Beginning of Essay
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. come in many varieties of colors and sizes. are warm-blooded, egg-laying creatures from the aves class. Along with ....

Middle of Essay
.... 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. Approximatel ....