their environment leave more offspring.
- Genetic drift (including founder and bottleneck effects) changes small populations by chance; gene flow mixes populations.
- Hardy-Weinberg: p² + 2pq + q² = 1 when there is no evolution, which gives a baseline to test against.
- Evidence for evolution includes homologous structures, fossils, DNA and protein comparisons, and biogeography.
- Speciation needs reproductive isolation: allopatric with a physical barrier, sympatric without one. Phylogenetic trees show common ancestry.
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