Topic 5B: Evolution, Natural Selection And Speciation

Question 1

Explain how a new species may have evolved due to allopatric speciation(5)

Answer 1

• Geographical isoloation due to physical barriers stops interbreeding and gene flow
• random genetic mutations cause variation in the population which allows some to do so and so (1)
• these individuals {will be selected for / are more likely to survive and reproduce} (1)
• the proportion of individuals in the population with this mutation will change over time (1)
• over many generations these populations become genetically distinct from the above ground population (1) (reproductively isolated)