How did dinosaurs evolve?

The ancestor of the dinosaur is the allegodontosaur, the middle Permian, but it is not a dinosaur, the dinosaur appeared in the Triassic, the earliest carnivorous dinosaur: Archaeoptera, the earliest herbivorous dinosaur: Platesaurus, and then to the Jurassic dinosaur species are not many, the climate is humid, to the Cretaceous dinosaurs began to flourish, there are about 700 kinds of dinosaurs, in 65 million years to extinct, some people believe that today's birds are evolved from dinosaurs.

In order to increase the speed of stroke, the cage at that time changed the structure of the body, and then the annual growth accelerated the growth into a free but only one person, your craft 1 3, it people.

1. The ancestors of dinosaurs were lizard-type species, and in the late Permian, there were two different trends in the evolution of organisms, both of which had a profound impact on the history of the earth.

2. Dinosaurs developed into dinosaurs and mammals, and the ancestral lizards had a certain advantage, which evolved into subsequent dinosaurs over time.

3. Elementary evolutionary dinosaurs have appeared in the Carboniferous period, and at the same time appeared the world's earliest reptile Silothian lizards.

4. During the Permian period, dinosaur species gradually diversified, and their shapes began to approach the earliest dinosaurs. The Permian was a relatively arid era, and deserts were common.

5. During the Triassic period, groups of living dinosaurs such as Ichinosaurus and Heterodontosaurus appeared, indicating the complete evolution of the dinosaur race.

Extended material: Dinosaurs are a class of saurimorphs that lived in the Mesograndozoic era, named by British scientist Richard Ashan Owen, meaning "terrifying lizard", which is the most recent common ancestor of modern birds and Diplodocus and all their descendants.

Dinosaurs, with their athletic limbs, long tails, and massive bodies, inhabited mainly woodlands or open areas on lakeshore plains, and they have all become extinct on the earth.

1. Dinosaurs evolved from amphibians.

2. There are two main aspects of evolution. One is the respiratory system and the other is the reproductive system.

3. Although amphibians can live on land, they cannot meet their own oxygen needs due to underdeveloped lungs, and they also need to be assisted by **. Therefore, the ** of amphibians is always wet and cannot live on dry land for a long time. The evolution of reptiles has improved the lung function, relying on the lungs to breathe to fully meet the needs of the body, so the thickening of reptiles and the complete isolation from the outside world.

4. Amphibians and reptiles are oviparous animals, and the growth of eggs and larvae of amphibians is inseparable from water, because the fertilized eggs of amphibians do not have an egg membrane isolated from the outside world, and they must rely on the buoyancy of water to maintain the spherical shape of the eggs, and they must also develop into or clear larvae in the water environment. The larvae are born without lungs and must breathe by their gills.

5. Reptiles have evolved amniotic eggs, which have a hard calcareous egg shell or flexible fibrous egg shell on the outer layer of the egg, and a dense thin egg membrane (i.e., amniotic membrane) inside the egg shell to prevent the egg from mechanical damage, water emission and microbial damage. There are many micropores on the surface of the egg shell to keep the gas from the outside world in front of the change. Once the larvae hatch, the lungs are fully developed.

The evolution of the reproductive system and reproductive mode has allowed reptiles to completely break away from their dependence on the water environment and achieve a full life cycle on land.

6. It is precisely because reptiles have completely gotten rid of their dependence on the water environment that dinosaurs, species that have ruled the earth for more than 100 million years and flourished.