Were there dinosaurs in the world 100 million years ago?

There were dinosaurs in the world 100 million years ago.

Dinosaurs are diverse and dominant terrestrial vertebrates in Mesozoic. The word "dinosaur" is a Japanese biologist's translation of English Dinosauria, that is, "scary lizard", rather than "dragon" in China's traditional culture. Dinosaurs once ruled the global terrestrial ecosystem for more than 65.438+0.6 billion years. Dinosaurs first appeared in the Triassic period 230 million years ago and died out in the late Cretaceous period about 65 million years ago.

Dinosaurs lived on the earth for 65.438+0.6 billion years. In such a long time, many changes have taken place in the environment of the earth. Pangu continent, which was originally connected as a whole, gradually drifted and split into familiar forms. After these earth plates drifted around the world, the climate environment changed because the light was no longer uniform and the heat conduction was blocked by the ocean. In the early dinosaur era, the dwarf shrubs composed of ferns were the main vegetation on the earth. Plate drift, coupled with climate change, has caused great changes in plant species on the earth. However, because these changes took place gradually over a long period of time, the animals growing in them can still adapt well. However, due to the intensification of crustal movement and frequent geological activities in the middle period of dinosaur era, the land climate changed. In the late dinosaur era, because the climate became dry and cold, deserts appeared on the earth.