There is evidence that not only have there been – in the far past – periods of time that human evolution has occurred rapidly for some brief, brief with respect to the dominant rate of evolution (slow) period of time. Further, there is now recent evidence that the rate of human evolution has been increasing over the last 10 thousand years. The question is, is there a connection between this recent increase in rate and the rapid but brief rate of evolutionary “jumps” in the far past, and the human epigenome with its ability to be effected by environmental change?
Some Ancient Evidence of Rapid Evolutionary “Spurts”
Richard Leakey and Roger Lewin, authors of “The People of the Lake”, first Avon printing 1979, have taken evidence of fossils and discard piles from various archeological sites in the Great Rift Valley in eastern Africa, and deduced from many of these, the life-style of proto humans dating from 3 million years ago. Richard Leakey is eminently qualified to conjecture as to the nature of the life-style of the progenitors of homo sapiens, since he has spent his entire life researching this topic.
Richard Leakey is one of the sons of the famous Louis and Mary Leakey team of anthropological-archeologists, who made pivotal discoveries of fossils and evidence of habitation of proto-humans in the Olduvai Gorge in Africa. These discoveries convinced the world that the progenitors of homo sapiens originated in Africa. The ideas and information provided by Richard Leakey are in part, conjectural. But – giving credit to the effort of a lifetime and the devotion of Richard Leakey to the field of cultural anthropology, archeology, and paleoanthropology.
Evidence of The Life-Styles and Activities of our Ancestors
Richard Leakey’s descriptions regarding the details of life and the nature of the manner in which life was lived by the proto humans in the time before homo sapiens are the results of the study of skeletal fossils and evidence of discarded tools, and discarded animal bones and other fossilized remnants of food both animal, nuts and other vegetable and fruit.
Richard Leakey has garnered much credence for his descriptions of the prehistoric life of these progenitors. He is a recognized world authority in his field. His ability to reconstruct the details of the daily life of even the oldest of the human progenitors is quite uncanny. He derives all of this reconstruction from the evidence found at the archeological sites within a relatively small area. Thus to be able to describe in detail the life-style of the former inhabitants, our progenitors.
How the Life-Styles of Our Ancestors Affected their Evolution
3.5 million years ago our ancestors, proto-humans had a gatherer-hunter economy, lived in small groups of 25 and belonged to a tribe of such groups that numbered no more than 500 individuals. There was a division of labor – in that the women gathered nuts, fruits, and other such vegetables, grains, and shoots, along with small grubs and other sources of protein. The men hunted game, to supply meat. proto-humans were omnivores, they ate meat, greens, and fruit of all kinds.
Life-style and environmental effects played a role that promoted evolutionary changes. During this time of the evolution of our ancestors, their brains grew from 500cc to nearly 1600cc. Our ancestors were evolving at a rate that was much greater than their progenitors. From this, came the rapid development of proto-human culture. As each new tool was invented and developed, their brain sizes were growing and their divisions of labor were being refined and began the formation of much more complex cultures and life-styles.
The Evolution of Modern Humans
During this time, evolution of the proto-humans kept pace. As changes in culture and general knowledge of the groups evolved, so did the rate of evolution. At times – there were brief but rapid changes in the rate of evolution. These occurred: when our progenitors learned to walk upright, when a new class of tools was invented; when major changes to life-styles and ways of “making a living”; and in general, whenever a major change to the environment occurred; and if the tribe moved to an area with a different climate and there were different animals that became their source for meat.
Our proto-human ancestors evolved into homo sapiens about 40 to 50 thousand years ago. The culture developed by homo sapiens soon outdistanced all others developed by animals, primates, and the proto-humans. Homo sapiens descended from their pro-genitors, and evolved into modern humans about 40 to 50 thousand years ago. From that time onwards, homo sapiens has achieved an appearance that is in evidence to this day.