Econstudentlog

The Human Past (i)

I’m behind on the book blogging, but it takes a lot of time and generally it’s a bit more fun to read the stuff than to reread sections in order to blog it. So anyway, I’ve mentioned the book before but I haven’t blogged any of it yet. The subtitle is ‘World Prehistory & the Development of Human Societies’ and it’s an archaeology/anthropology-textbook. I bought it at The National Museum, haven’t regretted that. As is usually the case with textbooks, it’s quite hard to quote from a book like this because there’s generally a lot of context you need to include for the quote to have any meaning, however I’ve tried to give some highlights from the first chapter and the first part of the second chapter (~first 60 pages) below:

i. “The first serious investigations of British prehistoric monuments began in the 17th century, with John Aubrey’s discriptions and plans of Stonehenge and Avebury in southern England. The first hesitant steps in the direction of proper archaeological excavation were made toward the end of the century, in northern France and Scandinavia, though much digging into ancient sites still had the aim of treasure hunting, with little or no attention to the contexts from which objects came (Bahn 1996). Systematic excavation began only in the late 18th century, when the concept of stratigraphy began to be understood. Stratigraphy – successive deposition of superimposed layers, either of natural or cultural material – laid the basis for chronological sequenses, since lower deposits should have been laid down earlier than overlying layers […] These early archaeological enquiries were innovative for their time, but were unable to overcome the most fundamental problem of prehistory: that of chronology. […] Archaeologists in the 17th and 18th centuries were increasingly able to recognize that many of the remains they were studying were pre-Roman in date, but had no way of establishing their true age. […]

It was during the 19th century that the problem of chronology began to be resolved and the study of prehistoric archaeology was finally born (Daniel 1975; Trigger 2006; Diaz Andreu 2007). Early in the century it came to be realized that archaeological materials could be sorted into sequences by means of their technology: stone tools had preceded metal ones, and among the latter, bronze had preceded iron. Thus the three-age system of Stone, Bronze, and Iron was established. […] Closer study of the artifacts led to increasing subdivision of the European “three ages” […] Thus the Stone Age was subdivided into an Old Stone Age (with tools exclusively of chipped or flaked stone) and a New Stone Age (with tools of polished stone). In the 1860s these two periods came to be known as the Paleolithic (Old Stone Age) and Neolithic (New Stone Age). The Bronze Age and Iron Age, too, were each subdivided into Early, Middle, and Late.”

ii. “anthropologists continue to seek appropriate ways of classifying different kinds of human society, so that they may be better understood and compared. One widely influential scheme was that proposed by Elman Service (1962), in which he divided human societies into four major categories:

* Bands, characterized by small groups of 25-60 individuals who are related to each other through family and marriage ties – such societies are typical of mobile hunter-gatherers;

* Tribes, generally settled farmers or pastoralist herders, numbering from a few hundred to a few thousand individuals whose identity is based on a concept of descent from a common ancestor; they are loosely organized without central control or strongly developed social hierachy;

* Chiefdoms, which may number over 10,000 individuals, in which institutionalized differences of rank and status are embedded in a hierachy of lineages ruled over by a chief; a key economic feature of chiefdom societies is redistribution, in which subordinate sectors of society pay tribute to the chief who then redistribute it to his followers;

* State societies or civilizations, in which populations reach much greater levels of size and complexity, with a centralized and institutionalized control that overrides kinship ties, and in which differences of rank and wealth are fostered and protected.

[…]

early farming societies have often been considered to have been tribal in character, whereas hunters and gatherers are imagined to have been organized into smaller-scale bands. […] Although useful as a general scheme […] this classification of human societies must be used with caution.”

iii. “For some time it had been believed that the human evolutionary pathway involved a unique combination of traits that evolved more or less comtemporaneously, namely bipedal locomotion (walking on two feet), the making of stone tools, and significant increase in brain size.
The past few decades of research have undermined this scenario, however, producing evidence that these traits did not evolve together. Rather, their appearances were drawn out in a sequence over millions of years; bipedal walking preceded the first evidence for stone tools by millions of years, and brain expansion is evident only several hundreds of thousand of years after the beginnings of stone tools.
The fossil evidence indicates that bipedal hominins emerged in Africa from an ape ancestry by 6 million years ago. A number of different hominin species – possibly a dozen – are known to have existed between then and 1.5 million years ago; our own genus, Homo (a genus being a group of closely related species), emerged fairly recently, by at least 2 million years ago. Furthermore, the fossil record suggests that at many times during the span of this time more than one hominin species co-existed, indicating evolutionary complexity and possible niche separation during this phase of our evolution, with different lineages focusing on different foods and ecological habitats, rather than a single evolving hominin line. The earliest flaked stone tools are dated to between 2.6 and 2.5 million years ago”

