"I do not believe that man has adapted in order to learn to work in groups for survival"
When man first began to pass on cultural information rather than simply reproductive information, "survival mechanisms" moves from the strictly biological to the logical. Even before Man became a meat eater and was thus able to support a larger brain, there was inherent advantage to living in small groups. To survive they needed to eat, and they needed to avoid being eaten. Both these tasks are facilitated by some form of association. Of course, a biological family provides a prototypical instance of this, which leads naturally to an evolutionary direction.
The following site offers a rather encompassing, clear, and unelaborate reference to our history. I have copied just a small interesting portion of it. But it is all very interesting and worth reading...
raceandhistory.com
Man the scavenger
Switch back to meat:
The evolution of genus Homo is thought to have been influenced to a significant extent by the practice of basing a greater portion the diet on the ingestion of meat than that obtained by either the great apes or members of genus Australopithecus. Thus, we are Homo the meat eaters.
However, were our ancestors who began this practice also the hunters of the meat they began to consume in increasing amounts?
In fact, there is a high likelihood that concepts of man the hunter are simply another example of man the arrogant.
Instead, it is more likely that early Homo obtained their meat by stealing it from those much more adept at killing (leopards, for example). That is, evidence that early Homo hunted is not nearly as robust as evidence that early Homo scavenged.
Scenario:
One interpretation of the evidence goes like this:
Early Homo was omnivorous (eaters of both vegetables and meat) and living in riparian habitats (rivers, which provided trees for refuge from predators).
There they gathered plants which constituted the core of the early Homo diet.
Especially during times of few (dry season, for example) scavenging took on particular importance.
One source of meat was the bone marrow of large kills (brought down by lions and saber toothed tigers), a source of meat available only to them and the hyenas. Also potentially available were leopard kills, the scavenging (actually stealing) of which was a role early Homo alone may have filled.
"The earliest hominids probably scavenged and took small prey with their hands, as chimpanzees and baboons do. Only their next step was unique: they began to use tools to butcher large carcasses that nonhuman primates cannot exploit. The difficulty of this leap (to the use of tools to butcher) belies the charge that scavenging offers no challenge that might select for human qualities. . . Scavenging is not at all easy for a slow, small, dull-toothed primate. To locate scavengeable carcasses before others did, we had to learn how to interpret the diverse cues to the presence of a carcass in riparian woodlands. They include the labored, low-level, early-morning, beeline flight of a single vulture toward a kill; vultures perched in mid-canopy rather than at the crown of a tree, where they nest; appendages of a concealed leopard or of its kill dangling from a branch; and tufts of ungulate hair or fresh claw marks at the base of a leopards favorite feeding tree. At night, the loud 'laughing' of hyenas at a fresh kill, the panicked braying of a zebra being attacked, the grunting of a frightened wildebeest---all serve notice of where to find an abandoned carcass when morning comes." (p. 94-95, Blumenschine and Cavallo, 1992)
Scavenging, brains, and hunting:
The bigger the primate brain, the more complex, varied, extensive, and higher quality is the food supply potentially available to the possessing organism.
Having access to a high quality food supply supplies two things:
it allows the support of a big brain, which, gram for gram, is the most metabolically expensive tissue animals have
it maintains the species as generalists and therefore potentially adaptable to new situations and environmental conditions
Genus Homo thus apparently expanded the primate tendency toward exploit generalized food supplies by focusing it additionally toward the difficult art of scavenging meat.
This may have in turn driven the evolution of an even larger brain which ultimately set the stage for the later development of man the hunter.
Hunting, of course, is an even more difficult strategy for obtaining a varied diet, which in turn may have supplied one component of the further selection pressure necessary to drive additional brain expansion.
Homo habilis
Big brained bipedal apes:
Genus Homo combined strikingly large brains with the bipedalism of the australopithecines.
The reason for the development of larger brains likely has an ecological explanation (see man the scavenger, above, for one possibility or aspect).
Early genus Homo:
The first relatively well accepted member of genus Homo is Homo habilis, handy man.
Compared with Australopithecus africanus, H. habilis more resembled with respect to:
brain size
brain form
teeth size
teeth form
Perhaps of greatest significance, however, was H. habilis's significantly increased reliance on the use of tools for eating and survival.
"H. habilis was nearer to modern humans than A. africanus is with respect to size and form of the brain, size and morphology of the teeth, and the adjustment to an erect posture, as well as in many other features. . . (also) H. habilis, it seems, became obligate stone toolmakers and users, whereas the late robust and hyper-robust australopithecines might have been only facultative toolmakers and users (able to make and use stone tools, but equally able to survive without them). . . The robust and hyper-robust australopithecines (may have) prepared their food predominantly in their mouths, chewing it between their greatly expanded upper and lower cheek teeth, whereas H. habilis prepared its food with hand-held stone tools prior to eating." (p. 158, 159 Tobias, 1992)
Homo erectus
Most successful Homo species:
Humanity had truly almost arrived as H. erectus replaced H. habilis as the dominant Homo species (resulting in the extinction of H. habilis).
H. erectus, in terms of time spent on the earth, was the most successful of Homo species. She:
lived in large groups
controlled fire
had a much more sophisticated "tool kit" than all animals that came before her
spread her kind throughout the old world
She was also the most culturally advanced creature of any previous.
Homo sapiens
H. erectus was replaced by an archaic form of H. sapiens.
Anatomically modern Homo sapiens
100,000 years of anatomical moderness:
Anatomically modern H. sapiens began replacing the various archaic forms approximately 100,000 years ago.
All of humanity is descended from these anatomically modern H. sapiens.
Cultural evolution:
Anatomically modern H. sapiens have the duel distinction of:
having raised cultural evolution, the practice of passing non-genetic information from parent to child, to higher levels than any other animal could dream of
of using that skill to drive (largely not only without abatement but to an increasing extent) her entire home planet to the brink of ecological/environmental collapse.
Clearly humans have become very good at what we do. Perhaps we have gotten a little too good?
Man's future:
This is not a course on anthropology so we will not consider humanity's achievements beyond this except as they pertain to biological sciences.
We will also avoid speculating on mankind's biological future except to leave you pondering these important considerations:
Only with a knowledge of evolutionary biology can one successfully subvert evolution.
The one indisputable rule of evolution is that all species go extinct.
Profound extinction of lineages usually occurs as a consequence of failure to adapt to changing environments (especially when those changes are abrupt).
Consistently, seemingly omnipotent human civilizations of the past have had a nasty tendency of collapsing due to self inflicted (or perpetuated) environmental change. Indeed, our entire world-wide civilization is just as dependent as it ever has been on the existence of a few inches of top soil and the fact that more often than not the rains come at appropriate times.
Modern man, at an unprecedented rate, is changing her environment for the worst. Are you prepared to survive a changing environment? Are any of us? Could you survive even a month in the absence of a local food market and a few gallons of gasoline refined from oil mined half-way around the world? In a world of so many, could any of us?
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"Is this your definition of life?"
No. It is a notable characteristic of life. Here arer some definitions:
lifeinuniverse.org |
