THE REPTILIAN BODY

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THE REPTILIAN BODY

• PETRA BÍROVÁ

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• TERRESTRIAL

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KEY FEATURES

• Strong bony skeleton and toes with claws
• Ectothermic metabolism
• Dry scaly, almost watertight skin
• Well developed lungs
• Ventricle of heart partly divided by a septum
• Internal fertilization

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Ectothermic metabolism

• PROBLEM!
• Metabolism is too slow too generate enough heat
  to warm their bodies.
• ?

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• PROBLEM
• Changes in enviroment?changes in the body
  temperature
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• Basking
• Seeking for shade
• Hibernation through the winter

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• PROBLEM
• Waterloss through skin (evaporation)
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• PROBLEM
• Tought skin with scales ? growth
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• PROBLEM
• Reproduction out of water, sperms can not swim,
  they and eggs would dry out
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• PROBLEM
• Fertilized egg needs a most environment in which
  it can develop
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Amniotic egg
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Oviparous reptiles
YOUNG HATCH FROM EGGS AND HEAT FROM THE
ENVIRONMENT INCUBATES THEM.

• WHAT IS THEIR PROBLEM?

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OVOVIVIPAROUS

• FEMALES RETAINS THE EGGS WITHIN HER BODY UNTIL
  SHORTLY BEFORE HATCHING
• OR THEY CAN HATCH IN HER BODY
• (e.g. hagnose snake)

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• PROBLEM
• Scaly skin doesnt permit gas exchange so it can
  not be the additional respiratory organ.
• ?

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alveoli
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• More efficient pair of lungs which surface is
  increased by small grape- shaped chambers-
  alveoli on the inner surface ot the lungs.
• Strong muscles attached to their rib- cage.

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heart

• Left and right atrium
• Partly divided ventricle by a septum
• Blood mixing
• more efficient than in amphibians
• ! Crocodiles- completly divided ventricle 4
  chambered heart !

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Thank you for attention ?