1.7 Ecological Relationships and Energy Flow
Fieldwork, sampling, competition, adaptation, food webs, energy loss, decomposition, carbon and nitrogen cycles, minerals and biodiversity.
How to study for CCEA GCSE Biology
Learn each process as a structure-and-mechanism chain, use data with units, and prepare every prescribed practical from planning through conclusion and evaluation.
Core concepts
Concept 1
Random quadrat sampling estimates abundance without choosing favourable sites, while a belt transect tests change along an environmental gradient.
Exam cue: Match the sampling method to whether the task estimates a whole area or change along a gradient.
Concept 2
Energy enters most ecosystems through producers and decreases through trophic levels because not all biomass is eaten or transferred to growth.
Exam cue: Separate energy flow, which is not recycled, from nutrient cycling, which returns materials to the environment.
Concept 3
Decomposers and microorganisms recycle materials through carbon and nitrogen cycles, while human activity can alter climate, nutrient loading and biodiversity.
Exam cue: Link a human action to a mechanism, an environmental change and a population or biodiversity consequence.
Risk pitfalls and guardrails
Placing decomposers outside food webs or treating them as a trophic level with no energy source.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a biological mechanism with a vague purpose statement.
Assuming a pyramid of numbers must always be upright.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a biological mechanism with a vague purpose statement.
Explaining eutrophication as fertiliser directly poisoning every aquatic animal.
Guardrail: Do not import an England board, Single Award or Double Award structure, and do not replace a biological mechanism with a vague purpose statement.
Memory anchors
Population
All organisms of one species living in a habitat at a given time.
Random quadrat
An unbiased sample used to estimate abundance across an area.
Belt transect
A sequence of quadrats used to study distribution along a gradient.
Trophic level
An organism's feeding position in a food chain or web.
Decomposer
An organism that secretes enzymes, digests externally and absorbs products.
Eutrophication
Nutrient enrichment drives algal growth, decomposition and oxygen depletion.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Ecologists count every bluebell of one species within a study area. What ecological group do these bluebells form?
Which factor is abiotic?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
What is Pass Harbor?
Completely free exam prep for 247 UK exams.
- Practice questions
- Flashcards
- Study guides
- Mock exams
- No registration
- No paywall
- Start instantly
“No more expensive exam prep. Quality study tools should be accessible to everyone.”