CAIE IGCSE Biology 18.3.1 Natural Selection with Reference Questions
Practise sequencing how inherited variation, competition and differential reproduction change allele frequencies over generations.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Exam points
- start with genetic variation within a population before environmental selection pressure acts
- link production of many offspring and competition for resources to a struggle for survival
- explain that better-adapted individuals have greater survival and reproductive success and pass alleles to the next generation
CAIE IGCSE Biology 18.3.1 Natural Selection with Reference Questions question 1
Sickle-cell anaemia is an inherited disease.
Fig. 5.1 is a photomicrograph of some blood cells from a person who has sickle-cell anaemia.
Fig. 5.1
Sickle-cell anaemia is most common in areas of the world where the infectious disease malaria is found.
Some species of the genus Plasmodium cause malaria in humans.
The distribution of sickle-cell anaemia is the result of natural selection.
Explain the distribution of the sickle-cell allele in human populations.
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