How did man evolve?

Tetrabibians evolved into amphibians.

Evolution from fish to man: The longer scientists look for it, the more they realize that an important fossil is missing, which becomes a major challenge to the entire theory of evolution. And the story of how we got our feet becomes a search for the "ultimate lost fossil".

As early as 150 years ago, this continuous search began, and the result was a simple observation: a large group of seemingly unrelated animals were in fact related – they all had limbs, so they were collectively called tetrapods. Man is a tetraped because man has two hands, two legs, cats, dogs, horses are obviously also quadrupeds, in fact, all mammals are tetrapeds.

Birds, frogs, lizards, and even snakes without legs, and whales that appear to have no legs, are also tetrapods. All tetrapods, no matter how different they may seem, have essentially the same structure beneath their epidermis. Scientists are also puzzled by this fact.

Dinosaurs have backbones, humans have backbones, and quadrupeds have backbones; There are also pelvic bones attached to the spine to support body weight; They also have a thoracic cage that protects the heart and lungs. Quadrupeds breathe air through their nostrils, and their limbs are made up of a single bone at the top and a pair of bones extending to the hand or foot below, and there never appear to be more than five fingers or toes. This was true not only of dinosaurs and humans, but also of whales, which still have five fingers under their flippers.

This similarity has led scientists to believe that all tetrapods must have descended from a common ancestor. To prove this, they believe that only two fossils are needed. First of all, it is necessary to be the first quadruped to walk on land, and it is necessary to use 4 legs, and each foot has 5 toes; Secondly, the fish that needed the first to grow legs, and it was this fish that became the first quadrupeds to land and walk.

Find fossils of these two animals, compare them, and find out the difference between them, and you can see why fish have legs. One important clue leading scientists is that this evolution probably occurred 400 million years ago in the Devonian period. However, the Devonian period is so far away that even the stones of that era are hard to find today, let alone fossils.

However, scientists know that before the Devonian, there were no walking animals on land, and after the Devonian, the land was full of walking animals, so the evolution of the limbs must have happened at that time. Textbooks say that the Devonian was a time of unbearable heat, with few organisms surviving on land, not even plants. The land was a barren, empty wilderness, lifeless.

This means that the vast majority of life on Earth at that time could only stay in water. This is the age of fish, and the fossil of one of the fishes, the first fish to grow legs, is the second fossil that scientists need to find. It can be said that man is also a fish, to be precise, evolved from fish.

Human beings are from simple to complex, from marine to terrestrial, natural selection, survival of the fittest, after a long time, human beings have evolved!

Human ancestors may have evolved from archaea in the first place.