Human Ancestors

Natural polymers are far more complex materials, being exclusively "organic", that is, products of life (cellulose, proteins, DNA,...). Nevertheless, as nature seems to have formed (size, weight, hardness, etc.) several natural polymers (wood, bones, ivory, etc.) in such a way as to be almost immediately usable by our ancestors, they were most probably the bases of the first human tools. The commonly widespread conception that polymers are the youngest "materials" in the historical world is not true, but, strictly speaking, only applies to synthetic polymers, which were discovered about 100 years ago, early in the XXth century. 

It seems that our early human ancestors may have used grass, which (20) was easily found and ready to use, to floss between their teeth. As Hlusko suggests in the journal Current Anthropology, Toothpicking with grass stalks probably represents the most persistent habit documented in human evolution. ... 

The study of human remains has long been the most direct method of understanding the detailed lives of our ancestors as individuals. The methods of forensic science and palaeopathology have been applied for many years to determine age, sex, stature, nutritional status and cause of death, and to detect evidence of some diseases. Increasingly, DNA is being used to determine kinship. It is, however, no exaggeration to say that entire new vistas have been... 

The closest we ever come to the physical presence of our ancestors is the excavation and study of human bone, and it is, therefore, not surprising that... 

Fridlund (1994) and Russell (1994) offer detailed and important critiques of the notion of universality of facial expressions. However, the inadequacy of experimental methods does not gainsay the likelihood that human expressions evolved from those of our primate ancestors, given their early and stereotypic appearance, apparent mediation by midbrain limbic nuclei (Buck, 1988, pp. 93—98), documentation by observational research in various cultures, and resemblance to those of other species. Certainly, however, Fridlund is correct that these expressions vary markedly with culture and context, to an extent perhaps not covered by Ekman s notion of display rules. 

The presumed immutability of the Jews became a staple of American science by mid-century as well, even though slavery and the question of Negro citizenship still dominated racial discussion. In Types of Mankind (1855) Josiah Nott remarked that the well-marked Israelitish features are never beheld out of that race The complexion may be bleached or tanned. . . but the Jewish features stand unalterably through all climates. In Natural History of the Human Races (1869) John Jeffries, too, argued that the Jews have preserved their family type unimpaired and though they number over five million souls, each individual retains the full impress of his primitive typical ancestors. 23 And of course we have already seen where these observations on Jewish racial integrity tended in the age of eugenics. 

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