4.3 Evolution: Why are organisms so different?
Connect inherited and environmental variation to natural selection and evaluate gene technologies.
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
Classify continuous, discontinuous, heritable and non-heritable variation.
Exam cue: Identify the unit, entered tier, supplied reference material, command word and relevant scientific enquiry skill.
Concept 2
Explain natural selection as a population process across generations.
Exam cue: Start with existing inherited variation, then trace differential survival and reproduction across generations.
Concept 3
Evaluate gene-technology evidence, benefits, risks and ethical issues.
Exam cue: Use scientific terminology, show quantitative working with units, and connect conclusions to data and the stated model.
Concept 4
Official subtopics: 4.3.1 Types of variation; 4.3.2 Natural selection; 4.3.3 Gene technology.
Concept 5
Scientific enquiry and mathematical skills apply in this topic; bold amplification is Higher Tier only.
Risk pitfalls and guardrails
Saying an individual evolves because it needs a useful characteristic.
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
Variation
Differences among individuals of the same species.
Natural selection
Differential survival and reproduction associated with inherited variation.
Adaptation
An inherited feature that improves success in a particular environment.
Mutation
A change in genetic material that can create a new allele.
Gene technology
Use or modification of genetic material for a defined purpose.
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 characteristic is most clearly influenced by both genes and environment? Separate inherited variation from environmental effects and reason across generations. Base the comparison on like-for-like evidence.
What is the original source of new alleles in a population? Separate inherited variation from environmental effects and reason across generations. Account for the control condition before comparing results.
Answer all questions to submit.
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Move forward only after this module is stable.
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