Written by: Samyam Shrestha - 2022012, Grade XI
Posted on: 25 March, 2021
Dinosaurs were separated in accordance with geologic time. The age of dinosaurs started from the Triassic Period ( about 230 million years ago ) followed by Jurassic Period (about 201.3 million years ago - 145 million years ago ) and last came the Cretaceous Period (about 145.5 million years ago - 66 million years ago ). Many different species of dinosaurs lived during these periods. For example: During the Triassic period there was a dinosaur named Saltopus, those were extinct in the Jurassic period and the same goes for other dinosaurs. Their species went extinct during their time period. As per the research shown, there used to be a supercontinent called Pangea at the beginning of the Triassic period. But due to some incident, the continent broke apart, and the dinosaurs scattered across the globe. During the process, many species of dinosaurs evolved in their own geographical region.
Triassic Period :
The Triassic period started and ended with a huge disaster wiping out almost 90% of the species. The remaining species repopulated the earth and evolved during the process. Ocean was filled with different species of living beings and air was fully dominated by Pterosaurs and other flying reptiles. Slowly dinosaurs started to evolve. Some dinosaurs that used to live in the Triassic period are Coelophysis, Pterosaurs, Plesiosaurs, etc.
Jurassic Period :
After the disaster, the Jurassic period started. Supercontinent Pangea was divided during this period. Mountains, hills, plain land started to form with high amounts of trees and plants. Dinosaurs during this period were huge. The earliest known bird, Archaeopteryx, also originated during this period. Brachiosaurus stood 85 feet tall and weighed 80 ton. The massive herbivores were equally matched with the biggest carnivores.
Cretaceous Period:
During this period, continents were moving in the same position as they are in the present day. Due to it, oceans expanded and caused certain changes in climatic conditions of the continents. New dinosaurs evolved who dominated the continents. Spinosaurus dominated the southern part whereas Tyrannosaurus rex dominated the northern part. Mammals evolved during this period. The ocean was dominated by large predators like the Megalodon, Mosasaurus. But, at the end of the time period, dinosaurs were wiped out by a huge natural disaster.
Dinosaurus derives from greek “deinos” which means “Terrible” or “Fearfully great” and “sauros” means “Lizard” or “Reptile”. They dominated the Mesozoic era and went extinct during the same era.
