Birds Essay

751 Words 4 Pages
Birds

     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
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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.
     The respiratory system in birds serves to transfer oxygen to the bird’s bloodstream. Unlike mammals, birds do not have sweat glands. So they cannot cool themselves through perspiring. Air sacs throughout the body are connected to the lungs. As the bird breathes, the air sacs help cool the birds organs. The average body temperature of birds is about 106° F.
     Birds do not have any teeth. This means that birds must cut food up with their beaks or swallow it whole. On a bird’s esophagus their is a bag-like swelling called the crop. Bird’s can store food there until there is room in the stomach for it. They can also store food their for their young. In most birds, the stomach is two parts. the first part is

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