Cambridge IGCSE·Co-ordinated Sciences 0654·Biology
Variation Selection
Key knowledge — Variation Selection
Key facts & rules
- Continuous variation: range of values (e.g. height, mass) — controlled by many genes + environment.
- Discontinuous variation: distinct categories (e.g. blood group, tongue rolling) — usually one gene.
- Natural selection: heritable variation + struggle for existence + differential reproduction = evolution.
- Darwin's theory: individuals with favourable variations survive and reproduce more → those alleles become more common.
- Selective breeding: humans select parents with desirable traits → breed together over generations.
- Evidence for evolution: fossil record, comparative anatomy, DNA comparisons.
- Antibiotic resistance: bacteria with resistance allele survive treatment → reproduce → resistance spreads (natural selection).
IGCSE Biology — Variation & selection
490 Cambridge IGCSE 0654 biology past paper questions on variation & selection, organised by subtopic. Pick a subtopic to start practising.
About variation & selection on IGCSE 0654
Continuous and discontinuous variation, adaptation, natural selection, and selective breeding.