Half-human, half ape. A new species discovered in South Africa adds a mysterious new element to our evolutionary history.
Modern palaeontological and archaeological discoveries are constantly changing and expanding that which we learn in school about the evolutionary history of humans. What we have always assumed to be a linear development we now know to be a fragmented evolutionary process. Nowadays, how would you construct the evolution of the ape-man?
First of all it must be said that even the common "belief" that we evolved from apes is not scientifically correct. We have a common ancestor with apes such as chimpanzees, gorillas, orangutans, gibbons etc., which now live and share this earth with us. This ancestor existed around six million years ago and probably had aspects more similar to that of apes today rather than humans today. But no human “evolved from monkeys” as is commonly said. With regard to the evolutionary process which resulted in today’s humans, we know now that this process is somewhat similar to that which has led to the evolution of all other life forms. That is to say that from this common ancestor both apes and humans have followed a path dotted with various intermediate stages (now extinct fossils) which can be likened to branches of a tree emanating from the main trunk. Man is just one these branches which evolved from a common ancestor, along with the great apes.
What makes the discovery of this new species of the Homo naledi so important in understanding our development from an evolutionary point of view? What are some features which characterise this hominid?
There are essentially two things that make Homo naledi so important and which set it apart from other findings made before now. The first is that we previously believed that the evolution of the genus Homo (to which we, Homo sapiens, belong) had resulted in the simultaneous development of a large brain, modern eating habits, the ability to walk on the ground for long distances and the loss of the the ability to climb trees - as if it were a package. Contrary to this belief, Homo naledi shows us that it is possible to exist in the Homo genus with a very small brain (450-550 centimetres cubed as opposed to 1300) whilst also retaining the ability to climb trees - as is evident from anatomical aspects such as the shape of the shoulders and the fingers of the curved hands. The second thing concerns the circumstances which led to the accumulation of so many fossils (1550) in the Dinaledi Room. The best assumption that we can make at the moment is that Homo naledi intentionally deposed their dead in that cave. I don’t mean this with reference to a funeral in the modern sense of the word, but rather to the act of taking the dead away from the living. This was perhaps done to protect the living from attacks by predators which would have been attracted by the smell of decaying bodies. Anyway, this is complex behaviour which we didn’t believe possible of a hominid like Homo naledi, with a brain of such a small size.
Over the course of evolution, our species has had a big impact on the planet which has resulted in radical environmental changes and consequently the extinction of certain animal and plant species. How can we learn from these experiences to help us prevent the destruction of a future world?
We can be distinguished from all other animal species by the complexity of our brains which therefore results in the ability to behave in a complex way. This behaviour has anatomically allowed modern humans to colonise the world, beginning around 50,000 years ago. It is a characteristic of our species to modify an environment to better suit it to our “needs”. This has led to all of the advantages and disadvantages that come with being Homo sapiens. Therefore, the study of the final stages of human evolution plays a strong role in understanding the impact which our culture and our needs have had on the natural world around us. It can certainly be used to further understand what we need to do in the future to safeguard our planet. To understand better how past populations managed to maintain the delicate balance with the environment in which they lived is one of the most important contributions which anthropology can give in an effort to ensure a sustainable future for us and for what is left of our planet.
3D printing a Homo naledi cranium. Photo: John Hawks CC-BY-NC-ND