What is the evolutionary history of dinosaurs?

Dinosaurs developed about 230 million years ago and divided from their cousins ​​Archosaurs in an early trias, 21 million years after the catastrophic extinction of Permia, which greased most of life on Earth. Like other archosaurs, dinosaurs are characterized by socket-teeth, which makes them less likely to be relaxed during feeding, distinctive holes in the skull and a special comb for muscle connection to the femur.

Before the extinction of Permian-Triassic, archosaurs were a relatively unclear group of reptiles. In the late Permia, the soil of therapy, ancient mammal relatives, dominated. Most of the therapy did not survive the extinction of the End-Permian very well or the arid world that followed it. This left several main ecological niches wide open, which archosaurs began to use. Many scientists believe that the reason for the rise of archosaurs and dinosaurs has been related to better strategies to deal with the arid environment. For example, archosaurs can release uric acid - a side forDukt metabolism found in the urine - more like a paste rather than a liquid and maintaining water. The advantage would also lack glandular leather.

What is considered to be the normal predecessor of all dinosaurs, eoraca , a 1 -meter -high bipedal predator, developed about 230 million years ago. Suddenly it was assumed that the dinosaurs were a paraphyletic group, a group that consisted of a common ancestor and all its offspring, but most scientists have since come to the conclusion that all dinosaurs have descended from a common ancestor. Before Carnian, about 215 million years ago, dinosaurs were relatively rare and represented only 1-2% of land fauna. On the Karn border, however, many therapies and other archosaurs who survived finally extinct in Permia, finally disappeared and for dinosaurs remained generally open.

To conCi trias began the age of dinosaurs. Two main types of dinosaurs, therapy and sauropods, so diversified enough to occupy most of the main ecological niches. Over time, they have become less primitive, with some groups such as sauropods, gradually increased until they weighed more than the blue whale today. During most mesozoics, each animal was greater than a meter of dinosaur of some kind.