In mythology, there is often a bizarre moment when "man" appears. Eve plucked the fruit of the tree of knowledge and gained awareness of good and evil. Prometheus made men out of clay and gave them fire. But in the story of modern origins, there is no decisive moment of creation in the process of evolution. On the contrary, human beings emerged from the early humanoid species generation after generation, gradually.
Just like any other complex evolutionary process— bird wings, whale tails, human fingers, humans evolved step by step over millions of years, DNA mutated and spread to human descendants, our ancestors slowly became what modern humans look like, and finally, humans appeared.
Man is an animal, but unlike other animals. We have complex language that can express and communicate ideas. We are creative and can create art, music and tools. Our imagination allows us to dream of the world that once existed, to think about the world that might still exist, and to reinvent the outside world based on these ideas. Our complex social life is that of family, friends and networks, interconnected and responsible. We also have knowledge of ourselves and the universe: perception, reason, perception, whatever you call it.
However, it can be said that the difference between us and other animals is set by humans. Animals are actually more human-like than we think.
This is especially true for great apes. Chimpanzees, for example, have simple gestures and verbal communication. They make crude tools, even weapons, and different groups have different cultures. Chimpanzees also have complex social lives and cooperate with each other.
As Darwin points out in Descendants of Man, almost every peculiar thing about Homo sapiens—whether it's emotion, cognition, language, tool, or society—exists in some primitive form in other animals. Humans are different from animals, but the differences are not as great as we think.
Historically, some species were more human-like than others—ground apes, australopithecus, Homo erectus, and Neanderthals. Homo sapiens is the only survivor of the once diverse human population and ape population, collectively known as humans. This is a group that includes about 20 known species and possibly dozens of unknown species.
The extinction of other great apes, however, gives the impression of a vast, unbridgeable divide that separates Homo sapiens from the rest of the planet. If these extinct species still exist, this isolation is less pronounced. It's like a bright and sharp dividing line, but it's actually highlighting extinct species.
The discovery of these extinct species bridges that line again and shows how the distance between Homo sapiens and other animals has been gradually widened over thousands of years.
Probably 6 million years ago, Homo sapiens separated from chimpanzees. However, the first humans, members of the Homo sapiens family, hardly resemble modern humans. In the first few million years, the evolution of Homo sapiens was slow.
The first major change was walking upright, which allowed Homo sapiens to walk out of the forest into more open grasslands and shrublands. But even if they walk like modern humans, there is no other indication that the first Homo sapiens were more like modern humans than chimpanzees or gorillas. The brains of the earliest famous homo sapiens populations, Ardipithecus, were slightly smaller than those of chimpanzees, and there is no evidence that they would use tools.
Over the next 1 million years, Australopithecus appeared. Australopithecus's brain is slightly larger, a little larger than chimpanzees, but smaller than those of gorillas. He would make more complex tools than chimpanzees, slaughtering animals with sharp stones.
Then there are the capable people. For the first time, the brains of this population exceeded that of other apes. The tools used, including stone chips, hammers, and cutting utensils, became more complex. Then, about 2 million years ago, human evolution accelerated, for reasons we don't yet understand.
At this point in time, Homo erectus appeared. Homo erectus is taller, more of our stature, and has large brains—several times larger than chimpanzees' brains, and two-thirds the size of modern humans. They made sophisticated tools, such as stone hand axes. This is a major technological advancement. Hand axes require design and manufacturing skills that may be taught and learned. It could be a prototype tool — deriving other tools, such as spears and shovels.
Like us, Homo erectus has small teeth. This suggests that they shifted from a plant-based diet to an increased proportion of meat, possibly from hunting.
It was here that the evolution of Homo sapiens seemed to accelerate. Homo erectus with a greater brain capacity quickly evolved, and brain volume grew even more. These highly intelligent humans were found in Africa and Eurasia and evolved into Neanderthals, Denisovans, Rhodesians, and Homo sapiens. Their tool technology became more advanced— stone-tipped spears and torches appeared. Over the past 500,000 years, they have also manufactured items with unclear functions such as jewelry and artwork.
Some of these species, in terms of bone and DNA, bear striking resemblance to modern humans.
The neanderthal brain volume was close to that of modern humans and continued to expand over time until the last part of the Neanderthal skull was comparable in size to that of modern humans. They may consider themselves human, or even describe themselves as human.
Archaeological records of Neanderthals document their unique human behavior and also imply that they had a mind similar to that of modern humans. Neanderthals were skilled and versatile hunters who harnessed everything from rabbits to rhinos and woolly elephants. They made sophisticated tools, such as throwing sharp spears, jewelry from shells, teeth and eagle claws, and had the art of building caves. Neanderthal ears, like modern humans, adapted to the subtleties of listening to language. We know they will bury the dead and may mourn them.
There's a lot more we don't know about Neanderthals and may never know. But if they were so physically and behaviorally like us, even though they left no records, we could reasonably guess that in many ways they were like us, singing and dancing, fearing ghosts, worshipping gods, wanting to know the secrets of space, like telling stories, laughing with friends, and loving their children.
As long as Neanderthals are like us, they will certainly behave very kindly and compassionately, but there will also be cruelty, violence and deception.
Little is known about other species, such as denisovans and Rhodesians, but from their large brain volumes and skulls, it is reasonable to assume that they are very similar to modern humans.
