Discovering Religion: Episode 11 – Human Origin
The journey of human evolution began in Africa some 8 million years ago, which at the time was covered with forests from edge to edge. The primates that inhabited these lands lived in the trees, as Africa was continent-wide jungle. However, a great climate change began to take place due to plate tectonics, causing India to collide with Asia, producing the Himalayas.
The formation of such a great mountain range caused dramatic fluctuations in the weather, resulting in the biggest monsoons the Earth had ever seen. The rains stripped the air of moisture, so the air currents that finally reached Africa were no longer wet, but dry. As the rainforests retreated, a new habitat of scattered trees and grasslands took shape.
Forced from the trees, apes were required to keep up with the changing landscape by spending more time on the ground, eventually learning to walk upright. Three and a half million years ago a primate known as Australopithecus africanus dominated the African savannah, but what differentiated these apes from others is that they could stand and walk on two legs.
There were certain advantages to standing upright, one of them being an erect posture allowed them look above the tall grasses. By walking on two legs they were also able to conserve more energy, thereby allowing them to engage in other activities such as finding food and increased sexual activity. Therefore, Australopithecus was afforded better opportunities to propagate the species and expand their population by walking on two legs. Although these animals were not much more than apes that walked upright, they had great potential, and in the following generations, populations of Australopithecus evolved into new and different species.
Two million years ago there were several different species of primates that lived on the African savannah. There was Homo Habilis. Their slightly larger rivals, Homo rudolfensis.
And gorilla like Paranthropus boisei. The reason there were so many different hominid species is because there were so many varieties of food to eat.
By examining the skull of boisei we see a powerful jaw, large muscles in their cheeks, and teeth four times the size of our own. This meant they could eat the toughest vegetation, like the roots of the reeds. Their specializations made bosiei extremely successful. Even months into a dry season, where other animals would have been struggling to find food, bosiei had ample amounts of food and plenty of time to engage in other activities, such as sex.
The skull of Homo habilis on the other hand, does not display these same specialized features that allowed the boisei to survive in the harsh conditions of the dry season. To make up for the lack of specialization, they developed into inquisitive scavengers. However this was a difficult life, for although boisei knew where to find their food, a meal for habilis could be anywhere, and to find it they had to be talented investigators. For instance, the circling of vouchers meant there was a nearby carcass, rich in protein and animal fat. And unlike boisei, habilis ate meat.
Habilis was not the only scavenging primate on the savannah. Homo rudolfensis was another meat-eating primate that often rivaled habilis for territory as well as food. Although boisei were specialized at eating particular foods, allowing them to be incredibly successful even during times of drought, their success was only ensured so long as the world did not change.
But if there is one thing we can be sure of, no environment remains the same forever. Over the next several hundred thousand years new habitats replaced the old ones and new forms of life developed to exploit these habitats, causing older species that could not keep up with the change to die out. Eventually boisei became extinct, but habalis went on to be the ancestor of more advanced species of hominid.
The success of habilis lied in their savaging, inquisitive lifestyle that made them inventive and quick witted. Habalis was the first animal on Earth to be able to use stone tools.
These tools meant Habilis could live off an amazing range of different foods. And because they ate meat, Habalis was provided with the essential protein and fat that allowed the development of a larger brain. Habilis’ jack-of-all-trades way of life meant they had a better chance of surviving in an ever-changing world. And its this trait that has lived on and become an essential part of us.
One and a half millions years ago in Southern Africa there appeared a new species hominid, called Homo Ergaster. Ergaster lived in some of the hottest conditions in Africa, and henceforth they developed one of the most sophisticated cooling systems of any animal on Earth. Long, modern looking noses cooled and moisten the air as they breathed. Hairless bodies were more efficient at allowing the escape of excess body heat. And millions of tiny glands in their skin meant they no longer had to pant to control their temperature, they sweat.
In addition to these adaptations, Ergaster evolved a larger brain that allowed them to engage in vocal communication, the first hominids to have developed a type of speech. Up until this point, no other member of the animal kingdom had been able to piece together seemingly unrelated clues about their environment into a cohesive understanding of the world. For instance, there has never been another animal, beside ourselves, that is able to look at hoof prints and differentiate them from other patterns in the mud.
However, Ergaster was the first to recognize these prints for what they are, understanding they were made by an animal and in which direction it traveled — this advancement in their cognitive ability allowed them to successfully hunt and track their prey. Ergaster was also able to make stone tools, like this axe, which was heavy and powerful, yet precise enough that it could cut. It shows planning and vision, and because these tools are found all over africa it shows these people could learn the secretes of tool making from each other.
Ergaster did not have a perminant home, but instead drifted from place to place hunting and gathering their food. Because Ergaster had evolved such an advanced ability to understand their environment and developed tools to aid their acquisition of food they were the first species of hominid to leave their ancestral lands of Africa to begin populating the rest of the world. They started by following the course of the Nile River, across Africa and into the Middle East.
With their numbers growing, they traveled further and further in searched for food, eventually reaching Asia, as far as southern China. Their epic journey took thousands of years, in fact they traveled so far that when we find their fossilized remains on the Asian Continent they had evolved into a new species, called homo erectus. Interestingly, when we find the remains of homo erectus we rarely find the stone axes used by their cousins in Africa. It could be that Erectus found another tool easier to work with, and in this area it would have been all around them, bamboo.
Half a million years ago, around the same time hominids first discovered fire, another species of human could be found all over Europe and Africa, they were called Homo heidelbergensis. These hominids had brains almost as large as our own. Examination of the morphology of the outer and middle ear suggests they had an auditory sensitivity similar to modern humans and very different from chimpanzees. This means they were able to differentiate between a variety of sounds in a rudimentary form of language.
Despite their similarity to modern day humans, heidelbergensis lacked an essential characteristic that makes us who we are. There is no evidence that heidelbergensis ever berried their dead, meaning they lacked the concept of ceremony or the imagination that anything could exist beyond the physical world. However, nature again played an important role in guiding the development of our species, for when then ice age took hold of Europe it separated populations of heidelbergensis from one another.
To the south was a devastating drought that created harsh conditions of survival for hundreds of thousands of years. To the north were glaciers and huge expanses of ice planes. By 400 thousand years ago the era of heidelbergensis was over and Neanderthal dominated the European continent. While Neanderthal was braving the harshest winters ever known to man, to the south heidelbergensis was clinging to life in one of the most severe droughts.
As heidelbergensis faced near extinction, natural selection was place in overdrive. Only the fittest and most inventive members of the population were able to survive, which resulted in an astounding adaptation so far missing in any other species of hominid. It was the development of imagination.
In order to survive in such a harsh climate man needed to develop the foresight to think ahead and the ability to imagine how to use the resources of the environment for continued survival. Imagination was an insurance policy against the problems of the future, and with it a small population of hominid in Africa were able to hold on until, as it always does, the climate changed.