Edexcel GCSE Geography A (1GA0) · Ecosystems, Biodiversity & Management
Mini-Lesson
Ecosystems, Biodiversity & Management
This mini-lesson covers Ecosystems, Biodiversity & Management (Topic 3): the world's biomes, the tropical rainforest and UK deciduous woodland, how nutrients cycle, why biodiversity matters, the threats forests face, and how they can be managed sustainably.
Work through each screen, answer the questions as you go (multiple-choice, short-answer and games) and collect ⭐ stars. Press Start when you're ready.
Global ecosystems
Biomes and where they are
A biome is a large-scale global ecosystem, defined mainly by its climate (temperature and rainfall). Their distribution follows the global atmospheric circulation:
Tropical rainforest — near the Equator, where rising air brings hot, wet conditions all year.
Hot desert — around 30° N and S, where sinking air makes it hot and dry.
Taiga (boreal / coniferous forest) — in the cold high latitudes of the northern hemisphere.
Tundra, temperate forest, grassland — in between, set by their own climates.
Key idea: climate is the master control on biomes — but soils, altitude and drainage cause local variation too.
Tropical rainforest
The tropical rainforest
The rainforest is hot (~27 °C all year) and very wet (over 2000 mm rain a year). It has a layered structure and clever adaptations:
Trees compete for light: tall trunks reach the canopy; drip-tip leaves shed heavy rain; buttress roots give support in thin soils.
Nutrients cycle fast: dead leaves rot quickly in the heat and are taken straight back up by the trees, so most nutrients are stored in the living plants, not the soil.
Quick check
Rainforest nutrients
?Where is most of the nutrient store held in a tropical rainforest?
UK deciduous woodland
UK deciduous woodland
Woodland like the New Forest or Epping Forest is a small-scale UK ecosystem, with a temperate climate (around 4–17 °C, roughly 1,000 mm of rain a year). It contrasts sharply with the rainforest:
Climate — four clear seasons; a growing season of around 7 months, far shorter than the rainforest's year-round growth.
Plants — broadleaf, deciduous trees (oak, ash, beech, elm) forming a canopy around 20–30 m high; they shed their leaves in autumn to survive the cold winter, below them a herb layer (e.g. bluebells) and a dark, damp ground layer.
Biodiversity — moderate: lower than the rainforest's huge variety, but higher than colder biomes, since trees and animals must adapt to cold winters (hedgehogs hibernate, squirrels store food, many birds migrate).
Nutrients — cycle at a moderate pace: each autumn's leaf fall returns nutrients to a fertile brown earth soil (about 30 cm deep), so — unlike the rainforest — more nutrients are stored in the litter and soil than in the living trees.
Compare: rainforest = hot, wet all year, hugely biodiverse, nutrients mostly in the living biomass. UK deciduous woodland = four seasons, moderate biodiversity, nutrients mostly in the leaf litter and soil.
Match it
Match the feature to the biome
Tap a feature on the left, then tap the biome it belongs to on the right.
Biodiversity
Why biodiversity matters
Biodiversity is the variety of living things in an ecosystem. Forests provide vital goods (things we use) and services (things they do for us):
Goods — timber, food, fuel, medicines (many drugs come from rainforest plants).
Services — storing carbon (regulating climate), producing oxygen, cycling water and nutrients, and protecting soils.
High biodiversity makes an ecosystem more resilient and is a genetic library we can't replace.
Threats
Threats to forests
Forests, especially the rainforest, are under pressure from:
Deforestation for cattle ranching, soya and palm-oil farming, logging (timber) and mining.
Roads and settlement opening up remote forest.
Climate change, which brings more drought and fires; and in UK woodland, historic clearance for farmland and development.
Why it matters: deforestation releases stored carbon (worsening climate change), destroys habitats and biodiversity, and — because rainforest soils are thin — quickly leaves infertile, eroded land.
Explain it
Your turn — impacts of deforestation
✎Explain two ways that deforestation of the tropical rainforest harms the environment. Use the words carbon, biodiversity and soil.
Model answer
Cutting and burning trees releases stored carbon as CO₂, adding to the greenhouse effect and climate change.
Destroying habitats reduces biodiversity, so many plant and animal species are lost.
With no tree cover, heavy rain washes away the thin soil (leaching and erosion), leaving infertile land.
Selective logging — only mature trees are felled, leaving the forest to recover.
Ecotourism — small-scale, low-impact tourism that gives locals income from a living forest.
Agro-forestry and replanting; protected areas / national parks.
International agreements and consumer schemes (e.g. FSC-certified timber, debt-for-nature swaps, REDD+).
Sort it
Sustainable or unsustainable?
Tap an action, then tap the box it belongs in.
♻️ Sustainable
⛔ Unsustainable
Quick check
Comparing the biomes
?Compared with the tropical rainforest, why does UK deciduous woodland have lower biodiversity?
Recap
The key ideas to know
Biomes: large ecosystems set by climate; distribution follows global circulation.
Rainforest: hot & wet, layered, huge biodiversity, fast nutrient cycling (nutrients in biomass).
UK deciduous woodland: seasonal climate, moderate biodiversity, nutrients cycle via autumn leaf fall (nutrients mostly in the soil/litter, not the biomass).
Biodiversity: provides goods (timber, medicine) and services (carbon store, water & nutrient cycling).
Threats: deforestation for farming, logging, mining; climate change & fires.