Amphibians: the First Terrestrial Vertebrates

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Amphibians the First Terrestrial Vertebrates
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The Two Orders of Amphibians

• Kingdom Animalia
• Phylum Chordata
• Class Amphibia
• Order Caudata

• Kingdom Animalia
• Phylum Chordata
• Class Amphibia
• Order - Anura

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What is an Amphibian?

• An animal that either moves back and forth
  between water and land or live one stage of life
  in water and the other on land.
• Why do they need water?
• Amphibians, and the majority of animals that came
  after, are tetrapods.
• What is a tetrapod? Are humans tetrapods?

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What Do Amphibians Eat?

• Think about it, what else was on land at the time
  amphibians evolved?

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Order Caudata Salamanders

• Have a tail throughout their whole life.
• Most live either in caves or in moist forest
  floor litter and have aquatic larvae.
• They lay eggs, sometimes on land, sometimes in
  water.

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Salamander Reproduction

• Salamanders reproduce sexually, but do not
  actually have sex!
• The male deposits his sperm on the ground, a log,
  a leaf, etc. then the female lays in it and the
  sperm enter her cloaca.
• Cloaca a combination pee spot, poop spot, and
  vagina i.e. it all comes out the same single
  opening

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Order Anura Frogs Toads

• Most live in moist environments
• Larval form is called a tadpole.
• Toads are more terrestrial than frogs.

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Amphibian Adaptations

• Amphibian skin has lots of
• glands that secrete a mucous like substance
  that keeps them moist on land.
• Males secrete a sticky substance that helps them
  cling to females during mating.
• http//www.teachertube.com/view_video.php?viewkey
  b35fe889db419691b472
• Some produce highly toxic chemicals as a defense
  mechanism. i.e., poison arrow
  frogs, cane toads
• http//videos.howstuffworks.com/animal-planet/3577
  6-weird-true-and-freaky-cane-toad-invades-australi
  a-video.htm

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Feeding the Digestive System

• http//videos.howstuffworks.com/hsw/23876-frogs-fr
  ogs-mouths-video.htm

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Nervous Sensory Functions

• Amphibians are ectotherms, meaning that their
  blood temperature is the same temperature as
  their environment.
• Vision is well developed amphibians are sight
  feeders.
• Amphibians have clear lower lids called the
  nictitating membrane
• Smell is very developed they find mates mostly
  by smell
• Hearing is also well-developed frogs hear much
  the same as we do
• Tympanic membrane is the equivalent of our ear
  drum

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Reproduction, Development, Metamorphosis

• Development is tied to moist habitats, usually
  water.
• Warm temperatures during spring and summer are
  what induce breeding.
• Breeding between frogs is known as amplexus and
  may last from 1 to 24 hours.