← Biology syllabus

United StatesBiology

Unit 8: Ecology

7 dot points across 7 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

Why is biodiversity important for the health and stability of ecosystems?

Topic 8.6 Biodiversity: explain how biodiversity contributes to ecosystem stability and resilience.
A focused answer to AP Biology Topic 8.6, covering species and genetic diversity, how diversity supports ecosystem stability and resilience, the effects of low diversity, and a worked example using a diversity comparison.
9 min answer →

How do species interact within a community?

Topic 8.5 Community Ecology: explain the types of interactions between species in a community and their effects on the species involved.
A focused answer to AP Biology Topic 8.5, covering competition, predation, the niche, symbiosis (mutualism, commensalism, parasitism), keystone species and trophic relationships, with a worked interaction example.
10 min answer →

How do natural and human disturbances disrupt ecosystems?

Topic 8.7 Disruptions to Ecosystems: explain how natural and human-caused disruptions affect ecosystems and how ecosystems respond.
A focused answer to AP Biology Topic 8.7, covering natural and human disturbances, invasive species, habitat loss, climate change, ecological succession, and how ecosystems respond and recover, with a worked example.
10 min answer →

How does population density affect the factors that limit growth?

Topic 8.4 Effect of Density of Populations: distinguish density-dependent from density-independent factors and explain how each limits population size.
A focused answer to AP Biology Topic 8.4, covering density-dependent factors (competition, predation, disease) and density-independent factors (weather, disasters), how each regulates populations, and K-selected versus r-selected strategies, with a worked example.
9 min answer →

How does energy flow through an ecosystem, and why is it lost between levels?

Topic 8.2 Energy Flow Through Ecosystems: explain how energy flows through trophic levels and why energy is lost between levels.
A focused answer to AP Biology Topic 8.2, covering trophic levels, food chains and webs, the 10 percent rule, energy pyramids, productivity, and why energy decreases up the chain, with a worked energy-transfer calculation.
10 min answer →

What determines how populations grow and how large they become?

Topic 8.3 Population Ecology: explain exponential and logistic growth, carrying capacity, and the factors that regulate population size.
A focused answer to AP Biology Topic 8.3, covering exponential and logistic growth, carrying capacity, growth rate calculations, and the factors that shape population size, with a worked growth-rate calculation.
11 min answer →

How do organisms respond and behave in their environment?

Topic 8.1 Responses to the Environment: explain how organisms respond to environmental cues through behavior and signalling, and how these responses affect survival and reproduction.
A focused answer to AP Biology Topic 8.1, covering innate and learned behavior, responses to environmental cues, communication and signalling, cooperative behavior, and how responses affect fitness, with a worked example.
9 min answer →