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When you have completed this page, go to the Birds Quiz.
Birds are a class of the chordates or vertebrate phylum. They are similar to other chordates in that they have a backbone. They are unique in the fact that they are covered with feathers and fly. There are four types of feathers for birds:
There are about 9000 species of birds, with 24 orders and 146 families. Scientists believe that birds evolved from reptiles and dinosaurs.
Birds are found throughout the world, from the tropics to polar regions. One unique characteristic of many birds is their tendency to migrate. This means that the birds move from colder to warmer areas as the winter approaches.
Birds can be both helpful and harmful to man. They are helpful as they frequently eat harmful insects. They provide food for man. They are pets and can be very decorative. They are harmful when they eat crops and kill animals.
The study of birds is ornithology.
Click on the links below to go to pages with specific birds' pictures.
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System
Type
|
Birds
System
|
| Muscular-Skeletal | A bird has an internal skeleton with two pairs of limbs attached to the main body with two legs and two wings. Their bones are full of holes and are very light to allow them to fly. Their bodies are also streamlined for flight. They have a wide range of feet, depending on where they live and what they eat. |
| Digestion | A bird eats a great deal. They mainly eat insects and seeds, although some eat fruits and other animals. They take in water through their beaks and tip their heads back to swallow. Beaks are in a variety of sizes and shapes, depending on the bird's diet. A bird has a mouth, esophagus, stomach, crop, gizzard,intestines, liver and pancreas. |
| Nervous | A bird has relatively large eyes that allow it to judge distance well and an excellent sense of hearing. Their tongues are used to feel things. They have beautiful voices. They have a brain and spinal cord. |
| Circulation | A bird is warm-blooded. The bird has an excellent heart that pumps vigorously to allow energy to get to all parts of the bird's body for flight. |
| Respiration | A bird has lungs to breathe with as well as a trachea and nostrils. |
| Reproduction | A bird reproduces
sexually when a male bird places sperm in the female so that the female's
eggs are fertilized in her body. The bird lays eggs that have a protective
shell. Sometimes the male helps the female warm the eggs. Baby birds require care and therefore the birds build nests for them to live and hatch in. |
| Excretion | A bird has skin covered with feathers. They lose their feathers or molt once a year. New feathers grow back to replace the old ones. The bird has kidneys and a ureter to excrete liquid wastes and intestines and a rectum for solid wastes. |
| Symmetry | A bird has bilateral symmetry. |
| Appearance | A bird ranges in size from around two inches to seven feet. Birds can be many colors. Frequently the male is more colorful and the female is drab. |
