Читать книгу Anthropology For Dummies - Cameron M. Smith - Страница 80

The most human-esque group — the apes — are scientifically known as the Hominoidea, or “human-like” primates. Fossil evidence puts the origins of this group around 30 million years ago, in Africa’s middle Oligocene epoch. By 6 million years ago, a new group appeared in the Hominoidea — the Hominidae; these are the apes that walked upright, and one of their kind eventually evolved into the genus Homo, which evolved into Homo sapiens sapiens: humans. So, modern human origins can be traced by fossil evidence to Africa, 6 to 30 million years ago, in the evolution of the Hominoidea. Remember, we’re not the only member of the group, and our neighbor species, such as the chimpanzees and gorillas, have also survived all this time. (Note: This classification is a bit of a gray area. Only recently have some anthropologists included chimps and gorillas in the same family as humans, as I do here; previously, Hominidae was reserved only for the bipedal primates.) The main anatomical characteristics of the Hominoidea are

 Dental formula of 2.1.2.3

 Lack of a tail

 Both arboreal and terrestrial lifestyles

 Relatively long arms (even with a terrestrial lifestyle) due to origins as tree-swingers

 Simple molars for crushing, rather than the Old World Monkey’s shear-like molars

 Relatively large body size, averaging more than 10 kilograms (30 pounds)

The Hominoidea is easily divisible into two main families, which mainly separate the Hominoidea into the somewhat monkey-like gibbons of Southeast Asia and the African apes.

 The Hylobatidae contain the gibbons of Southeast Asia, who tear through the forest canopy like Tarzan and have complex vocalizations (also like Tarzan). They’re the lightest of the Hominoidea and the least like humans: They spend a lot of time in the trees, they have relatively small brains, and they survive on a diet that, although somewhat varied, is predominantly fruit.

 Much more like humans are members of the Hominidae, the group containing the chimpanzee and gorilla (according to the DNA and skeletal evidence), and humans themselves. Generally speaking, these primates are large (averaging over 40 kilograms or 80 pounds), may live much of their lives on the ground, and have a generalized rather than specialized diet. They include Homo sapiens sapiens, a relatively large primate (averaging 70 kilograms or 140 pounds) that possesses a very large brain compared to body size and uses extremely complex behavior and tools to adapt and survive. That should sound familiar because you’re one of them.

When you think about the past, and the fossil record, and the many individual primates that lie in your own past (right back to the first primates more than 60 million years ago), remember that a lot of speciations and extinctions have occurred. Generally speaking, most species (defined in the “Biological classification” sidebar earlier in the chapter) survive only about 4 million years; most genera survive for about 20 million years. Our species, Homo sapiens sapiens, has been around for about 100,000 years. But, as I discuss throughout this book, humanity is so different from most other life forms — for an array of reasons — that this natural timescale doesn’t necessarily apply to it. Humanity has invented many ways to prevent itself from falling prey to the circumstances that cause other species to become extinct (and at the same time has invented many means of committing suicide, such as nuclear and biological weapons).