1.4 Interdependence of organisms: How do organisms live together?
Analyse energy transfer, feeding relationships and biotic or abiotic influences within ecosystems.
How to study WJEC GCSE The Sciences
Move from a scientific model to a prediction or method, collect or interpret evidence, show quantitative working and finish with a conclusion whose limits match the data.
Core concepts
Concept 1
Construct and interpret food chains, food webs and trophic relationships.
Exam cue: Identify the unit, entered tier, supplied reference material, command word and relevant scientific enquiry skill.
Concept 2
Explain why energy and biomass decrease through trophic levels.
Exam cue: Use the direction of energy transfer and the named environmental factor to explain a population pattern.
Concept 3
Investigate distributions and distinguish biotic from abiotic influences.
Exam cue: Use scientific terminology, show quantitative working with units, and connect conclusions to data and the stated model.
Concept 4
Official subtopics: 1.4.1 Relationships within an ecosystem; 1.4.2 Biotic and abiotic factors within an ecosystem.
Concept 5
Scientific enquiry and mathematical skills apply in this topic; bold amplification is Higher Tier only.
Risk pitfalls and guardrails
Reading food-chain arrows as the direction of predation rather than energy transfer.
Guardrail: Do not import outgoing 3430QD content, another science route, a fixed required-practical list or unsupported tier and connection assumptions.
Recalling a fact without applying it to the observation, data, practical method or unfamiliar context.
Guardrail: Use the live secure pack: Task A may use groups of up to three; Task B is individual and highly controlled. Two enquiries are selected by the centre from three.
Importing content, required practicals, tier rules or paper structure from the outgoing WJEC or another awarding-body route.
Guardrail: Bold amplification is Higher-only. Units 1-6 may mix tiers, but Unit 7 is untiered.
Memory anchors
Ecosystem
Interactions between organisms and their physical environment in an area.
Trophic level
A feeding position in a food chain or web.
Producer
An organism that makes biomass using energy, usually by photosynthesis.
Biotic factor
A living influence on organisms in an ecosystem.
Abiotic factor
A non-living physical or chemical environmental influence.
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
Which sequence shows increasing levels of ecological organisation? Follow the direction of energy transfer and distinguish living from non-living influences. Check whether the conclusion exceeds the evidence.
Which is an abiotic factor affecting a plant community? Follow the direction of energy transfer and distinguish living from non-living influences. Distinguish correlation from a supported causal explanation.
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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