500,000 to 200,000 B.C.: Archaic Homo sapiens (our immediate predecessor) appears. These human species, of which there were a number of variants, did not last as long in evolutionary time as previous ones, apparently due simply to the increasingly rapid rate of evolution occurring in the human line at this time. Thus they represent a transitional time after the erectines leading up to modern man, and the later forms are sometimes not treated separately from the earliest modern forms of true Homo sapiens.[32]
150,000 to 120,000 B.C.: Homo sapiens neanderthalensis--or the Neanderthals--begin appearing in Europe, reaching a height between 90,000 and 35,000 years ago before becoming extinct. It is now well accepted that the Neanderthals were an evolutionary offshoot that met an eventual dead-end (in other words, they were not our ancestors), and that more than likely, both modern Homo sapiens and Neanderthals were sister species descended from a prior common archaic sapiens ancestor.[33]
140,000 to 110,000 B.C.: First appearance of anatomically modern humans (Homo sapiens).[34] The last Ice Age also dates from this period--stretching from 115,000 to 10,000 years ago. Thus it was in this context, which included harsh and rapid climatic changes, that our most recent ancestors had to flexibly adapt their eating and subsistence.[35] (Climatic shifts necessitating adaptations were also experienced in tropical regions, though to a lesser degree.[36]) It may therefore be significant that fire, though discovered earlier, came into widespread use around this same time[37] corresponding with the advent of modern human beings. Its use may in fact be a defining characteristic of modern humans[38] and their mode of subsistence. (I'll discuss the timescale of fire and cooking at more length later.)
130,000 to 120,000 B.C.: Some of the earliest evidence for seafoods (molluscs, primarily) in the diet by coastal dwellers appears at this time,[39] although in one isolated location discovered so far, there is evidence going back 300,000 years ago.[40] Common use of seafoods by coastal aborigines becomes evident about 35,000 years ago,[41] but widespread global use in the fossil record is not seen until around 20,000 years ago and since.[42] For the most part, seafoods should probably not be considered a major departure,* however, as the composition of fish, shellfish, and poultry more closely resembles the wild land-game animals many of these same ancestors ate than any other source today except for commercial game farms that attempt to mimic ancient meat.[43]
40,000 to 35,000 B.C.: The first "behaviorally modern" human beings--as seen in the sudden explosion of new forms of stone and bone tools, cave paintings and other artwork, plus elaborate burials and many other quintessentially modern human behaviors. The impetus or origin for this watershed event is still a mystery.[44]
40,000 B.C. to 10-8,000 B.C.: Last period prior to the advent of agriculture in which human beings universally subsisted by hunting and gathering (also known as the "Late Paleolithic"--or "Stone Age"--period). Paleolithic peoples did process some of their foods, but these were simple methods that would have been confined to pounding, grinding, scraping, roasting, and baking.[45]
35,000 B.C. to 15-10,000 B.C.: The Cro-Magnons (fully modern pre-Europeans) thrive in the cold climate of Europe via big-game hunting, with meat consumption rising to as much as 50%* of the diet.[46]
25,000 to 15,000 B.C.: Coldest period of the last Ice Age, during which global temperatures averaged 14°F cooler than they do today[47] (with local variations as much as 59°F lower[48]), with an increasingly arid environment and much more difficult conditions of survival to which plants, animals, and humans all had to adapt.[49] The Eurasian steppes just before and during this time had a maximum annual summer temperature of only 59°F.[50]
Humans in Europe and northern Asia, and later in North America, adapted by increasing their hunting of the large mammals such as mammoths, horses, bison and caribou which flourished on the open grasslands, tundra, and steppes which spread during this period.[51] Storage of vegetable foods that could be consumed during the harsh winters was also exploited. Clothing methods were improved (including needles with eyes) and sturdier shelters developed--the most common being animal hides wrapped around wooden posts, some of which had sunken floors and hearths.[52] In the tropics, large areas became arid. (In South Africa, for instance, the vegetation consisted mostly of shrubs and grass with few fruits.[53])
