Challenge Questions

1. Evidence suggests that bipedalism arose during a period of hominin history in which there was significant environmental change in eastern Africa. 

Discuss the potential adaptive advantage of bipedalism during the late Miocene period (approx 5-4 MYA) in eastern Africa that may have contributed to the development of bipedalism.

2. Humans have evolved to have a very large brain in relation to body mass. This brings with it a high metabolic cost with humans expending about 20% of their metabolic intake on the brain in comparison to 10% in most other primates. 

Discuss the relationship between the adaptive cost (metabolic and reproductive) of brain expansion and the adaptive advantage of the large brain.

3. In the past 60,000 years, development of technologies such as tools, fire and agriculture has been an emerging force which has influenced human evolution. 

Discuss the impact of key technologies on human evolution during this period and consider the potential influence of modern technologies on how humans might evolve in the future.

4. At the heart of selection is the concept of differential fitness, the idea that some individuals in a population have phenotypic characteristics that make survival and successful reproduction more likely than it is for other individuals. Yet we know that traits that might be expected to reduce fitness in human populations, such as the sickle cell anaemia, Huntington’s disease or some of the adverse consequences of bipedalism, have not been eliminated by selection. 

Discuss the possible reasons why selection during human evolution has failed to eliminate traits that might lower fitness.