This is, of course, speculation only. But one detail is that the DNA of Neanderthals, Denisovans, and other Homo sapiens is also present in modern humans. Modern humans met them and had offspring.
It was not impossible for Homo sapiens to capture Neanderthal women, and vice versa. But getting Neanderthal genes into our population requires not only mating, but also raising children, who grow up to raise their own children. It is more likely that these matings are based on voluntary intermarriage. Genetic mixing also requires that mixed-race offspring be accepted into the Homo sapiens community in order to be considered normal humans.
I believe that this phenomenon occurs not only for Neanderthals, but also for other mixed-race human populations, including Denisovans and the little-known African apes. This is not to say that inter-population hybrids are unbiased or completely peaceful. It is conceivable that modern human groups may have been responsible for the extinction of these primitive human groups. However, we must examine the differences between these ethnic groups to find common characteristics.
While modern human populations did survive, hominid groups went extinct, and this went on for a long time. The extinction of Neanderthals, Denisovans and other species has taken hundreds of thousands of years. If neanderthals and Denisovans were really dull, lacking language skills and complex ideas, they would not have been able to resist modern humans for a long time, and they really did.
If they are like modern humans, how can we replace them? This is unclear, meaning that the differences between the two have left no obvious archaeological evidence. The spark of creativity, maybe it's the way it's expressed in language, maybe it's the knack for making tools, maybe it's the ability to work together, that gives us an edge. Whatever the difference, it is only very slight, otherwise modern humans would not have spent so long eliminating these ancient humans.
Until now, I have not answered an important question, arguably the most important one. It's about how humans evolved, but what about humans? How do we study and identify him without defining him?
People tend to think that there are certain qualities that set us fundamentally apart from other animals. For example, most people tend to think that it is okay to sell cattle, cook beef, or eat beef, but not to eat a butcher, which is inhumane. Under social morality, we can tolerate showing chimpanzees and gorillas in cages, but doing so for humans can make people feel uncomfortable. Similarly, we can go buy puppies or kittens, but we can't buy and sell babies.
The rules are different for us and the other. We are born with the view that we occupy the moral and spiritual high ground. We may bury our dead pets, but we don't think that the ghost of a dog will haunt us, nor do we think that a cat is waiting for us in heaven. However, it is difficult to find evidence that such people are fundamentally different from the other.
The word "human nature" means compassion and mutual care, but that can be said to be a mammalian quality, not a human quality. The mother cat loves her kitten, and the dog loves his owner, perhaps more than anyone else has affection for each other. Both whales and elephants have a lifelong family bond. Whales seem to grieve for the dead baby whales, and elephants have been seen wandering around the remains of their dead companions. Emotions and relationships are not unique to humans.
Perhaps it is this awareness that sets humanity apart. But dogs and cats also seem to perceive. Their perception is the same as ours. They knew us very well and knew how to let us feed them or get them out for fun, and even knew we needed company after a bad day. If it's not consciousness, what is it?
We might point out that the complex human brain is different, but is this unique to humans? Broad-nosed dolphins have brains that are a little bigger than ours; elephants have brains three times bigger than ours; killer whales, four times bigger; sperm whales, five times bigger. Everyone's brain volume is also different. It may be that something other than the volume of the brain sets us apart. Perhaps more things are happening in the minds of other animals, including extinct primitive humanoid species, than we might think.
We can define human beings with higher cognitive abilities, such as art, mathematics, music, language. This creates a strange problem that humans vary in the way they do these things. My literary attainments are not as good as Jane·· Austin High, my musical sense is also better than Taylor Swift, I don't have the ability to speak as well as Martin Squibb. Luther · Jin Qiang. In these respects, am my human qualities inferior to theirs?
If we can't define human traits, how can we really say where humans start and where do they end? Or are humans unique? If we can't be sure what makes humans, why should we insist that other species are inherently inferior?
Logically, modern humans are not necessarily the end of human evolution. We are one of many intelligent races. Yes, we won. But imagine if there had been another evolutionary process, different sequences of genetic mutations and historical events, Neanderthal archaeologists were studying our strange skulls and wondering what kind of Homo sapiens we really were.
The nature of evolution means that biological categories are uneven and diverse. Species gradually evolve, from one to the other, and each individual in the species is slightly different, which in turn makes evolutionary changes possible. However, it becomes more difficult to define humans.
Due to natural selection, we are not like other animals, but like them, the ancestors of similar groups are the same. We humans are similar, our ancestors will be mixed with other Homo sapiens ancestors, and the difference is due to evolution and we have inherited the special genes of the population, and even inherited some genes of neanderthals and Denisovans.
Therefore, it is difficult to make a strict classification of organisms, because evolution has caused population characteristics to change continuously, creating diverse species, and diversity within species.
That's why everything is different.
Admittedly, in some ways, the human species is not diverse. Homo sapiens exhibits less genetic diversity than the average bacterial strain, and our bodies change less in shape than sponges, roses, or oaks. But human behavior is varied. We are hunters, farmers, mathematicians, soldiers, explorers, carpenters, criminals, artists. There are many different ways of being human, there are many different human environments, and everyone must determine what it means to be human. Ironically, it is this indefinability that is the greatest characteristic of human beings.
Author: Nicolas Longridge Senior Lecturer in Paleontology and Evolutionary Biology, University of Bath, UK.