Reptiles and Amphibians What Makes a Reptile a Reptile? • • • • Air-breathing Ectothermic (cold-blooded) Vertebrates Skin covered in scales and/or scutes (bony outside part, like a shell). • Tetrapods (four limbed) • Lays eggs with shells • Inhabit every continent with the exception of Antarctica. • Originated around 320-310 million years ago 4 Main Groups of Reptiles • • • • • 1) Crocodilia- 23 Species Crocodiles Gavials Caimans Alligators Difference Between Crocodiles and Alligators • You can't see an alligator's teeth when it's mouth is closed; its lower teeth fit snugly into pits in the upper jaw. In contrast, a crocodile's lower teeth are always visible. • Alligators have a broad snout, while crocodiles have a thinner snout. • Alligators tend to be grayish black in color, whereas crocodiles have a light tan appearance. • Alligators can only be found in the southeastern United States and in some parts of China. Crocodiles can be found all over the world. • In the wild, alligators tend to run away while crocodiles prefer to fight. 4 Main Groups of Reptiles • 2) Sphenodontia – 2 species • Tuataras • • • • 3) Squamata -approximately 9,150 species Lizards Snakes Worm lizards • • • • 4) Testudines - over 300 species Turtles Terrapins Tortoises Size Range of Reptiles • Extant reptiles range in size from a tiny gecko, Sphaerodactylus ariasae, which can grow up to 17 mm to the saltwater crocodile, Crocodylus porosus, which may reach 6 m in length and weigh over 2,200 lb. What Makes an Amphibian an Amphibian? • Ectothermic (cold-blooded) • Vertebrates • Eggs are not surrounded by membranes (shells) • Eggs are layed in water • Tetrapods (4 limbs) • Born with gills – some retain gills for life, while others have gills that mature into adult lungs. • Skin is used for respiration or exchange of gases. • 6,500 species • Evolved out of fish over time. 3 Main Groups of Amphibians • 1) Anura - frogs and toads Differences Between Frogs and Toads Frogs • two bulging eyes • strong, long, webbed hind feet that are adapted for leaping and swimming • smooth or slimy skin (generally, frogs tend to like moister environments) • Frogs tend to lay eggs in clusters. Toads • stubby bodies with short hind legs (for walking instead of hopping) • warty and dry skin (usually preferring dryer climates) • paratoid (or poison) glands behind the eyes • The chest cartilage of toads is different also. • Toads tend to lay eggs in long chains. • 2) Caudata - salamanders and newts • 3) Gymnophiona caecilians limbless amphibians that resemble snakes Caribbean Amphibian! • http://www.youtube.com/watch?v=tCDshh48 ypg Differences Between Reptiles and Amphibians • Reptiles include alligators, crocodiles, turtles, and snakes. • Amphibians include salamanders, toads, and frogs. • Reptiles are covered with scales, shields, or plates, and their toes have claws. • Amphibians, on the other hand, have moist, glandular skins, and their toes lack claws. • The eggs of reptiles have a thick, hard shell that protects the developing embryo from moisture loss, even on dry land. • In contrast, the eggs of amphibians lack a hard outer covering and, thus, must be laid in water or in damp places. • Finally, young reptiles are miniature replicas of their parents in general appearance, although not always in coloration and pattern. • Juvenile amphibians, however, pass through a larval (wormlike), usually aquatic, stage before they metamorphose (change in form and structure) into the adult form.
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