Which of the following is true of the evolution of the human brain?
A) The human brain is smaller than that of any other primate.
B) Comparisons of brain size within the primate family require an adjustment for body size.
C) The size of primate brains have shrunk over the course of evolutionary history.
D) Primate brain size increases depended on the elimination of duplicate master genes.
E) Inactivation of the ghrelin gene likely makes chimpanzee brains larger than human brains.

Question

Quizplus · Accepted Answer

Comparisons of brain size within the primate family require an adjustment for body size. This is because larger animals tend to have larger brains, so it's important to account for differences in overall body size when comparing the relative size of different primate brains.

Answer: D
 Primate brain size increases depended on the elimination of duplicate master genes. This theory, known as the gene dosage hypothesis, suggests that increased brain size in primates occurred as a result of gene duplication events that allowed for additional copies of genes related to brain development to evolve and become specialized.

Answers A, C, and E are all false. The human brain is actually larger than the brains of many other primates, especially when adjusted for body size; primate brains have not generally shrunk over the course of evolutionary history; and inactivation of the ghrelin gene would not be expected to affect brain size in chimps or humans.

Which of the Following Is True of the Evolution of the Human