AP Biology · Unit 8
Ecology
Move from organismal responses through energy, populations, communities, biodiversity, and ecosystem disruptions using evidence-based models.
Learning sequence
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Topic 8.1
Responses, Behavior & Signaling
Distinguish behavioral from physiological responses and connect signaling to fitness.
Topics 8.1–8.2
Choice Experiments & Organismal Energy
Design a defensible choice experiment, then account for how an organism spends its energy.
Topic 8.2
Trophic Transfer & Productivity
Trace energy through trophic levels and calculate transfer efficiency and productivity.
Topic 8.2
Biogeochemical Cycles
Model the water, carbon, nitrogen, and phosphorus cycles and predict the effect of a blocked step.
Topic 8.3
Population Growth
Calculate population change from births, deaths, immigration, and emigration, and model exponential growth.
Topic 8.4
Carrying Capacity & Density
Interpret logistic growth and sort density-dependent from density-independent regulation.
Topic 8.5
Community Structure & Diversity
Quantify richness and evenness, calculate a diversity index, and evaluate a sampling design.
Topic 8.5
Species Interactions & Succession
Classify interactions by sign and trace indirect effects through a trophic cascade.
Topic 8.6
Biodiversity, Resilience & Keystone Species
Explain how diversity supports resilience and analyze keystone-species removals.
Topic 8.7
Adaptation & Ecosystem Disruptions
Analyze invasive species, human impacts, and physical disturbance with evidence.
Topics 8.1–8.7
Unit 8 Assessment
Apply ecological equations, interaction models, food webs, diversity data, and disruption evidence.