OCR GCSE Geography B Sustaining Ecosystems: a complete overview of biomes, rainforests and polar environments

What this topic actually demands

Sustaining Ecosystems is the living-world strand of Component 1, Our Natural World. It runs from the basic workings of an ecosystem, through the global pattern of biomes, to a detailed study of two contrasting environments: the tropical rainforest and the polar regions. OCR's enquiry style frames it as a question, and the examiners test two linked skills: precise knowledge of how ecosystems work and adapt, and the ability to evaluate how a fragile biome can be used and managed sustainably.

This guide walks through the topic in specification order, then sets out the exam patterns OCR repeats. Each part has a matching dot-point page with practice questions; this overview ties them together.

Ecosystems and biomes

The topic opens with the structure of an ecosystem: producers, consumers and decomposers, food chains and webs, the one-way flow of energy (about 10 percent passing to each level) and the recycling of nutrients. It then covers the global distribution of biomes, linked to climate and the global atmospheric circulation: tropical rainforest at the wet Equator, hot desert at about 30 degrees, temperate biomes in the mid-latitudes, and polar and tundra at high latitudes.

The tropical rainforest

Tropical rainforests are studied in detail: the hot, wet climate, the four-layer structure, the rapid nutrient cycle (nutrients in the biomass, not the thin soil), and the plant and animal adaptations (drip-tips, buttress roots, lianas, camouflage). The topic then covers the causes and impacts of deforestation (ranching, logging, mining, roads; biodiversity and soil loss, carbon release) and sustainable management (selective logging, ecotourism, debt-for-nature swaps, protected areas).

Polar environments

Polar and tundra environments are the contrasting biome: extreme cold, low precipitation, permafrost, and a simple, fragile ecosystem with low biodiversity. Adaptations include thick fur, blubber and low-growing plants. The topic covers the opportunities and challenges for people (fishing, oil and gas, tourism, research, against cold and remoteness) and the threats, above all climate change, which melts ice and thaws permafrost.

Managing ecosystems sustainably

Finally, the topic draws the studies together: why ecosystems matter (goods and services), the threats they face, and local and global strategies for managing them, from community conservation and ecotourism to international agreements such as the Antarctic Treaty. The key idea is balancing development with conservation.

How this topic is examined

A typical OCR profile for Sustaining Ecosystems:

• Short answer. Defining ecosystem terms (food web, permafrost), describing biome distributions, and reading climate graphs and maps.
• Adaptation and process questions. Explaining how a plant or animal is adapted, or how nutrients are recycled, linking feature to condition.
• Case-study questions. Using the rainforest and polar environment with named facts.
• Extended Assess and Evaluate answers. Judging sustainable management, comparing local and global strategies, or assessing the climate-change threat, with a balanced conclusion and SPaG marks at stake.

Check your knowledge

A mix of recall and applied questions covering the topic. Attempt them under timed conditions, then check against the solutions.

1. Explain how energy and nutrients move through an ecosystem. (4 marks)
2. Explain why the distribution of biomes is closely linked to climate. (4 marks)
3. Explain two ways plants are adapted to a tropical rainforest. (4 marks)
4. Explain why rainforest soils are thin and infertile despite the lush vegetation. (3 marks)
5. Explain how deforestation can lead to soil erosion. (4 marks)
6. Explain how an animal is adapted to survive in a polar environment. (4 marks)
7. Explain why polar ecosystems are described as fragile. (4 marks)
8. Assess whether local or global strategies are more effective at managing ecosystems sustainably. (6 marks)