Compare natural and artificial selection
Both processes involve inherited variation; the primary selection pressure differs.
Section 18.3 · Selection
Exam scope and assessment notes
Extended only (Supplement) · Biology 0970, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked; human subject-teacher review, supervised practical competence and cumulative assessment remain pending. Cambridge states that IGCSE 0970 has the same subject content as IGCSE 0610, with 9–1 grading. This StudyForA pathway maps the 2026–2028 syllabus only. This 9–1 graded qualification is available only in a limited number of administrative zones. Confirm that your centre can enter you for this code and exam series with Cambridge International. Cambridge has published a separate syllabus for 2029. StudyForA has not reconciled that version yet; this page supports exams in 2026, 2027 and 2028 only.
Before you begin
- Use the stated case, sample and assumptions. Diagrams and numerical records in this pathway are original teaching models; written answers are self-checked.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What is the key difference between natural and artificial selection?
What you will learn
- Compare environmental and human selection pressures
- Identify the process from a described breeding or habitat context
Original selection schematic. Population counts and scenarios are supplied teaching models; they are not field observations.
| Stage or record | Meaning |
|---|---|
| Wild population | Environment affects relative reproduction |
| Breeding programme | People choose parents and target |
| Shared basis | Inherited variation and offspring |
| Key question | Who or what changes reproductive contribution? |
Compare environmental and human selection pressures
Natural selection occurs when environmental conditions influence the relative survival and reproduction of inherited variants. Competition for resources can be part of that context. Individuals better suited to the stated conditions have a greater chance of producing offspring, which may inherit associated alleles.
Artificial selection occurs when people deliberately choose organisms with desirable features as parents. The chosen parents are crossed; offspring showing the target feature are selected for later generations. The human-selected criterion could be crop seed size or a domesticated animal feature.
Identify the process from a described breeding or habitat context
Both processes depend on variation and reproduction, and both can alter how common inherited traits become over generations. Their key difference is not whether an environment exists—both happen in environments—but whether human choice of breeding parents is the primary selection mechanism described.
Humans can also affect natural selection by changing habitats, so identify what the question says is driving the reproductive difference. Do not call every change involving people artificial selection: a road may alter habitat without people choosing which organisms reproduce. Conversely, deliberate breeding is artificial selection even though the organisms also face environmental conditions.
Pause and explain
A road changes habitat, but people do not choose organism parents. Is this automatically artificial selection?
Worked example
In one case, drought changes which wild plants leave more seeds. In another, a farmer chooses parents for seed size. Compare the selection process in each.
Show the worked solution
- For the wild population, identify the environmental condition affecting reproduction.
- For the crop, identify the human-selected parent criterion and repeated breeding step.
Answer Drought-related differential reproduction in a wild population describes natural selection if inherited variation and allele transmission are supported. The farmer’s deliberate parent choice describes artificial selection.
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Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Wild moth colour proportions shift as a habitat darkens and predator detection differs. What process may be involved, and what evidence links it to natural selection?
Give me a hint
The habitat is acting through environmental reproductive outcomes.
Compare my reasoning
- Natural selection is possible if colour variation is inherited.
- Compare reproduction and allele transmission across generations.
This may be natural selection if inherited colour differences are linked to differential reproduction in that habitat and associated alleles pass to offspring.
Look for these in your work
- Process conditional
- Evidence links named
A breeder chooses parent dogs for a stated coat feature and selects offspring for the next mating. Identify the process and two steps.
Give me a hint
Human parent choice identifies the process.
Compare my reasoning
- The breeder selects parents for a desired feature.
- Offspring are assessed and selected for later breeding.
This is artificial selection: deliberate parent choice, crossing/mating, then offspring selection; repetition across generations continues the process.
Look for these in your work
- Process and criterion
- Offspring step
A conservation project releases a pesticide that changes insect survival, while a separate breeding programme chooses parents for pesticide tolerance. Compare carefully.
Give me a hint
One activity changes the environment; the other directly chooses breeding parents.
Compare my reasoning
- The pesticide may create an environmental selection pressure.
- The breeding team performs artificial selection only if it chooses parents and offspring.
The environmental change can contribute to natural selection among insects; deliberate choice of parents for tolerance is artificial selection. The description should not confuse exposure with parent choice.
Look for these in your work
- Both mechanisms separated
- Human selection criterion
Common mistakes
- Defining artificial selection as any human presence
- Claiming natural selection has no human-influenced environment
- Ignoring shared inheritance and reproduction
What can you explain now?
A road changes habitat, but people do not choose organism parents. Is this automatically artificial selection?
Compare with the explanation
No; habitat change alone is not deliberate breeding
Artificial selection requires human choice of parents for desired features.
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Make it stick
Without your notes, compare environmental and human selection pressures and identify the process from a described breeding or habitat context. Explain the mechanism, use the given population or breeding records and state what the evidence does not establish.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.