The Descent of Man Volume 1 Chapter II - On Manner of Development of Man from some Lower Form Part 4

In which the gradual increase and modification of the human skull and brain are carefully examined, alongside the peculiar loss of bodily hair and the disappearance of the tail, all considered through the lens of natural selection and functional adaptation. It is further observed that despite man's apparent physical weaknesses, his intellectual faculties and social qualities have collectively ensured his survival and advancement amid the struggles of existence.