Dinosaurs - Colorful Creatures? 22259
The word dinosaur might make you picture reptiles today, so they would blend into their environment.
Dinosaurs - The Name Game 69291p
Most dinosaur names aren't as easy to say as Triceratops means 'three-horned face'. Other times they are named after the place they were discovered like Arctosaurus found near the Arctic Circle. Yaleosaurus was named for Yale University. Some dinosaurs are even named for people. Palaeontologist Orthneil C. Marsh had Marshosaurus named after him. About 700 species have been named. That's a tough list to memorize.
Procompsognathus Dinosaur
Dinosaurs - Beginning to End 361f72
The years dinos roamed Earth are divided into three periods, which are called the Mesozoic Era.
- Triassic Period (225 to 193 million years ago) - During the Triassic Period, dinosaur ancestors were evolving. In the Late Triassic, the world saw the first true dinosaurs.
- Jurassic Period (193 to 136 million years ago) - In the Jurassic Period, the number of dinosaurs grew.
- Cretaceous Period (136 to 65 million years ago) - By the Cretaceous Period, many different types of dinosaurs had evolved.
Dinosaurs - Bon Voyage 5lo20
Scientist know dinosaurs were no longer around 65 millions years ago. They can tell how old layers of rock are and no dinosaur bones have been found in rock less than 65 million years old. So how did they all die out? There are two main theories about this:
- Gradualistic theories say the dinosaurs were in a slow decline and that gradual changes in the environment caused their extinction.
- Catastrophic theories say the dinosaurs disappeared abruptly due to some world-wide catastrophe. Perhaps a giant meteor crashed into Earth, covering the world in dust and hiding the warmth from the Sun.
Dinosaur Fun Facts 6p1r5s
- Longest Dinosaur: Seismosaurus - 150 feet long
- Heaviest Dinosaur: Argentinasaurus - 220, 000 pounds
- Longest Dino Name: Micropachycephalosaurus - 23 letters
Argentinosaurus Dinosaur
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