About 225 Million years, a new group of reptiles appeared on earth. Like all reptiles, They had waterproof,scaly skin and young that hatched from eggs.
For the next 160 million years they ruled the earth, before finally becoming extinct.
For the next 160 million years they ruled the earth, before finally becoming extinct.
Land legs:
Dinosaurs were land animals they could not swim or fly, All dinosaurs had four limbs, but many, such as Tyrannosaurus rex, walked only on their two back legs, leaving the front legs free for other tasks.
Dinosaur Divisions :
Dinosaurs are divided into two groups based on the shape of their hips:sauruschians (lizard-hipped) and ornithiscians (bird-hipped). Saurischians had one lower hipbone pointing downward and forward,and the other downward and backward. Ornithischians had their two lower hipbone pointing downward and backward.
Time Lines:
Dinosaurs Lived through three periods in Earth's history -- Triassic.Jurassic and cretaceous. Different species of dinosaur lived and died throughout these periods.Each species may have survived for only 2-3 million years.
Living reptiles:
Modern reptiles,such as this iguana, have many features in common with dinosaurs, such as scaly skin and sharp claws. But many scientists believe that birds, rather than modern reptiles, are the closest living relatives of the dinosaurs.
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