Question

Can you explain how the following items provide evidence for human evolution? • Reptile jaw bones not present in human jaws Hox genes Muscle absent in some people's arms Muscles connected to ears Goosebumps Tailbone • Grasp reflex in infants

Answer 1

Reptile jaw bones are co-opted to form a part of the hearing apparatus of the human.

Hox genes are common to most of the organisms and they help in the basic layout of the body i.e. head to tail organization.

Muscle connected to ears are now very tiny and weak. Once they have a significant role in the ancestors where they pivot their ears to and fro.

The muscle which is absent in some people's arm is palmaris longus muscle. It is absent in 15% of the people and it do not have any significant role in gripping.

Goosebumps are the evidence that human evolution comes from the ancestors having body hair like that of apes and chimpanzee.