AP Biology: Island Biogeography and Dispersal Practice Questions
Practice island biogeography and dispersal with original AP Biology multiple-choice questions. These items focus on colonization, extinction, distance effects, island size effects, and how species richness changes over time.
Free original practice questions for study purposes. Open Exam Prep is an independent study resource and is not affiliated with, endorsed by, or sponsored by the makers of AP Exams.
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1. According to island biogeography theory, which island is predicted to have the highest immigration rate for new species?
Explanation. Nearby islands usually receive more immigrants because dispersing organisms are more likely to reach them from the mainland or other source populations.
2. A large island and a small island are the same distance from the mainland. Which prediction is most consistent with island biogeography theory?
Explanation. Large islands often contain more habitats and larger populations. Larger populations are less likely to disappear by chance, so extinction rates are often lower.
3. A volcanic island forms near a continent. At first it has no terrestrial species. Which process is required before the island can develop a community of land plants and animals?
Explanation. New islands are colonized when organisms, seeds, spores, or other propagules disperse from existing populations and establish there.
4. Why does the immigration rate in the equilibrium model often decline as the number of species already on an island increases?
Explanation. As more source-pool species are already present, fewer absent species remain that can count as new immigrants, so the rate of new additions declines.
5. Why does the extinction rate in the equilibrium model often increase as species richness on an island increases?
Explanation. When more species live on the island, there are more populations that could go extinct, and limited resources can also increase competition.
6. In the classic island biogeography model, species richness is at equilibrium when which condition is met?
Explanation. Equilibrium richness is the point where new species are added by immigration at the same rate that resident species are lost by extinction.
7. A remote island and a near island are the same size. Which pattern would most strongly support an effect of distance on colonization?
Explanation. Distance affects immigration because closer islands are easier for organisms or propagules to reach from source populations.
8. A bird species reaches an island by flying, while a small mammal species rarely reaches the same island. What is the best explanation?
Explanation. Traits such as flight, floating seeds, dormancy, and tolerance of salt water can make some species much better dispersers than others.
9. A hurricane carries floating vegetation with insects to an island. Some insects survive and reproduce. Which term best describes the movement that allowed colonization?
Explanation. Passive dispersal occurs when organisms are transported by wind, water, or rafting rather than moving under their own power for the entire trip.
10. Which observation would best show species turnover on an island even if total species richness stays about the same?
Explanation. Turnover means the identities of species change through immigration and extinction, even when the total number of species remains near equilibrium.
11. A conservation biologist wants to design a habitat reserve that reduces local extinction risk. Which design best follows island biogeography principles?
Explanation. Larger habitat patches can support larger populations, and corridors can increase immigration and rescue effects, both of which can reduce local extinction risk.
12. An island loses half of its forest to development. Which outcome is most consistent with island biogeography theory?
Explanation. Reducing habitat area can shrink populations and remove habitat types, which often increases extinction risk and can lower equilibrium species richness.
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FAQ
What is island biogeography in AP Biology?
Island biogeography explains patterns of species richness on islands or habitat patches using immigration, extinction, island size, isolation, and dispersal ability.
How does distance affect island species richness?
Closer islands usually have higher immigration rates because organisms and propagules are more likely to reach them from source populations.
Why do larger islands usually support more species?
Larger islands often have more habitats and larger populations, which can support more species and reduce the chance that populations disappear by random events.