Question

essay on variety of birds

Answer 1

Birds are some of the most amazing animals on earth. Most have the 
ability to fly. Some use ground travel. Some use claws, others use only their 
beaks. Birds come in many varieties of colors and sizes. 
     Birds are warm-blooded, egg-laying creatures from the aves class. Along 
with the obvious feathers and wings, birds have other adaptations for flying 
such as a wide keel on the sternum, with large wing muscles attached, air spaces 
and sacs throughout the body and bones, to decrease their weight, and they have 
various bone fusions and reductions to strengthen and streamline their body. 
     There are more than 8700 species of birds. Their habitats range from icy 
shores of Antarctica to the hottest parts of the tropics and from mountains, 
deserts, plains, and facts to open oceans and deeply urbanized areas. 
     The sizes of birds range from the tiny bee hummingbird, which has a 
total length of two and a half inches, to the albatross, which has a wing span 
of eleven and a half feet. The largest bird is a bird that cannot fly, the 
ostrich. Ostriches can stand almost eight feet high and can weigh near 350 
pounds. Other extinct birds have been measured to stand over ten feet high. 
     The evolution of birds is still being argued. Most people believe that 
birds evolved from reptiles. Because of birds mainly delicate bones, few fossils 
have been left behind for scientists to study. The earliest bird fossils come 
from archaeopteryx. The fossils that have been discovered from archaeopteryx 
include six partial skeletons and one single feather. Archaeopteryx , unlike 
modern birds, had teeth, a reptile like tail, and three claws on each wings. 
Scientists think it could fly, but only weakly. 
     Approximately 85 species and 50 sub species have become extinct in the 
last 300 years. Over half of them occurred in the 1800’s. Another thirty percent 
occurred in the 1900’s. Over ninety percent of these extinction’s were island 
forms, which are particularly vulnerable to human interference. Destruction of 
habitat is the biggest cause of extinction. Other causes are the introduction of 
predacious animals, and disease plays it’s part too....