What is the Phanerozoic eon?

What is the Mesozoic era? When?

What are dinosaurs?

How do we classify them?

The Phanerozoic Eon is the current geologic eon in the geologic time scale, and the one during which abundant animal and plant life has existed. covers 541 million years to the present.

The Mesozoic Era is the age of the dinosaurs and lasted almost 180 million years from approximately 250 to 65 million years ago. This era includes 3 well known periods called the Triassic, Jurassic, and Cretaceous periods.

Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago.

Dinosaurs are divided into two orders based on their hip (pelvic) structure:

the "Lizard-Hipped" or Saurischian dinosaurs

the "Bird-Hipped" or Ornithischian dinosaurs.