Question

In part II, Figure 1, Crabtree reproduces a chart showing the expansion of human cranial volume over the last 2.5 million years. How could this argument for ancestral superior intellectual capacity as compared to today, be effectively challenged?

A) The Homo sapien ancestral lineage as shown does not necessarily provide for a direct relationship to existing modern Homo sapiens. That is, the data points do not necessarily correspond to a direct ancestral line from which our species evolved.

B) There is no correlation between cranial size and intelligence. The fact that our ancestors had large cranial volumes does not mean that they were capable of complex problem solving.

C) Crabtree has misinterpreted the data in Figure 1. In fact, the figure shows that modern human endocranial volume has been constant over the last 2 500 000 years before present

D) There is no evidence that written language and spoken language have evolved before the appearance of the earliest spears. Moreover the fact that chimpanzees can be observed using spears suggest that such tools have nothing to do with increased cranial volume.

Answer 1

The cranial volume is measuring by neuroimaging intelligence testing now a days.The cranial volume increased along with the evolution human ancestors.But ,the expansion in cranial volume were stopped after Homo neanderthalensis.It has the largest cranial volume .Latest study showed that ,cranial volume volume is decreasing over the few thousand years .

Certain studies demonstrated that there is some relation between intelligence and cranial volume.IQ has more relation with gray matter volume in the parietal lobe (attention) and frontal lobe(sensory coordination) in male whereas it correlates in the brocas's area and frontal lobe in female. Endocranial volume is generally related with size of the body .The reason for evolution of brain is  not well explained.

It is interesting to note that small mammals have large brain to body ratio than the large mammals .The studies showed that the languages are not developed suddenly and it was evolved through thousands of years.One cannot imagine how the liguistic system had evolved into such a complexity.Society see languages as a learned equipment to communicate with each other.Certain group of scholars believed that the emergence of languages as the result of certain social transformation. however the evolution language is correlates with the emergence of H.sapiens.