By Land, Sea, and Air

As ammonoids filled the seas, a new kind of animal evolved on land—reptiles. Reptiles were better adapted to land than amphibians because they could live their entire lives without returning to the water. Reptiles had tough scaly skin that could survive the sun’s rays better than the moist skin of amphibians. Even more important was the evolution of eggs with watertight shells. Reptile eggs had a supply of food and water inside and tiny breathing holes so air could reach the baby. Because these eggs could be laid almost anywhere, reptiles evolved quickly over the next 100 million years.

Some reptiles were a lot like mammals (see pages 24-25). Others, called pterosaurs, developed long wings and were able to fly. Still other reptiles, including plesiosaurs and fish-like ichthyosaurs, were adapted to life in the seas! The most famous land reptiles of this time, though, were dinosaurs. These creatures included both meat eaters (carnivores like T. rex) and plant eaters (herbivores like Diplodocus). They could be as small as a chicken or the length of three buses, and they walked on either two legs or four legs.

The time period from 247 to 65 million years ago is called the “Age of Reptiles” because there were so many reptile species living in all kinds of habitats at that time.

Below is a scene from the Age of Reptiles that shows five different reptiles. If you were each of the reptiles below, what would you be looking at? Write the letter of each reptile on the short line by the scene it sees from its position on land, in the sea, or in the air. (There is an extra picture to help fool you.).

Bonus: Now look at the reptiles in the big picture again. Decide which is which, match their letters with your letters by the circles, and write each animal’s name on the correct line below the circles. (The descriptions in the text will help you. See the animals’ names in heavy type.)