Unit 8: Ecology

AP Biology — 8 practice questions with detailed explanations. Use the links below to open each full question page (ideal for search indexing and deep study).

Unit summary

This unit covers core ideas tested on the AP exam. Each listed item links to a standalone page with the full stem, answer choices where applicable, a step-by-step explanation, and the correct answer. Difficulty labels help you prioritize review.

Questions in this unit

In a terrestrial ecosystem, which of the following best illustrates the relationship between gross primary productivity (GPP) and net primary productivity (NPP)?hard · mcq · 1 pt
A large, continuous forest is fragmented into several smaller patches to make way for agricultural development. Over the next few decades, conservationists note a significant decline in the population size of a specific native understory plant that relies on large patches of shaded, moist soil. Which of the following is the most likely cause of this decline?medium · mcq · 1 pt
European honeybees perform a specific sequence of movements, often referred to as a 'waggle dance,' to communicate the location of a nectar source to other bees in the hive. The angle of the dance relative to the sun indicates direction, while the duration of the dance indicates distance. This behavior is best described as:hard · mcq · 1 pt
Five species of warblers, all of similar size and beak morphology, coexist in the same spruce forest. They feed primarily on insects but forage in distinct microhabitats—some hunt near the trunk, others on the inner branches, and others near the tips of the branches. Which of the following ecological concepts best explains this phenomenon?hard · mcq · 1 pt
A keystone species, the sea otter, is removed from a kelp forest ecosystem due to disease. Without the otters, the population of sea urchins, their primary prey, explodes and consumes the base of the kelp, ultimately decimating the kelp forest. Which of the following best describes the role of the sea otter in this ecosystem?medium · mcq · 1 pt
An ecosystem receives an input of 400,000 kJ of solar energy per square meter per year. If the primary producers convert 1% of this energy into biomass, and the trophic transfer efficiency between subsequent levels is 10%, approximately how much energy (in kJ) is available to the secondary consumers in this ecosystem?hard · mcq · 1 pt
Researchers monitor a population of invasive zebra mussels in a local lake. Initially, the population grows exponentially, but over time the growth rate decreases and eventually stabilizes. Which of the following best explains the stabilization of this population?hard · mcq · 1 pt
A population of white-footed mice in a mature deciduous forest experiences a significant increase in population density over a six-month period. Which of the following is most likely to occur as a direct result of this increased density?hard · mcq · 1 pt

Sample prompts

Short previews of topics covered (not full question text).

In a terrestrial ecosystem, which of the following best illustrates the relation…
A large, continuous forest is fragmented into several smaller patches to make wa…
European honeybees perform a specific sequence of movements, often referred to a…
Five species of warblers, all of similar size and beak morphology, coexist in th…
A keystone species, the sea otter, is removed from a kelp forest ecosystem due t…
An ecosystem receives an input of 400,000 kJ of solar energy per square meter pe…
Researchers monitor a population of invasive zebra mussels in a local lake. Init…
A population of white-footed mice in a mature deciduous forest experiences a sig…