The importance of genetic drift in causing changes in allele frequency in small populations
Genetic drift is random chance changing how common an allele is in a population. It has the biggest effect when a population is small.
Real World
When cheetah numbers crashed to fewer than 7,000 individuals, genetic drift removed much of their genetic variation — today almost all cheetahs are so genetically similar they can accept skin grafts from unrelated individuals.
Exam Focus
Distinguish drift from natural selection: drift is random and non-directional, not linked to advantageous alleles.
Evaluation Scaffold
A four-step framework for high-quality evaluation. Use this for 'assess', 'evaluate', and 'to what extent' questions.
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