Study Notes
Interactions between living organisms involve the transfer of energy and nutrients through food chains and food webs. A food chain is a linear sequence of organisms where energy is transferred from one organism to another. Example: Grass → Rabbit → Fox → Decomposer.
- Food web — a network of interconnected food chains showing the complex feeding relationships in an ecosystem. Example: A rabbit can be eaten by both a fox and an eagle, forming a web.
- Herbivore — an animal that gets its energy by eating plants. Example: A rabbit eating grass.
- Carnivore — an animal that gets its energy by eating other animals. Example: A fox eating a rabbit.
- Decomposer — an organism that gets its energy from dead or waste organic matter. Example: Fungi breaking down dead leaves.
- Ecosystem — a unit containing all organisms and their environment interacting together in a given area. Example: A lake with fish, plants, and bacteria.
- Trophic level — the position of an organism in a food chain or food web. Example: Producers are at the first trophic level.
Exam Tips
Key Definitions to Remember
- Food chain: A linear sequence of organisms where energy is transferred.
- Food web: A network of interconnected food chains.
- Trophic level: The position of an organism in a food chain or web.
Common Confusions
- Confusing food chains with food webs; remember, webs are more complex.
- Misunderstanding the role of decomposers; they recycle nutrients, not consume living organisms.
Typical Exam Questions
- What are the first organisms in a food chain? Producers, such as plants.
- What is the difference between the food chain and the food web? A food chain is linear, while a food web is a network of interconnected chains.
- What role do humans play in a food chain? Humans can be primary, secondary, or tertiary consumers.
What Examiners Usually Test
- Understanding of energy flow through trophic levels.
- Ability to differentiate between food chains and food webs.