Amphibians

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Amphibians
having two lives land and water
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General characteristics

• smooth, moist skin

• 3 chambered heart

• external fertilization

• cold blooded - ectothermic

• respire with gills ( young ),
• lung and/or skin in adults

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• eggs must be laid in moist
• environment
• eggs are jelly-like.

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amplexus - male clasps female and sheds sperm
onto her eggs
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• Fish 2 chambered heart
• 1 atrium and 1 ventricle
• a low pressure system
• one continuous loop

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From body
atrium
ventricle
To lung
FISH HEART
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• Amphibians -
• 3 chambered heart
• with 2 circulatory loops
• pulmonary loop
• ( heart lung heart )
• systemic loop- delivers O2
• ( heart body heart )

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From lung
AMPHIBIAN HEART
atrium
From body
ventricle
To lung
atrium
To body
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from lung
to lung
from body
Blood to body is pressurized
organs, muscles
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Amphibians evolved 350 mya in The Devonian
period from lobe finned fish like the
Coelocanth
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Lobe finned Coelocanth
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Icthyostega ancient amphibian
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• There are 3 orders of amphibians
• Anura - frogs and toads
• Caudata salamanders
• Caecilians - legless

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caecilians
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Cooked frog legs