Reptiles

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Chapter 41

• Reptiles

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Characteristics of Reptiles

• Ectotherm
• thick, dry, scaly, waterproof skin (prevents
  animal from drying out or injury)
• 4 legs w/claws (claws used for digging, climbing,
  running)
• vary in size, shape, color
• live on every continent except Antarctica

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• Live in every ocean except the polar regions
• breathe w/lungs
• 3 chambered heart (lower chamber partially
  divided to keep oxygen rich blood from blood of
  the body)

Mmmm!!!
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Origins of ReptilesAge of Reptiles
(dinosaurs)Mesozoic Era
225 million to 65 million years ago
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Development of the Amniotic Egg

• Internal fertilization
• complete environment for the embryo
• egg has a leathery shell
• hatch fully developed

• Parts of the egg
• - Yolk large food supply
• - Amnion filled w/fluid shock absorber
• - Allantois gas exchange which then goes to
  the pores on the shell

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Modern Reptiles (3 orders) Order Turtles

• Can be found anywhere on earth that you find
  reptiles
• body covered by a hard shells on top bottom
  (carapace)
• most can withdraw into the shell
• no teeth use beaks to break off food
• omnivores (algae, fish, jellyfish)

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Order Crocodilia
Crocodiles Alligators

• Long, slender snouts
• aggressive
• can attack large animals easily

• Broad snouts
• less aggressive
• eat fish, turtles, water birds

Gavial found in India, eat fish, slender jaws
w/more than 100 teeth
all found in or near water in tropical climates
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Which is which?
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Order Lizards Snakes these make up the
largest group of reptiles

• Lizards
• movable eyelids
• external ears
• legs w/clawed toes
• feed on reptiles, insects, spiders, worms,
  mammals
• largest are the monitor lizards (Komodo Dragon)

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Chameleon
Komodo Dragon
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• Snakes
• no external ears hear by vibrations rather
  than sound waves (vibrations are picked up by
  lower jawbone conducted to bones in inner ear
  which carries message to brain)
• Use tongue to smell things

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• unhinge their jaw slide their mouth slowly over
  prey teeth help hold prey in position
• Constrictors slowly suffocate their prey ex
  boa, python, black rat snake

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• venom kill w/venom (2 kinds)
• - neurotoxin paralyzes the nervous system,
  usually causes death in less than 20 minutes ex
  cobra, coral snake

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- hemotoxin destroys blood cells, usually causes
death in 48 hours or less ex rattlesnake,
cottonmouth, copperhead
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Some snakes desired by farmers because they eat
rodents ex milk snake, hog nose, rat snake
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Maternal Care in Reptiles

• Most fish, amphibians, reptiles do not provide
  care for their young
• but alligators crocodiles stay near the nest
  guard the eggs they often respond to sounds made
  during hatching, dig out the babies and carry
  them to water