How humans are we?

Human evolution, the process by which human beings developed on Earth from now-extinct primates.

In our mythology, it is usually one moment when we become “human beings.” Eve planted the fruit of the tree of knowledge and knew good and evil. Prometheus created men from clay and gave them fire.

But in the case of modern tradition, evolution, there is no definite time to create. Instead, human gradually evolved, generation after generation, from earlier generations. 

Like any other complex habit — bird wing, whale fluke, our fingers — our personality evolved step by step over millions of years. Genetic mutations appeared in our DNA, spread across humans, and our ancestors gradually became something similar to us and, eventually, evolved. 

Uncertain Crowds, but still Weapons

Humans are animals, but they are not like other animals. We have complex languages that allow us to speak and convey ideas. We create: We make art, music, tools. Our thoughts allow us to think about the existing world, dream of possible worlds, and reorganize the outside world according to those ideas.

Our social life is a complex network of families, friends, and nations, connected by a sense of responsibility to each other. We also have self-awareness about ourselves and our world: emotions, sapience, consciousness, whatever you call it. 

And yet, the difference between us and other animals, no doubt, is artificial. Animals are more like humans than we can imagine — or even fond of. Virtually every behaviour we once considered to be unique is evident in the animals, even if they are not fully developed.

That is especially true of large monkeys. Chimpanzees, for example, have accessible communication and gestures. They make dirty tools, even weapons, and different groups have different tools — different cultures. Chimpanzees also have a complex social life and interact with one another. 

As Darwin noted in the book The Descent of Man, almost everything about Homo sapiens — emotion, understanding, language, tools, society — exists, in a sense, in some animals. We are different, but we are different than we think. 

And in the past, some species were even more similar to other monkeys — Ardipithecus, Australopithecus, Homo erectus, and Neanderthal. H. sapiens is the only species of human and human-like chimpanzee hominins, which comprise about 20 known species and almost several unknown species. 

The extinction of these homins eliminated all species of living things in our habitat with other monkeys, creating the impression that a vast, unbroken channel separates us from all life on Earth. But the difference would not be so apparent if those species were still extinct. What looks like a bright, sharp dividing line is an artefact of extinction. 

The discovery of these extinct animals also sheds light on that line, and it shows how the distance between other animals and us was crossed — gradually, over a thousand years. 

The Empire of Mankind

Our ancestry was almost separated from chimpanzees 6 million years ago. These first hominins, members of the human race, would not appear to be human, however. For the first few million years, hominin evolution was slow. 

The first significant change was a straight walk, which allowed the homins to move from the forests to the open grassland and forest. But if they walked like us, there is no other indication that the original hominin was more human than monkeys or gorillas. Ardipithecus, the first known hominin, had a slightly smaller brain than a chimp, and there is no evidence that they used the tools. 

One million years later, Australopithecus emerged. Australopithecus possess brain significant in sizw — larger than a chimp, smaller than that of a gorilla. It makes tools far more complex than chimpanzees, using sharp stones to stab animals. 

Then came Homo habilis. For the first time, the size of a hominin brain is larger than that of other monkeys. Tools — stone flakes, hammers, choppers — become even more sophisticated. Then, 2 million years ago, human evolution accelerated for reasons we do not yet understand. 

Great Brain

At this point, H appeared. Erectus. Erectus was taller, taller than we were, and had a larger brain — several times the size of a baboon’s brain, and it made up about two-thirds of us. They made sophisticated tools, such as stone axes.

This was a breakthrough in technology. Hand axes required skill and planning, and you probably needed to be taught how to make one. It was perhaps a tool — used for making other tools, such as spears and digging sticks. Like us, H. Erectus had small teeth. That suggests moving from plant-based foods to eating more meat, perhaps from hunting. 

It is here that our emergence seems fast. The Erectus with a large brain soon gave birth to large brain species. These clever hominins spread throughout Africa and Eurasia, turning into Neanderthals, Denisovans, Homo rhodesiensis, and archaic H. sapiens.

Technology advanced — with the help of sharp spears and stones and firefighters. Items that do not have a clear function, such as jewellery and art, have also emerged within half a million years. 

Homo neanderthalensis, Neanderthals, had a much closer to ours and changed the brain even larger over time until the last Neanderthals had the same ability as modern humans. They may have been thinking of themselves, even talking about themselves, as human beings. 

There is so much about Neanderthals we do not know and never will. But if they were like us in their bones and behaviour, it is reasonable to assume that they may have been like us in other non-record ways — that they sang and danced, that they feared the spirits and worshipped the gods, that they watched the stars, told stories, laughed with friends, and loved their children.

To the extent that the Neanderthals were like us, they must have been capable of performing acts of great kindness and compassion, but also of cruelty, violence, and deception. 

Genetic mixing also required that their hybrid offspring be adopted into their groups — to be treated as human beings fully.