sunlight → producers → consumers → heat
🌿AP BIOLOGY STUDY GUIDE
Unit 8: Ecology Study Guide
Study population growth, species interactions, energy flow, nutrient cycles, biodiversity, and disruption.
8 key ideas8 flashcards5 practice questions
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Do not treat them the same.
organisms ↔ air, water, and soil
Key ideas to know
Start with the relationships between ideas. Then close the notes and explain each one from memory.
- 01
Energy enters most ecosystems through photosynthesis and is lost as heat across trophic levels.
- 02
Population growth depends on births, deaths, immigration, and emigration.
- 03
Carrying capacity is the population size an environment can sustain under current conditions.
- 04
Species interactions can affect survival, reproduction, and distribution.
- 05
Greater biodiversity can support ecosystem stability and recovery.
- 06
Matter cycles through ecosystems even though energy flows in one direction.
- 07
Density-dependent and density-independent factors affect populations differently.
- 08
Disturbance can alter succession, species composition, and ecosystem processes.
PART OF THE AP BIOLOGY GUIDE
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Open the full AP Biology guide →Two ideas worth correcting now
NOT QUITE
→Energy cycles through an ecosystem
USE THIS INSTEAD
Matter cycles, but usable energy moves through the system and leaves mainly as heat.
NOT QUITE
→Carrying capacity is a permanent number
USE THIS INSTEAD
It can shift when resources, habitat, species interactions, or other conditions shift.
Flashcards
Answer before opening each card. The effort to retrieve is part of the learning.
1What shape describes unrestricted population growth?Show answer ＋
A J-shaped exponential curve.
2What limits logistic growth?Show answer ＋
Density-dependent factors increase as the population approaches carrying capacity.
3Why is less energy available at higher trophic levels?Show answer ＋
Organisms use much of the energy they obtain, and energy leaves the system as heat.
4What is a keystone species?Show answer ＋
A species with an effect on its ecosystem that is large relative to its abundance.
5What is primary succession?Show answer ＋
Community formation in an area that begins without soil.
6What is net primary productivity?Show answer ＋
Gross primary productivity minus the energy producers use in cellular respiration.
7What is competitive exclusion?Show answer ＋
Two species using the same limiting resource in the same way cannot coexist indefinitely.
8What is an edge effect?Show answer ＋
A difference in conditions or species interactions near the boundary of a habitat.
Explain it in your own words
Use the answer as a check after you have written or spoken your response.
01Why do food chains usually contain few trophic levels?
Energy transfer is inefficient, so too little usable energy remains to support many higher levels.
02How can removing one predator alter many species?
A trophic cascade changes prey abundance and can spread through several feeding relationships.
03Why can habitat fragmentation reduce biodiversity?
It shrinks connected habitat, isolates populations, and increases edge effects.
04How can a fertilizer runoff pulse affect a lake?
Extra nutrients can increase algal growth, and decomposition can then lower dissolved oxygen.
05Why can two populations with the same size have different growth rates?
Their age structure, birth rate, death rate, immigration, and emigration may differ.
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