Reptiles Life Science 15 4


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Reptiles Life Science 15 4

  1. 1. REPTILES 15.4 By. Chelsea Henry
  2. 2. What is a reptile? <ul><li>A reptile is an ectothermic vertebrate with dry scaly skin. </li></ul><ul><li>They have a thick dry waterproof skin covered with scales to prevent drying out and injury </li></ul>
  3. 3. Variety in Reptiles <ul><ul><li>They vary in size, shape, and color </li></ul></ul><ul><li>Reptiles live on every continent except Antarctica and in all the oceans except in polar regions </li></ul><ul><li>Reptile’s hearts have three chambers with the lower chamber partially divided </li></ul><ul><li>Oxygen rich blood coming from the lungs is kept separated from blood that contains carbon dioxide returning from the body </li></ul>
  4. 4. Development of the Amniotic egg <ul><li>Eggs of reptiles are fertilized internally inside the body of the female </li></ul><ul><li>After fertilization, the female secretes a leathery shell around the eggs and lays them on land </li></ul><ul><li>They lay amniotic eggs containing membranes to protect and cushion the embryo and to help get rid of waste </li></ul><ul><li>Small holes in the shell called pores, allow oxygen and carbon to be exchanged </li></ul><ul><li>The yolk is a large food supply for the embryo to use as it develops </li></ul>
  5. 5. Origins of Reptiles <ul><li>Reptiles first appeared in the fossil record nearly 280 million years ago </li></ul><ul><li>The earliest reptile was called cotylosaurs </li></ul><ul><li>The Mesozoic era, which lasted from 225 million to 65 million years ago is considered to be the ‘Age of the Reptiles’ </li></ul><ul><li>Dinosaurs descended from early reptiles </li></ul>
  6. 6. Modern Reptiles <ul><li>Modern reptiles descended from cotylosaurs </li></ul><ul><li>Today there are three orders of reptiles; turtles; crocodiles and alligators; and lizards and snakes </li></ul>
  7. 7. Turtles <ul><li>Turtles can be found on almost every continent and in most of the worlds oceans </li></ul><ul><li>Turtles bodies are covered by a hard shell on bottom and top </li></ul><ul><li>Most can withdraw into their shell for protection </li></ul><ul><li>Turtles have no teeth and use their beaks to feed on insects, worms, fish and plants </li></ul>
  8. 8. Crocodiles and Alligators <ul><li>From the order crocodilia </li></ul><ul><li>Can be found in or near water in tropical climates </li></ul><ul><li>Crocodiles have long slender snouts and are aggressive </li></ul><ul><li>Crocodiles can attack large prey such as cattle </li></ul><ul><li>Alligators are less aggressive </li></ul><ul><li>They have broad snouts and feed on fish, turtles, and water birds </li></ul>
  9. 9. Lizards and Snakes <ul><li>Lizards and snakes make up the largest group of reptiles </li></ul><ul><li>Lizards have movable eyelids, external ears and clawed toes on each foot </li></ul><ul><li>They feed on other reptiles, insects, spiders, worms, and mammals </li></ul><ul><li>Snakes don’t have external ears or legs </li></ul><ul><li>Snakes hear vibrations through the ground </li></ul><ul><li>Sound waves in the ground are picked up by the lower jaw bone and conducted to the inner ear </li></ul><ul><li>From there, the snake brain interprets the vibrations </li></ul><ul><li>Snakes are carnivores </li></ul><ul><li>Some snakes are constrictors that wrap around prey and crush them to death others are venoms and poison their prey with a bite </li></ul><ul><li>Snakes feed on rodents and help control their population </li></ul>
  10. 10. Maternal Care in Reptiles <ul><li>Most reptiles show little or no care for their eggs once they’ve been laid </li></ul><ul><li>Turtles dig out a nest and leave </li></ul><ul><li>The development of the amniotic egg gave reptiles the ability to emerge from the egg fully formed </li></ul><ul><li>Crocodiles are very maternal. They watch over the hatchlings till they’re big enough to fend for themselves </li></ul>