The Mesozoic Era
Place the three periods of the Mesozoic Era (Triassic, Jurassic, and Cretaceous) in order and understand that different dinosaurs lived in different periods, not all at the same time
What a learner can do afterwards
- List Triassic, Jurassic, and Cretaceous in the correct chronological order
- Assign at least one well-known dinosaur to the correct period
- Explain that each period lasted millions of years and use dinosaur examples to show that not all dinosaurs lived at the same time
1 · Read
The Mesozoic Era is a long part of Earth's past. Its three periods were Triassic, Jurassic and Cretaceous, in that order. Each lasted millions of years. One followed the next with no gap between them. Different dinosaurs lived at different times.
Stegosaurus, with plates on its back, lived in the Jurassic period. Tyrannosaurus rex lived near the end of the Cretaceous period. Stegosaurus had died out tens of millions of years before T. rex appeared. These two dinosaurs could not have met.
The Cretaceous ended the Mesozoic about 66 million years ago. Non-bird dinosaurs died out then. Some birds survived. Birds are dinosaurs, so dinosaurs are still alive today.
The Mesozoic Era had three periods: Triassic, then Jurassic, then Cretaceous. Different dinosaurs belonged to different periods.
Lesson, questions and flashcards written for this dataset.
Readings and flashcards written for this dataset.
More to read
Placing fossils in time
Fossils include preserved bones, teeth and footprints. Scientists study fossils and the rocks around them to work out when animals lived.
Finding two dinosaur fossils in the same part of the world does not mean the animals lived together. The rocks may come from different times. A Jurassic fossil and a Cretaceous fossil belong to different periods, even if people find them near each other.
Birds before and after the end of the Mesozoic
Birds already existed before the Mesozoic ended. Some survived when it ended about 66 million years ago. Birds did not first appear after that event.
T. rex is extinct, which means no living T. rex remain. Birds are dinosaurs alive today. One kind of dinosaur can be extinct while other kinds are still alive.
Where one period meets the next
When the Triassic ended, the Jurassic began. When the Jurassic ended, the Cretaceous began. Each period lasted millions of years. There was no empty stretch of time between them.
The order tells you that Jurassic time came before Cretaceous time. To find out whether two kinds of dinosaur could have met, you also need to know when each lived. Stegosaurus died out long before T. rex appeared.
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