The Living World 8th Edition by George Johnson

تمرين 14

Has Brain Size Increased as Hominids Evolved?
As noted in this chapter, brain size has become progressively larger as hominids evolved. Interestingly, Neanderthal fossils ( left in the photo below) typically have larger brains than fossils of modern humans ( right in photo below), about 1,650 cubic centimeters (cc) for Homo neanderthalensis versus about 1,500 cc for H. sapiens. Does this suggest that Neanderthals were smarter than us?
the graph to the right explores the evolution of hominid brain size by plotting the age of each major type of hominid versus its brain size (that is, the volume of the skull cranium's interior). For each type of hominid, there is some variation in cranial volume among the fossils that have been described, and a typical value is presented (the number in parentheses by each point). The value for H. neanderthalensis , for example, is plotted as a typical 1,650 cc, even though a skull found in the amud cave of israel (see page 469) is 90 cc larger. Some paleontologists consider H. ergaster to be a variant of H. erectus , and H. heidelbergensis and H. neanderthalensis to be variants of H. sapiens , but for the sake of this analysis, the "splitters" view is presented. While the question used to be controversial, most anthropologists now feel that H. neanderthalensis and H. sapiens are separate species, both descended from H. heidelbergensis (however it is named).
Further Analysis What key unverified assumption does this conclusion depend upon? If you do not accept this further conclusion, why then do you think brain size has evolved as rapidly as it has in the genus Homo ?