Question

Which of the following is an era to which the Jurassic period belongs?
(a) Paleozoic
(b) Mesozoic
(c) Cenozoic
(d) Proterozoic

Answer 1

Hint: This is the era when dinosaurs ruled the earth and the end is marked by the mass extinction of a number of species. This era lasted for 251 million to 65.5 million years ago, also known as the ‘age of reptiles’. In this era, the earth's surface changed dramatically which resulted in Pangaea breaking into smaller continents and climates were warm and humid.

Complete answer:
The Mesozoic Era is subdivided into three parts: Triassic, Jurassic and Cretaceous periods. During this period dinosaurs were the dominant terrestrial vertebrates. The most popular of all dinosaur species is Tyrannosaurus rex, lived during the Late Cretaceous period. This was the time of tectonic, climate and evolutionary activity. The climate was extremely warm throughout the Jurassic period which played an important role in the evolution and diversification of the new basis of modern life.

Additional Information:
- In the Mesozoic era ankylosaurs, cretaceous and hadrosaurs were common during the final period of the dinosaur region.
- The earliest angiosperm or flowering plant appeared during the Cretaceous period.
- Jurassic was about 65 million years long and ended 35 million years ago. This is the second phase of the Mesozoic era.
- Cretaceous period was marked by a peak in dinosaur diversity and rise of mammals where the period ended with a massive meteorite.
- At the beginning of the Jurassic period the continents were still together forming Pangaea but soon they were starting to drift apart.
- During the Jurassic period the climate was very hot and dry which made new groups of dinosaurs appear.
- The Jurassic formation was first known in the Jura Mountain between France and Switzerland thus, from this Jurassic name is derived.
- The Mesozoic era was marked by the lizards, turtles, crocodiles, snakes and a variety of dinosaurs that flourished.
- The first corals formed in this era and oceans were home to ammonites, molluscs and sea urchins whereas the ground was covered by moss, liverworts and ferns with conifers, ginkgoes and palm-like cycads.
- The Mesozoic period ended about 66 million years ago with major mass extinction.

Therefore, the correct answer is, (b) ‘Mesozoic.’

Note:
- The Jurassic period of the Mesozoic era was divided into three parts:
Early Jurassic - Lias
Middle Jurassic - Dogger
Late Jurassic - Mlm
- In the Jurassic period was marked by Himalayan deposition where the rock that would ultimately become the highest point on the earth were deposited on the earth in the Triassic and Jurassic periods as limestones, dolomite and shales.