U Forests And Grasslands

The Early Tertiary was a hot period when much of the world was covered by tropical forest. But by the Late Tertiary, about 10 million years ago, the climate had cooled and the forests were giving way to open grasslands.

Heavy tail balances the kangaroo when it is bounding across the plains on its hind legs

U ATHLETiC GRAZERS

The open plains that appeared in the Late Tertiary were colonized by mammals that were able to eat grass. Since they had nowhere to hide, many developed ways of moving fast to escape danger, such as the hopping technique of a modern kangaroo.

Streamlined body and powerful muscles enable a dolphin to swim like a shark

. Long fLIGHT fEATHERS

extend the parrot's forelimbs into superbly efficient wings

Like the mammals, birds evolved many forms during the post-dinosaur era. Their feathers and lightweight skeletons made them ideally equipped for flight, and their mastery of the air has enabled them to exploit a wide range of habitats. Some, like this parrot, are among the most colorful of all animals.

Heavy tail balances the kangaroo when it is bounding across the plains on its hind legs

U ATHLETiC GRAZERS

Streamlined body and powerful muscles enable a dolphin to swim like a shark

. Long fLIGHT fEATHERS

extend the parrot's forelimbs into superbly efficient wings

U SLEEK SUCCESS

The mammals have diversified to fill every habitat left vacant by the extinct dinosaurs, pterosaurs, and marine reptiles. Most live on land, but bats have taken to the air, and whales and dolphins spend their entire lives at sea. These dolphins may look like fish, but in many ways they are the modern counterparts of the Jurassic Icthyosaurus.

0 0

Post a comment