What is the oldest fish on earth?

About 300 million years ago, a strange fish fossil, the total fin fish, was found in stratigraphic fossils. The total fin fish has two characteristics: first, its pectoral fins and ventral fins are arranged in the same way as the limbs of modern frogs. This powerful fin is convenient for supporting and moving the body on land; Second, the total fin fish can breathe air directly with the swim bladder.

More than 300 million years ago, the climate was warm, and some areas were not suitable for fish to live in strange environments because of plant rot and lack of oxygen in the water. Thousands of fish died alive during the drought. The drought forced the big fish to climb from one pond to another. The general manager who wants to find water may find that the land of the world is so beautiful!

After Euglena landed and took root, the first huge terrestrial plants grew slowly, forming a large swamp forest. This strange world is very attractive to finfish who are not good at swimming. They finally stayed in the land where they breathed fresh air. There is no harm to them if they have food, so it has been handed down from generation to generation. Thoracic Shao and abdominal Shao become limbs, gills degenerate, swim bladder becomes lungs, and finally a new group-amphibians is formed.

The ancestor of modern amphibians is earthworm. The largest amphibian in the world is the giant salamander, a specialty of China. The most amphibians are frogs and toads, and they have been living happily until now.