This muscle presents significant divergences as to its frequency in different humans groups [ 2, 7, 9– 12]; it can be absent in some individuals of the genera Pan and Gorilla [ 6], but it is always present in Hylobates, Pongo [ 9, 10], and Sapajus [ 13], and its absence has not been reported in other primates.
One aim of the Descent of Man was to show that the differences in facial features, body types, and skin color of different human groups that would have been impossible or difficult to explain as environmental adaptations were the product of sexual selection for beauty, which different groups perceived differently.
In the early and mid-1800s there was considerable scientific debate about the origins of humans and of human races, and about just how different human groups were.
From these observations it is reasonable to conclude that different human groups might also have strikingly disparate response rates to specific disease treatments.
In the spring and summer, the pace picks up as different human groups enter the story; most disappear, like Australopithecus afarensis, a creature whose brain was larger than a chimpanzee's but much smaller than ours.
The environmental characteristics of the upper Lerma river basin and the accessibility to the Balsas midelevation basin from its southern margins facilitated the settlement of different human groups since the early history of Mesoamerica.
Like other plants and animals that spread through what Alfred Crosby called "the Columbian Exchange", once out of their zone of origin, turkeys were subject to selective breeding by farmers, which means that while all turkeys in the world are cousins, they include groups with very different appearances and features prized by different human groups.
We have alternative ways of speaking of human diversity available to us, some of which are on vivid display in Amo's early life and work, and which focus on rather more interesting features of different human groups than their superficial phenotypic traits.
one and the same person can belong to several very different human groups.
As Bryan Norton puts it, the world faces a global challenge to see whether different human groups, with widely varying perspectives, can perhaps "accept responsibility to maintain a non-declining set of opportunities based on possible uses of the environment".
Sowell's newest work is the last of a trilogy (Race and Culture, 1994; Migrations and Cultures, 1996) in which he gives his answer to one of the most troubling, and taboo, questions of modern times: why the achievements of different human groups vary so dramatically.
