          |
DIFFERENT PERIODS When we talk about dinosaurs, we can name 3 different periods: 1- Triassic 2- Jurassic 3- Cretaceous The Triassic period started 250 million years ago. Then, there weren't the continents we know today. There was one big super-continent called Pangaea. The climate was mild with only a few weather changes and there weren't any polar ice caps. On the Earth there were mainly mammal-like reptiles, turtles and sea reptiles. By the end of the Triassic period the first dinosaurs appeared and spread through all Pangaea. The Jurassic period began 208 million years ago. It was in the Jurassic period that the super-continent Pangaea started to separate and form the lands of "Laurasia" in the North, and "Gondwana" in the South. The climate became wetter and rainier. Thick plants such as ferns, ginkgoes, and conifers covered most of the Earth. New types of dinosaurs appeared which ate mainly plants. One of them was the "Sauropods". It was so big that it is consider the biggest animal that ever lived on the Earth. They ate one ton of plants every day. Can you imagine how big his stomach must have been?.. Although the dinosaurs were the dominant animal of this period, there were other animals, and insects as well as the first birds. The Cretaceous period started 146 million years ago. By the end of this period, the Earth subdivided in more parts until the continents that we know today were formed. The first plants with flowers appeared. The pollen of these flowers was the reason for the appearance of more insects and other mammal and bird species. The Earth was covered with herbs, bushes and deciduous trees. During this period, the climate was generally warm and there were bigger differences between the seasons. |
  |