Study Notes
Ecosystems are complex systems involving interactions between living organisms and their environment, with energy flow and nutrient cycling. They support biodiversity and provide essential services for human wellbeing.
- Ecosystem — a community of living organisms interacting with their physical environment. Example: A forest with trees, animals, and soil.
- Biome — a large ecological area with distinct climate and vegetation. Example: Deserts, forests, grasslands, and tundras.
- Ecological Succession — the gradual change in species composition in an ecosystem over time. Example: Forest regrowth after a fire.
- Climax Community — a stable and mature ecosystem stage in succession. Example: A mature forest with stable species composition.
- Gross Primary Productivity (GPP) — total rate of photosynthesis in an ecosystem. Example: All organic matter produced by plants.
- Net Primary Productivity (NPP) — biomass available to consumers after plant respiration. Example: Energy stored in plant tissues.
- Ecological Pyramids — graphical representations of numbers, biomass, or energy across trophic levels. Example: Pyramid of energy showing energy flow through an ecosystem.
Exam Tips
Key Definitions to Remember
- Ecosystem
- Biome
- Ecological Succession
- Climax Community
- Gross Primary Productivity (GPP)
- Net Primary Productivity (NPP)
- Ecological Pyramids
Common Confusions
- Difference between primary and secondary succession
- Why energy pyramids are always upright
Typical Exam Questions
- What is an ecosystem? A community of living organisms interacting with their environment.
- How does energy transfer between trophic levels? Energy is transferred inefficiently, with about 90% lost at each level.
- What characterizes a climax community? A stable ecosystem with relatively constant species composition.
What Examiners Usually Test
- Understanding of ecological succession stages
- Ability to interpret ecological pyramids
- Knowledge of energy flow and productivity in ecosystems