Talk Report

HUMAN ORIGINS – Professor John Compton

A light moment came at the close of John Compton’s talk when Jan proposing a vote of thanks announced   ‘Now at last I know where I come from!’.

We are not the pinnacle of evolution. Although we have special traits, all life forms are special. Our human origins go back over 5 million years. Today our world population is about 7 billion. Originally there were 3 or 4 species of bipedials inhabiting the earth, now only homo sapiens, namely ourselves who walk on two feet. There was Paranthropus – nutcracker man, homo malidi, with a larger brain, recently discovered in Gauteng.

60000 years ago the then hunter gatherers based in Africa dispersed during the Great Expansion. By 50000 years ago people filled the world, having moved first northwards, then to the west and the east, and down even to Australasia.  We mingled with our cousins in the North but eventually wiped them out. The world population was then about 5 million, roughly equal to that of greater Cape Town today.

In 1798 Thomas Matthus predicted a world collapse due to population expansion. That has not happened but the question remains.  Is our world sustainable or have we reached overshoot – Apocolyptic  or Utopian?

The earliest fossil evidence of life on earth was 4000 million years ago. Written history began about 5000 years ago. The oldest discovery of stone tools dates 2.2 million years ago – in Kenya.

As mankind adapted to different environments there was an overall increase in brain size. This is a major feature in our lineage. Humans were neither fast on foot  or strong.  Stone tools became smaller and were mainly used for scavenging food from animal sources.  A bigger brain was more inventive, enabling the ability to cope with stressful climate variations and other problems. Richer food sources provided the nutrients and energy the brain needed.

The Underberg Cave in the Northern Province provides the earliest evidence of the use of fire. The camp fire had a major influence on social behaviour. It was a warm and safe place. The body of Homo Sapiens at this time had less body hair, and variable skin colour. Another important difference to the ape species was that Homo Erectus walked on two feet.  Higher levels of body fat enabled endurance running, and the sweating that went with this. Tools became less crude and bilaterally symmetrical.  Spears for thrusting evolved to spears for throwing about 280 000 years ago.

As higher calorific foods were needed to sustain development,  it was found that wetlands provided the essentials of water, diverse animal life and plants. Seafood was relatively easy to find, cook and digest, and was rich in nutrients.  Early evidence of this – about 164000 years ago – was found in a Pinnacle Point cave near Mossel Bay.  During the glacial period many areas isolated by mountains in Africa had human settlements. For example, in the North near the Atlas Mts was the narrow Mahgreb strip, while in the South near Sedgefield our ancestors enjoyed a good life with lakes, good rains, and sea life.

‘We forget most of our past, but embody all of it. Are we a unique creation?  No, we are related to all life on earth` –  John Updike.