Natural selection arises as a result of?

1. Analyze the question We are asked what natural selection "arises as a result of". Natural selection is the process by which organisms best suited to their environment survive and reproduce more successfully than others.

2. Explain the concept Natural selection (Darwin's theory) depends on three things:

• Variation among individuals in a population
• Struggle for existence (competition for limited resources)
• Survival of the fittest, with favourable traits passed to offspring

The key requirement is variation. Without differences between individuals, there is nothing for the environment to "select". The ultimate source of new variation is gene mutation (along with recombination during sexual reproduction). Mutations create new alleles, and natural selection then acts on them.

3. Step-by-step solution

• A. Gene mutation: It produces new heritable variation. Selection acts on this variation, so natural selection arises from it. ✔
• B. Change of habitat: It can change which traits are favoured, but it is an environmental pressure, not the source of the variation.
• C. Reduction in population: This is often a result of selection or other factors, not its cause.
• D. Climate change: It is a selection pressure that can drive natural selection, but it is not the basic origin of the heritable differences that selection works on. It is also only one of many pressures.

Of all the options, gene mutation is the only one that supplies the raw material for natural selection, so it is the best answer.

4. Answer A. gene mutation

5. Exam tip Remember the chain: Mutation → Variation → Selection → Adaptation → Evolution. If a question asks about the origin of variation or what selection "arises from", think mutation. If it asks about what drives selection, think environmental factors such as climate, predation or competition.