Southern Africa - Day 25 (Part 2)

Thursday, 6 February 2020 - South Africa 

So, this is what I learned from the museum - as much of the information that I could remember, anyway:

About 250 million years ago when land and oceans were forming on the surface of the earth, all the land in the world were joined together in 1 super-continent known as Pangaea. Then about 200 million years ago, this super-continent separated into 2: the southern part is known as Gondwana and the northern part is known as Laurasia. Then, what is now the Indian subcontinent broke off from the east coast of Africa and moved north, slamming into Asia and creating the Himalayas. This had profound effects for the African climate, drying out air currents, reducing rainfall and eventually causing savannah to replace forests. In the history of Earth, there has actually been 5 major extinctions altogether, dinosaurs were the fifth at 65 million years ago. 

Human evolution was not a single chain of adaptations - it was more like a tree or bush of parallel lineages. Some lineages were successful, or able to adapt to changing environments, while others were not and became extinct (theory of natural selection). Our family tree probably began with an ape species that lived between 8 and 7 million years ago. The same species is thought to have given rise to the African apes. 

The earliest claim for a hominid so far is Sahelanthropus tchadensis, found in Chad in 2001 and dated at about 7 million years old. There are some others found in Ethiopia. About 4 million years ago, another species of hominids known as the Australopithecus anamensis was found, and this was followed by Australopithecus afarensis about 3.6 and 3 million years ago, best represented by the Ethiopian fossil “Lucy”. 

Then the family tree branches out to Paranthropus (which means ‘parallel to human’) and Australopithecus africanus. Both these hominids walked upright and lived at about the same time as our direct predecessors in the genus homo. But Paranthropus became extinct about 1 million years ago. The Australopithecus africanus had human-like teeth and hands but also some ape-like features like a small brain, flattened nose and forward projecting jaws. They lived between 3 and 2 million years ago; Mrs Ples and the Taung Child are examples.

The earliest species of the genus homo, our most direct ancestors, appeared about 2.3 million years ago. Distinct because of their bigger brains and more prominent noses, ultra-adaptable, omnivorous. There were many species of homo: the first was homo habilis (1.9 million years ago, had the mental and physical capacity to fashion primitive stone tools, fossils found in Kenya and Tanzania); homo ergaster (1.7 million years ago, advance tool use and ability to harness fire for cooking and warmth which allowed them to leave Africa for cooler climates); homo erectus (in Asia - the Java man, Peking man); homo antecessor (found in Spain; Latin for ‘pioneer’ or ‘explore’, about 800,000 years ago); homo sapiens idaltu (in Ethiopia and South Africa, from 160,000 to 250,000 years ago); homo heidelbergensis and homo neanderthalensis (Europe, tall, big-boned, heavy built, 120,000 years ago); homo sapiens (about 70,000 to 200,000 years ago in Africa; some of the earliest fossils have been found in Ethiopia and South Africa). 

These immediate ancestors looked like us and were fully “human” - they could think and communicate symbolically, were self-aware, and they created complex social and cultural ways of life. DNA analysis shows that modern humans spread out of Africa perhaps 60,000 to 40,000 years ago and replaced the last, now “dead branches” of the family tree in Europe and Asia.