Cambridge O Level Environmental Management: Ecosystems, Biodiversity and Fieldwork — Revision Notes (5014, 2027-2029)

Syllabus edition note. These notes follow the Cambridge O Level Environmental Management 5014 syllabus for exams in 2027, 2028 and 2029.

Topic 5 of Cambridge O Level Environmental Management (5014) joins ecology to practical skills. You learn how energy and carbon move through ecosystems, why forests are cleared and why they should be managed sustainably, how biodiversity is conserved, and how to plan a fieldwork investigation that collects reliable data. Paper 2 often sets a fieldwork method or a data table from an investigation, so the practical part deserves as much revision as the theory.

Full explanations: ecosystems study guide. Test yourself: ecosystems practice questions.

Syllabus coverage (5014, 2027-2029)

Sub-topic	Outcomes	Focus
5.1 Ecosystems	5.1.1-5.1.9	Terms, biotic and abiotic factors, interactions, pollination, photosynthesis, energy flow, pyramids, respiration, carbon cycle
5.2 Forest ecosystems	5.2.1-5.2.4	Six causes and seven impacts of deforestation; sustainable management
5.3 Managing biodiversity	5.3.1-5.3.2	Ten conservation strategies; benefits and limitations
5.4 Fieldwork investigations	5.4.1-5.4.5	Scientific method; random and systematic sampling; seven techniques

5.1 Ecosystems: build it from the bottom up

Level of organisation. Organism → population (one species in an area) → community (all species in an area) → ecosystem (community plus abiotic environment). Each species has a habitat (where it lives) and a niche (its role). A species is a group able to breed and produce fertile offspring.

Feeding roles. Producers make food by photosynthesis → primary consumers (herbivores) → secondary consumers → tertiary consumers; an apex predator has no natural predators. Decomposers break down dead matter. Predators hunt prey.

Abiotic factors: temperature, water, oxygen, carbon dioxide, salinity, light, pH.

Interactions

• Native species belong in an area; invasive species are introduced and spread, often out-competing natives.
• Competition for limited resources; predation; pollination.

Pollination: pollen moves from an anther to a stigma by insect pollinators or by wind → fertilisation → seeds and fruit.

Two equations to learn as a pair

• Photosynthesis: carbon dioxide + water → glucose + oxygen (sunlight energy; chlorophyll captures light).
• Aerobic respiration: glucose + oxygen → carbon dioxide + water (energy released).

Energy flow

• About 10% of energy passes to the next trophic level.
• Losses: movement, respiration, digestion and excretion.
• Pyramids of energy narrow upwards every time; pyramids of numbers can be inverted (many insects on one tree).

Worked example. Phytoplankton in a lake fix 80 000 kJ. Zooplankton receive 8 000 kJ, small fish 800 kJ, pike 80 kJ. If a fourth consumer were added it would receive only 8 kJ - too little to support a viable population, which limits food chain length.

Carbon cycle - six processes: photosynthesis (air to plants); feeding (plants to animals); respiration (organisms to air); decomposition (dead matter to air); fossil fuel formation (buried remains to coal, oil, gas); combustion (fuels to air).

5.2 Forest ecosystems: causes → impacts → management

Cause	Typical example
Logging and timber extraction	Hardwood for furniture
Subsistence and commercial farming	Shifting cultivation; cattle ranching; plantations
Roads and settlements	Access roads open forest to settlers
Rock, ore and mineral extraction	Open-pit mines
Hydro-electric power stations	Reservoirs flood valleys
Climate change	Drought and fire stress forests

Impacts: habitat loss; biodiversity loss; soil erosion and desertification; silting and flooding; global warming; changed rainfall; genetic depletion.

Sustainable management of forests balances the needs of the environment, wildlife and humans while conserving forests for future generations. Needed because forests regulate climate (carbon sinks and stores), drive the water cycle (interception, uptake, transpiration, less run-off), control floods, prevent soil erosion, are a genetic resource, supply food, medicine and raw materials, and support recreation, ecotourism and education.

5.3 Managing biodiversity: protect, store or regulate

• Protect in the wild: national parks and reserves; wildlife corridors; sustainable harvesting; sustainable forestry; ecotourism.
• Store or breed outside the wild: seed banks; zoos and captive breeding.
• Regulate people: international cooperation against animal trade; regulation of trade in vulnerable and endangered species; classifying species as threatened, endangered or extinct.

Discussion pattern: in-the-wild methods protect whole ecosystems but need enforcement and funding; storage and breeding protect genes but not habitats; regulation works only with monitoring and cooperation between countries.

5.4 Fieldwork: the investigation cycle

1. Aim and hypothesis - a testable prediction.
2. Plan - sampling strategy, technique, questionnaires or surveys; a pilot study to test the method.
3. Variables - independent (changed), dependent (measured), controlled (kept the same).
4. Repeats and replicates - improve reliability and allow a mean.
5. Record, analyse, identify anomalies, conclude.

Sampling	Benefit	Limitation
Random	Unbiased	May miss rare species or parts of the site
Systematic	Shows change along a gradient	May miss what falls between sample points

Technique	Best for	Limitation
Pitfall trap	Ground invertebrates	Predators may eat catch; check often
Pooter	Small insects	Only very small animals
Sweep net	Insects in grass	Misses animals near the ground
Quadrat	Plants, slow animals	Percentage cover is an estimate
Transect	Change across an area	Time-consuming
Aerial photos and drones	Large or inaccessible areas	Cost; cannot see under canopy
Automated sampling	Continuous data, camera traps	Equipment cost and data handling

Common mistakes and exam traps

• Writing that producers “make energy” - they convert light energy into chemical energy in glucose.
• Calling decomposers consumers.
• Confusing a control variable with a control experiment.
• Saying a pilot study collects the final results - it tests the method first.
• Giving zoos as protecting habitats.

Frequently asked questions

Why do food chains rarely have more than five levels? Only about 10% of energy passes up each level, so too little energy remains to support animals at higher levels.

What is a pilot study? A small trial run of the method, used to find and fix problems before the main data collection.

How does deforestation change rainfall? Fewer trees means less transpiration, so less water vapour enters the atmosphere and local rainfall can decrease.

Official syllabus

Cambridge O Level Environmental Management (5014) syllabus for 2027, 2028 and 2029 - official syllabus PDF, Topic 5.