20,000 B.C. to 9,000 B.C.: Transitional period known as the "Mesolithic," during which the bow-and-arrow appeared,[54] and gazelle, antelope, and deer were being intensively hunted,[55] while at the same time precursor forms of wild plant and game management began to be more intensively practiced. At this time, wild grains, including wheat and barley by 17,000 B.C.--before their domestication--were being gathered and ground into flour as evidenced by the use of mortars-and-pestles in what is now modern-day Israel. By 13,000 B.C. the descendants of these peoples were harvesting wild grains intensely and it was only a small step from there to the development of agriculture.[56] Game management through the burning-off of land to encourage grasslands and the increase of herds became widely practiced during this time as well. In North America, for instance, the western high plains are the only area of the current United States that did not see intensive changes to the land through extensive use of fire.[57]
Also during this time, and probably also for some millennia prior to the Mesolithic (perhaps as early as 45,000 B.C.), ritual and magico-religious sanctions protecting certain wild plants developed, initiating a new symbiotic relationship between people and their food sources that became encoded culturally and constituted the first phase of domestication well prior to actual cultivation. Protections were accorded to certain wild food species (yams being a well-known example) to prevent disruption of their life cycle at periods critical to their growth, so that they could be profitably harvested later.[58] Digging sticks for yams have also been found dating to at least 40,000 B.C.,[59] so these tubers considerably antedated the use of grains in the diet.
Foods known to be gathered during the Mesolithic period in the Middle East were root vegetables, wild pulses (peas, beans, etc.), nuts such as almonds, pistachios, and hazelnuts, as well as fruits such as apples. Seafoods such as fish, crabs, molluscs, and snails also became common during this time.[60]
Approx. 10,000 B.C.: The beginning of the "Neolithic" period, or "Agricultural Revolution," i.e., farming and animal husbandry. The transition to agriculture was made necessary by gradually increasing population pressures due to the success of Homo sapiens' prior hunting and gathering way of life. (Hunting and gathering can support perhaps one person per square 10 miles; Neolithic agriculture 100 times or more that many.[61]) Also, at about the time population pressures were increasing, the last Ice Age ended, and many species of large game became extinct (probably due to a combination of both intensive hunting and disappearance of their habitats when the Ice Age ended).[62] Wild grasses and cereals began flourishing,* making them prime candidates for the staple foods to be domesticated, given our previous familiarity with them.[63] By 9,000 B.C. sheep and goats were being domesticated in the Near East, and cattle and pigs shortly after, while wheat, barley, and legumes were being cultivated somewhat before 7,000 B.C., as were fruits and nuts, while meat consumption fell enormously.[64] By 5,000 B.C. agriculture had spread to all inhabited continents except Australia.[65] During the time since the beginning of the Neolithic, the ratio of plant-to-animal foods in the diet has sharply increased from an average of probably 65%/35%* during Paleolithic times[66] to as high as 90%/10% since the advent of agriculture.[67]
Remains of fossil humans indicate decrease in health status after the Neolithic. In most respects, the changes in diet from hunter-gatherer times to agricultural times have been almost all detrimental, although there is some evidence we'll discuss later indicating that at least some genetic adaptation to the Neolithic has begun taking place in the approximately 10,000 years since it began. With the much heavier reliance on starchy foods that became the staples of the diet, tooth decay, malnutrition, and rates of infectious disease increased dramatically over Paleolithic times, further exacerbated by crowding leading to even higher rates of communicable infections.
Skeletal remains show that height decreased by four inches* from the Late Paleolithic to the early Neolithic, brought about by poorer nutrition, and perhaps also by increased infectious disease causing growth stress, and possibly by some inbreeding in communities that were isolated. Signs of osteoporosis and anemia, which was almost non-existent in pre-Neolithic times, have been frequently noted in skeletal pathologies observed in the Neolithic peoples of the Middle East. It is known that certain kinds of osteoporosis which have been found in these skeletal remains are caused by anemia, and although the causes have not yet been determined exactly, the primary suspect is reduced levels of iron thought to have been caused by the stress of infectious disease rather than dietary deficiency, although the latter remains a possibility.[68]