iv. “The two major subgroups (suborders) of primates are sometimes referred to as the “lower primates” and the “higher primates”. The lower primates, the Prosimii, are observed to be somewhat closer in morphology and function to earlier primate species, and some of them even retain such “primitive” characteristics as an emphasis on an olfactory adaption, retention of claws on some digits, and less highly developed grasping ability than is seen among the higher primates. Examples of lower primates today include lemurs, lorises, and tarsiers.
The higher primates, the Anthropoidea, show morphological traits such as heightened enlargement of the brain and development of the visual senses, which emerged later in primate evolution and are considered more altered, or “derived,” from earlier, basal primate characteristics. […]
Early primate evolution is observed in the fossil record during the early epochs of the Cenozoic period: the Paleocene and the Eocene.
The major evolution and adaptive dispersal of the primates occurred after the mass extinction event that happened 65 million years ago […]
Between 60 and 35 million years ago, primarily during the Eocene epoch (which dates to about 55 million to 35 million years ago), primates emerged that show much more affinity than earlier types to some of the lower primates among modern groups, especially the lemurs and tarsiers. […] As North America and Eurasia were still connected during much of this time, these early primates were widespread across the northern landmasses, as well as in Africa, where they may have originated. They are absent, however, in South America, since this continent had not yet joined with the North American continent. […]
Although the origins of the anthropoids probably lie within the Eocene epoch, it was during the Oligocene (about 35 million to 22 million years ago) that distinct anthropoids begin to leave prominent traces in the fossil record. […] Starting about 20 million years ago, during the Miocene, we see fossil evidence in africa for the emergence of distinct lineages of Old World Monkeys and apes. Apes (or hominoids, members of the superfamily Hominoidea) were dominant for the first several million years of this anthropoid radiation, dispersing first within the forested environments of Africa, and then into Europe and Asia, and evolving into a multitude of species over this geographic expanse. […] Ape species began to dwindle during the Miocene as the climate cooled and forests declined, while monkeys, which had been less prevalent, spread and diversified. By the end of the Miocene, about 5 million years ago, ape species were relatively few and more geographically restricted than in early Miocene times, a trend that has continued to the present. It is from this diminished, later Miocene ape stock that early human ancestors were to emerge, branching off from our last shared common ancestor with the other apes (probably the chimpanzees) apparently sometime between 8 and 6 million years ago.”

The stuff in this chapter is so cool. How the hell is ‘God did it’ a better story than this? Of course, it’s not just a story. Books like these present big chunks of the data and the methods used to analyze them, in part because authors like these actually make their living analyzing that data and applying those methods they describe. There’s a lot of evidence (though we’d always like to have more!) and it’s pretty much all of it very useful – if new evidence raises new questions, whch is so often the case, those questions nevertheless still tend to improve our understanding of the past on net; because before we asked those questions we didn’t even know that those questions were out there somewhere, needing an answer.

v. “Most tests indicate that human DNA differs from that of the chimpanzee by only approximately 1.5 percent (see p.145). On a microscopic scale also, there is remarkable chromosomal similarity between humans and chimpanzees in terms of their number (23 chromosomes in humans, 24 in great apes, with human chromosome number 2 the probable result of fusion of two chromosomes inherited from the human-chimpanzee ancestor), as well as their appearance and banding.
Taken together, the results of these diverse studies converge remarkably on basically the same branching sequence in hominoid evolution, with gibbons branching off first from the rest of the apes, followed by the orangutan and, much later, the gorilla. The chimpanzee-human divergence is now evident as the most recent of all. The genetic distance results conform remarkably well with the classification system suggested here […], with humans differing genetically from the chimpanzee by 1.5 percent, the gorilla by about 2 percent, the orangutan by 3 percent, the gibbon by 4 percent, Old World monkeys by 6 percent, New World monkeys by 12 percent, and prosimians by over 20 percent.”

vi. “There is growing evidence that changes in the earth’s climate had profound effects on the African landmass, altering temperature and rainfall and, subsequently, flora and fauna. Some of these major changes appear to relate to major changes in human evolution as well. […] the mountain ranges of the African Rift created by tectonic uplift caused by movements of the earth’s plates gave rise to a rain shadow in much of East Africa, gradually leading to drier, more open environments, particularly after the mid-Miocene, around 14 million years ago [East Africa is important because most of the main sites with early homo-remains are located in East Africa, US]. […] Early in the evolution of the African apes, by the beginning of the Miocene (around 22 million years ago), the African continent was quite different from how it is at present. Lush tropical forests and woodlands covered much of the landmass in tropical and subtropical Africa, and the Sahara Desert had not yet developed.”

September 5, 2011 - Posted by | anthropology, archaeology, books, evolution, genetics

1 Comment »

  1. […] post in the series about the book, the first is here. I’ll complete my treatment of chapter two in this […]

    Pingback by The Human Past (ii) « Econstudentlog | September 11, 2011 | Reply


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