Biology · Both
Ecosystems & Interdependence
Food chains and webs, producers and consumers, biodiversity and how humans affect ecosystems.
Living things depend on each other and their environment. Food chains show feeding relationships; biodiversity matters for stable ecosystems.
Food chains and webs
• **Producer** – makes own food (usually plants by photosynthesis)
• **Primary consumer** – eats producers (herbivore)
• **Secondary consumer** – eats primary consumers (carnivore / omnivore)
• **Decomposer** – breaks down dead material (bacteria, fungi)
A **food web** shows many interlinked food chains.
Energy flows from producers → consumers; energy is lost at each level (often as heat).
Biodiversity
Biodiversity = variety of living organisms in an area.
High biodiversity helps ecosystems survive change (disease, climate).
Human activities that reduce biodiversity: habitat destruction, pollution, overfishing, climate change, introduction of invasive species.
Practice questions
Try these without looking at the answers first.
Q1.What is a producer?
Show answer
Organism that makes its own food (e.g. plant)
Q2.Name one way humans reduce biodiversity.
Show answer
Habitat destruction / pollution / overfishing / climate change (any valid)
Q3.What do decomposers do?
Show answer
Break down dead material