A-Level Geography: Ecosystems Revision

Ecosystems is a core part of A-Level Geography. Revise the key concepts and common mistakes below, then lock them in with the free games.

Key concepts

Trophic LevelsEnergy flow positions: producers (plants), primary consumers (herbivores), secondary (carnivores), tertiary, decomposers.

Net Primary ProductivityBiomass produced by plants after respiration; tropical rainforest highest (2200 g/m2/year), desert lowest.

Biodiversity HotspotsNorman Myers' 36 regions with 1500+ endemic plants and 70%+ habitat loss; Madagascar, Cape Floristic, Indo-Burma.

Ecosystem ServicesMillennium Ecosystem Assessment 2005: provisioning (food, water), regulating (climate, pollination), cultural, supporting.

Habitat FragmentationBreaking up of ecosystems into isolated patches by roads, farms; reduces species viability; e.g. Atlantic rainforest 12% remaining.

Rewilding KneppSussex estate restored from intensive farming since 2001; reintroduced large herbivores; turtle dove, nightingale, purple emperor returned.

Upland BritainNorthwest and west: older, harder rocks (granite, slate); higher relief; e.g. Scottish Highlands, Lake District, Snowdonia.

Lowland BritainSoutheast: younger, softer sedimentary rocks (chalk, clay); flatter relief; e.g. London Basin, East Anglia.

Tees-Exe LineDiagonal line dividing UK between upland west/north and lowland south/east; reflects geological boundary.

Glaciation LegacyLast Ice Age (until c.10,000 years ago) shaped uplands with U-shaped valleys, corries, ribbon lakes.

Coastal VarietyUK's 17,820km coast includes rocky (Cornwall), chalk (Dover), sandy (East Anglia), estuarine (Severn).

River PatternsMajor rivers (Thames, Severn, Trent) flow from uplands to lowlands; demonstrate upper, middle, lower course features.

Global heat budgetThe balance between incoming shortwave solar radiation and outgoing longwave radiation; a surplus at low latitudes and deficit at the poles drives circulation.

Global atmospheric circulationThe Hadley, Ferrel and Polar cells redistribute heat from the equator towards the poles, creating belts of high and low pressure.

Common mistakes to avoid

Questions where students often pick the tempting wrong answer — make sure you know the right one:

What actually causes earthquakes?✗ Earthquakes are caused by magma rising up to the surface. ✓ The sudden release of built-up stress along faults at plate boundaries as rocks slip past each other, generating seismic waves.

What is coral bleaching?✗ Coral bleaching is when coral is killed by sunlight bleaching its colour. ✓ When stressed (usually by warming), corals expel their symbiotic zooxanthellae (algae that provide colour and food), turning white. They can recover if stress eases, but die if it persists.

What is the difference between a megacity and a world city?✗ Megacities and world cities are the same thing. ✓ A megacity is defined by population (over 10 million); a world city is defined by global economic and cultural influence (e.g. New York, London) — so a city can be one without the other.

What is the ITCZ and why does it bring rain?✗ The ITCZ is a fixed band of permanent storms at the equator. ✓ The Intertropical Convergence Zone is where trade winds from both hemispheres converge near the equator, forcing air to rise, cool and produce heavy convectional rainfall.

What is the difference between physical and economic water scarcity?✗ Water scarcity only happens in dry countries. ✓ Physical scarcity is insufficient water supply for demand (e.g. arid regions); economic scarcity is inability to access available water due to lack of infrastructure or investment, despite water being present.

Practise Ecosystems — free games

Test yourself with these quick revision games for this topic:

▶ Two Truths, One Lie ▶ Reveal Race ▶ Connections Grid ▶ Falling Words ▶ Word Web

See all 17 games in the Subjects Arcade →

Ecosystems

Key concepts

Common mistakes to avoid

Practise Ecosystems — free games

More A-Level Geography topics