Dinosaurs Ruled The Earth


Dinosaurs evolved from reptiles. They increased in number and species and spread out to the entire Earth during the Mesozoic Era, the geological time frame that spanned 251 to 65 million years ago. The Mesozoic Era was subdivided into three periods: Triassic, Jurassic and Cretaceous.

During the Triassic period (251-200 million years ago), there was only a single supercontinent, called Pangaea, and surrounded by a vast ocean. The middle of the supercontinent was a massive hot desert. Dominant plants; such as cycads, ferns, ginkgophyta or Ginko biloba, and palm-like plants were found in moist areas or near water sources. Animals living at that time were prehistoric fish, turtles, lizards, and large reptiles. The first generation of dinosaurs was considered small, appearing 225 million years ago.

In the Jurassic Period (200-145 million years ago), the supercontinent Pangaea had begun separating into two landmasses: Laurasia to the north and Gondwana to the south, with the ocean in the middle. The wind could blow more humidity from the sea to the heartland. Rain fell in the deserts. Drought gradually disappeared. Forest tracts of various plants expanded. Whereas dinosaurs evolved and increased in number and species, abundant food made them enlarge. For example, Brachiosaurus, a herbivorous Sauropod dinosaur, could weigh up to 70 tons.

In the Cretaceous period (145-65 million years ago), the big continent began to separate and became smaller to look like today’s continents. Wide-leaf and flowering plants started to appear on the Earth. Dinosaurs continued to evolve in numbers, species, size, and shape. For instance, Tyrannosaurus rex a fierce predator, and Triceratops, the Three-Horn Giant, lived in this period.

The exhibition zone4 of the Sirindhorn Museum displays the story of the Mesozoic Age featuring the showcases of model landscape and dinosaurs living in the Triassic, Jurassic and Cretaceous periods. In addition, the skeletons of dinosaurs and other creatures in the same periods; such as, Plesiosaur”s (marine reptiles) and Pterosaurs (flying reptiles) are on display.