Ecosystems and tropical rainforests

• An ecosystem has living (biotic) and non-living (abiotic) parts. Producers are green plants that make food from sunlight. Consumers eat other living things. Decomposers break down dead matter and return nutrients to the soil. A food web is many linked food chains.
• Tropical rainforests grow near the Equator, where it is hot and wet all year, with no dry season. They have layers: emergent, canopy, under-canopy and shrub.
• Rainforest soil is poor in nutrients. Heavy rain washes them out, and most of the nutrients are held in the plants and recycled quickly. Plants are adapted, for example with drip tips to shed water and buttress roots to hold up tall trees.
• Causes of deforestation include logging, farming, cattle ranching, roads, mining and settlement. Impacts include lost biodiversity, soil erosion and less carbon absorbed.
• Management includes selective logging, replanting, ecotourism, international agreements and debt-for-nature swaps. Learn one rainforest case study and use its facts.

Biodiversity

The variety of life in an area: the number of different species and habitats.

Producer

A green plant that makes its own food using sunlight.

Decomposer

An organism, such as a fungus, that breaks down dead matter and returns nutrients to the soil.

Deforestation

The cutting down and clearing of forest.

Ecotourism

Small-scale, low-impact tourism that protects nature and helps local people.

Debt-for-nature swap

Part of a country's debt is cancelled in return for protecting its rainforest.

• Saying the sun is a producer. The sun is the energy source. Producers are green plants.
• Thinking rainforest soil is fertile because so much grows there. Heavy rain washes nutrients out and the plants hold most of them.
• Saying palm oil comes from rainforest trees. It comes from oil palms grown on plantations, often on cleared forest land.

6 questions, 9 marks. Answer, then press Check. The marking guide explains how the marks are worked out. Nothing is saved.