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=tCDshh48ypg

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.