Populations: Speciation and Genetic Drift

• Reproductive separation in two populations can cause accumulation of differences in gene pools • New species form when these genetic differences prevent populations from interbreeding and producing fertile offspring • Allopatric and sympatric speciation are processes by which new species arise from existing ones • Genetic drift can alter allele frequency in small populations • Students should be able to explain why phenotype variation exists within a species’ population • They should understand the significance of genetic drift in small populations • They should know how natural selection and isolation can result in changes in allele and phenotype frequency and create a new species • An understanding of how evolutionary change over time has resulted in species diversity is necessary • Students must be able to apply correct concepts to given examples and be specific to the context of the question.