Dinosaur Timeline: Lesson for Kids

Instructor: Mary Beth Burns

Mary Beth has taught 1st, 4th and 5th grade and has a specialist degree in Educational Leadership. She is currently an assistant principal.

While dinosaurs are no longer around, they certainly went through quite the journey when they roamed the earth! Come and learn about the three periods in the dinosaur timeline, as well as how dinosaurs still live on today.

The Beginning

Did you know that for the first 3,500 million years of Earth's existence the only living things were so small they would only have been able to be seen with a microscope? After that, different animals began to evolve, and eventually, some of the most amazing creatures appeared: the dinosaurs.

Dinosaurs, which were mammal-like reptiles, first began to appear during the Triassic period, which began around 250 million years ago. Our planet looked very different during this time. It was much warmer than it is now, and all of the continents were connected into one big supercontinent land mass called Pangea. Earth was just recovering from a natural disaster that killed more than half of the species, so there wasn't too much going on.

The dinosaurs that roamed the earth during the Triassic period were much smaller than many of the dinosaurs we talk about today. They were certainly no match for a Tyrannosaurus Rex! One of the first dinosaurs of the Triassic period was the Coelophysis, which is thought to have been less than 10 feet tall and weighed less than 100 pounds. A few species of small reptiles that lived in the ocean began to emerge as well.

Dinosaurs you might have seen during the Triassic period
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The Middle

After the Triassic period ended, the Jurassic period began, around 210 million years ago. During this time, dinosaurs grew to be bigger than ever before. For example, the Brachiosaurus grew to be around 50 feet tall and 80 feet long. The Stegosaurus weighed close to 3,500 pounds, which is about the same weight as a car. Reptiles in the ocean grew, too, some of them were as big as whales! Not only did dinosaurs grow in size during the Jurassic period, this was also when dinosaur-like flying reptiles came around.

The End

The Cretaceous period was the most recent and final time period of the dinosaurs. A few of the most famous dinosaurs to evolve during the Cretaceous period were the Tyrannosaurus Rex, the Velociraptor and the Triceratops. During this time, more and more species of dinosaurs began to appear. In fact, this is when the dinosaur population was at its most diverse state.

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