The Modern Human

 

In the last instalment in this series, we touched on origins, adaptability and migration which can be read here.

Around 1.8 million years ago, the Homo erectus migrated out of sub-Saharan Africa. The Homo heidelbergensis formed colonies in northern Africa around 500,000 years ago. Even though large dispersal of population continued around Africa, this was the time when migration came to a brief halt. Separate peoples started living side by side in regions and intermingling of genes supervened.

But 100,000 years ago, another major dispersal took place which is pivotal in our history. The Homo sapiens sapiens – an anatomically modern human species started migrating out of sub-Saharan Africa and into new worlds untouched.

A few examples of Homo sapiens migration:

  • 50,000 Years ago – Australia is reached by boats.
  • 33,000 Years ago – Islands in the western Pacific Ocean are colonised.
  • 15,000 Years ago – The Americas are reached.
  • 4,500 Years ago – As continental ice sheets retreat, expansion into the Arctic ensues.
  • 2,000 Years ago – Human settlements begin in deep Pacific islands.
  • 1,200 Years ago – With no disrespect to Captain James Cook, New Zealand is reached.

DNA sampling tells us that Homo sapiens originated in Africa between 200,000 and 140,000 years ago. And by 28,000 years ago, they are the sole human species on the planet as the Neanderthals faced extinction.

The earliest known skulls of modern looking humans were discovered in the Klasies River caves in South Africa and from the Omo basin in Ethiopia. Carbon dating estimates them to be 130,000 years old.

klasies_river_caves.jpg
Klasies River caves in South Africa

100,000 Years ago, migrating northwards toward Africa, these early people began dispersing. This was followed by a process that scientists term as “bottlenecking”, meaning the total population of the dispersed people, remained small and relatively constant for thousands of years.

There is a plausible theory as to why that happened. It is postulated that the eruption of the Toba volcano in the island of Sumatra in Indonesia might have been a deciding factor for this genetic bottleneck. It was an absolute catastrophe that occurred approximately 75,000 years ago that caused a global volcanic winter that lasted between six and ten years and a 1000-year-long cooling phase. Although researchers believe the next super-eruption of Toba is still thousands of years away, it is still generating magma and its reservoir is increasing beneath the caldera. So as a precaution, let’s be safe out there.

The genetic bottleneck also affected other mammals such as the Bornean orangutan, the central Indian macaque and the Eastern Africa chimpanzee.

Age of Prosperity

The rapid expansion of humans was in full flow about 50,000 years ago. As described in the previous installment, sharpened stone tools dating back to 2.5 million years ago that were discovered in Ethiopia showcased the Australopithecines’ adaptability towards technology. But the Homo sapiens were much more sophisticated in their ways.

Weapons that were multi-component in nature have been discovered in various regions. The spear in particular, was a thing of genius. They were made with sharp stone blades that were fixed to wooden shafts and handles. Not much difference in shape and structure to spears of later years.

Archaeological evidence also suggests proof of textiles and baskets with organised camp sites, underground food vaults and trading networks. Raw materials, stone in particular, were now being traded over hundreds of kilometres.

Our great cousins, 0.3% DNA removed

Although the Homo sapiens excelled in weapons and trade, they were by no means the only human species walking the earth 50,000 years ago. In East and south-east Asia, lived the descendants of the Homo erectus who migrated to that region out of Africa over a million years earlier. But perhaps the best known peoples of the early human population were the Neanderthals with whom we share 99.7% of our DNA.

_87554309_c0263754-neanderthal_model-spl

They had a robust build, with distinctive and large heads, large teeth and powerful bodies that were well suited for cold weather. Their brains were as large as modern humans and they were adept at adapting to several climatic conditions. They were effective hunters and used their tools to hunt down beasts like bison and horse.

Their most hominine behaviour was the burial of the dead, a method of disposing off dead bodies that is still followed by several faiths today. A 60,000 years old skeleton appearing to be carefully laid down in a grave was discovered at the Kebara Cave in Israel. This proves some degree of social malleability among the Neanderthals.

kebara2cast

Works of art such as cave paintings, engraved stones, figurines, ornaments, etc. discovered at several sites around the world are a testament to their humane side.

By the time the Neanderthals and the Homo erectus were extinct, modern humans had colonised Australia for 20,000 years. It is still unclear why an entire species faced extinction. The Neanderthals were expert hunters of large Ice Age animals. But when climate changed, and those animals themselves faced extinction, the Neanderthals may have faced starvation.

As mentioned earlier, the Homo sapiens were much more sophisticated than the Neanderthals. They had long distance trade networks, which might have been convenient when food was scarce due to climate change. The Neanderthals were helpless.

There are a lot of factors pointing towards the source of their extinction. Some would argue, that the Neanderthals are not extinct at all. They exist within us as anyone whose ancestry is from outside of Africa, where the Neanderthals never lived, carries a tiny bit of Neanderthal DNA in their genes.

As these distant cousins of ours started disappearing, modern humans had already colonised many lands across the globe and eventually, established themselves as the sole hominine species in planet earth.

 

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