Ch' 43 Reptiles

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Ch. 43 - Reptiles

• Unlike amphibians, reptiles dont have to return
  to the water to reproduce. They were the first
  vertebrates to live on land during their whole
  life cycle.
• Reptiles evolved a new reproductive structure
  that allowed them to reproduce on land. What is
  this structure?
• Amniote egg

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Amniote Egg ( 5 parts)

• 1. Porous shell protects prevents water loss.
• 2. Amnion salty fluid that allows the embryo to
  float.
• 3. Allantois excretes nitrogenous waste from
  the embryo
• 4. Chorion lines the outer shell. Diffuses
  carbon dioxide oxygen through the shell.
• 5. Yolk sac supplies food for the embryo.

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Characteristics of Reptiles

• 1. Dry body covering (some with scales)
• Made of keratin to prevent water loss.
• 2. Lungs
• 3. 3-chambered heart with the ventricle partially
  divided. (alligators have 4)
• 4. Ectotherms body temperature is influenced by
  the environment.
• 5. Limbs, if present, have toes with claws.
• 6. Internal Fertilization (big advantage)

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Origin of Reptiles

• Reptiles where thought to of arose from the
  cotylosaurs. Pg. 846
• Mesozoic era is known as the Age of Reptiles.
• When were the dinosaurs thought to have become
  extinct?
• Cretaceous Period
• Dinosaur means terrible lizard

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Reptile Orders ? Cl. Reptilia

• 1. Rhynochocephalia
• Tuatara the only species in this order
• Only in New Zealand
• Parietal eye 3rd eye on the top of their head

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• 2. Chelonia ? Turtles
• Dorsal shell is called the carapace
• Ventral shell is called the plastron
• A bridge connects the two.
• Turtles are protected very well with their shell.
• Snapping turtles are one of the more aggressive
  turtles. They have a worm-like tongue to attract
  fish.

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• 3. Crocodilia
• Crocodiles alligators
• Caimans (short wide snout) gavials (long
  narrow snout).
• The only living relatives of the dinosaurs.
• Have you ever wondered why an alligator or
  crocodile doesnt swallow a lot of water when it
  has its mouth open?
• It has a glottis that prevents this.
• Have you ever heard of the Crocodile Man?

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• 4. Squamata ? Largest Order
• Lizards Snakes
• There are only 2 poisonous lizards
• 1. Gila Monster S.W. U.S.
• Has grooved teeth with venom shakes its head to
  release the venom.
• 2. Beaded Lizard Western Mexico
• Name as many lizards a possible
• Iguanas, horned toads, chameleons, skinks,
  geckos

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• Horned lizards or horny toads live around here.
  They have armored spikes covering them and when
  disturbed they hiss and squirt blood out their
  eyelids.
• Skinks and geckos have the ability to lose their
  tails and regenerate a new one .
• The term for this is autotomy.

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Snakes

• No limbs and to external ears
• There is evidence for believing that snakes once
  had legs. Some pythons boas still have
  vestigial hind legs.
• How many of you fear snakes?
• How many of you fear rattlesnakes?
• A graduate study was done on the human perception
  of snakes.

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• 2,800 species of snakes, only 300 species are
  poisonous or dangerous.
• What are the poisonous snakes of Kansas?
• Prairie rattlesnake, pigmy rattlesnake,
  cottonmouth, western diamondback rattlesnake,
  timber rattlesnake, copperhead.
• What is the largest snake in the world?
• Anaconda (33 ft.), smallest is about 4 in.
• What does molting mean?
• Snakes have between 100 400 vertebrae

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3 ways of movement in snakes

• 1. Lateral Undulation most common method for
  crawling or swimming.
• Draw
• 2. Rectilinear or caterpillar movement is the
  contract and condense of the muscles.
• Draw
• 3. Sidewinding mostly used by???
• Draw

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Snake Parts

• Nictitating membrane to cover their eyes.
• Forked tongue that is used for the great sense of
  smell.
• The branches of their tongue pick up particles in
  the air, then slide over top their Jacobsons
  organs at the roof of their mouth, which are
  sensitive to odors.
• All snakes are carnivores
• A snakes jaw can unhinge to engulf their prey.

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• What are the 2 methods snakes use to kill its
  prey?
• 3 methods of injecting venom
• 1. Vipers large front fangs (hypodermic)
• Ex. Rattlesnake, copperheads, cottonmouth
• 2. Elapids small front fangs (hypodermic)
• Ex. Cobra coral snakes

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• 3. Rear-fanged snakes bite the prey use
  grooved back teeth to inject the venom.
• Twig snakes boom slang snakes of Africa

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• 2 types of poisons in venom
• 1. Neurotoxins affects the nervous system
• Cant breath or swallow
• 2. Hemotoxins affects the circulatory system
• Destroys the blood vessels (rupture)
• Some snakes use pits to detect heat from
  warm-blooded mammals. (pg. 836)
• Name the snake that can eat a rattlesnake?
• King snake

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Reproduction

• Internal Fertilization
• Oviparous lays the eggs outside her body.
• Ovoviviparous eggs are hatched inside her body.
  Not nourished
• Viviparous bear live young that are nourished
  inside her body until they are developed.
• A snake breaks through the shell by using an egg
  tooth, which is lost after it breaks through the
  egg.