Geologic Ages
Mesozoic Era

Topics covered in this section:

Introduction
Mesozoic Era

Introduction

The reptiles, survivors of the mass extinction during the Paleozoic Era, gave birth to the age of dinosaurs. But they, too, suffered a mass extinction near the end of the Mesozoic Era, some 65 million years ago when some seventy percent of all organisms were wiped out.

Mesozoic Era

Triassic Period

During the Triassic Period, 240 million to 205 million years ago, small dinosaurs, ichthyosaurs, and plesiosaurs appeared. The planet also saw the appearance of the first true mammals.

Jurassic Period

The Jurassic Period, 205 million to 138 million years ago, heralded the appearance of huge dinosaurs and flying pterosaurs. It was a time when the Earth witnessed the emergence of the oldest known birds.

This was the period made popular by Hollywood movies. And, of course, our Hollywood favorite, Tyrannosaurus Rex, snapped its huge jaws around less fortunate prey. Tyrannosaurus Rex's reputation is currently the subject of a heated scientific debate. Was this king of lizards a predator or a scavenger? I won't add my thoughts to the debate.

Cretaceous Period

Again the planet faced the near extinction of all life forms, this time during the Cretaceous Period, 138 million to 65 million years ago.

Following a period of global warming, which encouraged the spread of the dinosaurs' domain, a sudden mass extinction, perhaps due to an asteroid impact, spelled doom for the dinosaurs and other life forms. Some 70 percent of all organisms were wiped out.

Go Elsewhere

At this point, you have a couple of options:

Return to the History Department to choose another timeframe.
Rewind to the previous section, the Introduction Section.
Fast forward to the next section timeframe, the Stone Age Section.
Select a specific section topic (shown in preferred reading order):
- Precambrian Era
- Paleozoic Era
- Mesozoic Era You are here!
- Cenozoic Era
- Pleistocene Epoch