The story of human evolution began with the extinction of the dinosaurs. 65 million years ago, an asteroid struck the Earth, causing a global prolonged climate cooling, most plants disappeared due to the inability to photosynthesize, plant-eating dinosaurs also died because they did not have food, and carnivorous dinosaurs also gradually perished because they had no food source, and only small animals and a small number of plants survived.
Dinosaur extinction
In this impact event, the dinosaurs that dominated the Earth's terrestrial ecosystem for 140 million years went extinct, and mammals rose to become the dominant class, and in a relatively short period of time, there was a rich and diverse evolutionary boom. Over the next 10 million years, three to five thousand species of mammals appeared on Earth, including the earliest whales, bats, rodents, and monkey primates that were crucial to the human story—our earliest ancestors.
Then these prehistoric primates soon underwent many changes, the first major development occurred sixty million years ago, when the evolutionary line was divided into "wet-nosed primates" and "dry-nosed primates", which was a critical moment of slow development towards Homo sapiens, and it was not until twenty million years ago that another major development occurred. The arrival of the first ape was known as the proto-Consul ape (scientific name Proconsul).
Fossil of the original Consur ape
Although the proto-Consur ape still behaved much like a monkey, it had begun to take on more and more human-like physical features that today, such as their lack of tails.
And our first major step from ape to human evolution was with the evolution of the ape, the first true bipedal. Developed a breakthrough ability to walk on two legs, as well as having big, interchangeable toes, small cut teeth, and a brain size very similar to that of an ape.
Ground apes
From here, it made great strides in its evolutionary timeline, 4 million years ago– the first Australopithecus evolved. Australopithecus retained the characteristics of apes, including long arms and short legs, but they became more human, largely thanks to a change, with the large toes of the pair that existed in early species now moving forward. This meant that they were more accustomed to walking reliably, freeing up their hands and using the earliest known stone tools.
Australopithecus flourished about 2 million years ago, eventually giving rise to the "genus Human", scientific name HOMO, where human history really began. The first member of the genus Isaac. Colloquially known as "Homo habilis" (scientific name), the most striking aspect of human development is its ever-expanding range of tools. 1.9 million years ago, Homonyny evolved a new branch, Homo erectus, which is the most important step towards modern man!
Homo erectus was the first person to have a very similar proportion to modern humans, and compared to us, Homo erectus had relatively long legs and shorter arms, which allowed them to fully adapt to living on the ground (rather than in trees), which also led to Homo erectus becoming the first group to spread throughout Europe, Asia and Africa.
Between 1.9 million and 100,000 years ago, new members of the genus began to emerge on the world map due to homo erectus migration patterns. As each new species evolved to adapt to different environments, these different groups of humans began to differentiate and intersect at different historical points, forming a complex network of evolutionary lines.
This makes it difficult to speculate from which line of evolution did we modern humans evolve after Homo erectus, and we may have evolved directly from Homo erectus, or from one of several species that branched before or after it. But the only thing we can be sure of is that human evolution has never stopped.
Although most people think that we modern humans are the ultimate agents of human evolution, in fact, human evolution is still continuing, for example, the gradual disappearance of wisdom teeth, and our ancestors had a stronger and larger jaw than ours, which helped them chew hard roots, nuts and leaves. What kind of food needs to be chewed prompts humans to evolve corresponding teeth.
The disappearance of wisdom teeth
Wisdom teeth are the third largest molar (also known as the third molar) and are used to chew foods such as the bark of coarse-eaten fiber tree roots that help the human digestive system. But with the progress of human beings, food has become more and more refined, humans have gradually degenerated what they do not need, the jaw has become smaller, and there is almost no room for wisdom teeth to grow on the jawbone, and the upper jaw has no bite to bite. Like the appendix, wisdom teeth become degenerate organs.
Or, in the past 20,000 years, the average brain capacity of the human brain has shrunk from 1500 cubic centimeters to 1350 cubic centimeters, which is equivalent to reducing the volume of a tennis ball. But that doesn't mean we're stupid, on the contrary, the shrinking brain capacity allows it to handle everything more efficiently, just like the computer processors we see today.
In this regard, Robert Foley, professor of human evolution at the University of Cambridge, said: "From an evolutionary point of view, human change is a continuous and gradual process. We humans are not a fixed entity, it is more like a piece of putty, and its shape changes at any time. ”