Aves

Characteristics

Birds are the only living descendants of the dinosaurs and are most closely related to theropod dinosaurs. They evolved from theropod dinosaurs during the Jurassic period, and by the end of the Cretaceous period, most modern bird orders had emerged. The earliest known bird is Archaeopteryx, which lived about 150 million years ago. The first birds were likely small, feathered dinosaurs that lived in trees and used their feathers for insulation and gliding.

Birds have a number of adaptations that allow them to fly, including wings, lightweight bones, and a streamlined body. However, not all birds can fly. Flightless birds, such as penguins, ostriches, and kiwis, have evolved adaptations for other forms of locomotion, such as swimming, running, or digging.

Environments

Birds can be found in a wide variety of environments, including forests, grasslands, deserts, mountains, and oceans. They play an important role in their ecosystems, acting as pollinators, seed dispersers, and predators. Birds are also important indicators of environmental health, as they are sensitive to changes in their habitat and food sources.

References

For further information about Aves, please visit these reliable sources:

• Wikipedia's Page on Birds
• The Audubon Society
• Cornell Lab of Ornithology