During the last ice age, an ice sheet split the southern and northern populations of R. tarandus in North America. Explain how this ice sheet influenced the evolution of R. tarandus so that the two different subspecies arose.
Assess the relative importance of natural selection and genetic drift in producing the different fur colours of the two subspecies of reindeer.
Assess the relative importance of natural selection and genetic drift in producing the different body sizes of the two subspecies of reindeer.
Hybridisation has occurred between individuals of the two subspecies that now live in the area previously covered by the ice sheet. Comment on how the hybrid populations compare with the pure subspecies in terms of genetic variation and potential to adapt to climate change.
Outline how practical techniques could be used to test the hypothesis that migratory behaviour in reindeer has a genetic basis.