A M P H I B I A N S

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  • - - - - > 4000 living species, smallest major group of vertebrates.
  • - - - - > 1 cm - 170 cm. .legs - no legs.
  • - - - - > land. moist. water to breed.

W h a t i s ?
- - - - > "both life"
- - - - > larvae, fish like aquatic animals - breathe = gills.
- - - - > adults, terrestrial carnivores - breathe = lungs / skin
- - - - > terrestrial vs. aquatic. most live in water as baby, and grow up on land.
- - - - > larva, reason live in moist areas, also eggs do not have a shell, no scales, no fur = will dry out,
- - - - > mucous glands, keep skin moist. - - - dry skin = suffocation.

E v o l u t i o n.

  • - - - - > 360 million years ago.
  • - - - - > lungs expand easily in water, on land collapse under weight of other organs.

F o r m a n d f u n c t i o n.

- - - - > tadpoles (larvae frogs and toads) - herbivores / filter feeders. = floating plants and bits.
- - - - > eat up to half of body mass.
- - - - > tadpoles grow quickly, those who lag = starve or die, if puddle dries.
- - - - > adults = carnivorous. snap jaws open and shut. long sticky tongue.
- - - - > food = mouth - esophagus - stomach. - small intestine - large intestine/colon. cloaca = stores waste until expelled.

R e s p i r a t i o n.

  • - - - - > ´╗┐breathe = lungs, mouth cavities, skin.´╗┐
  • - - - - > terrestrial salamanders = no lungs.
  • - - - - > skin important respiratory organ - carbon dioxide removed. + oxygen taken in.
  • - - - - > cannot get rid of excess carbon dioxide through skin.
  • - - - - > inhale - exhale = mouth cavity with air, close mouth, force air back through glottis in lungs.
  • - - - - > keeps air in lungs for short time.
  • - - - - > croak = forcing air from sacs over vocal cords in throat. can even croak under water.

I n t e r n a l T r a n s p o r t.

- - - - > circulatory system in lungs - closely linked to development of lungs.
- - - - > forms double loop. 1) carries oxygen-poor blood from heart -> lungs & take oxygen-rich blood from lungs -> heart. 2) transports oxygen-rich blood from heart -> rest of body & oxygen-poor blood from body -> heart.
- - - - > heart 3 chambers = left, right atrium & ventricle.
- - - - > tadpoles = 2 chambered hearts - single loop circulatory system. change into double loop as adult.

E x c r e t i o n.

  • - - - - > kidneys to eliminate waste from bloodstream.
  • - - - - > urine travels through tubes called ureters -> cloaca. directly outside, or stored in bladder.

R e s p o n s e.

- - - - > well-developed nervous/sensory systems.
- - - - > large eyes, bulge from head.
- - - - > surface of eye protects from damage underwater, and kept moist on land. (transparent nictitating membrane) inside eyelid.
- - - - > don't see color as well as fish.
- - - - > no external sound collectors, very sensitive.
- - - - > croaks, peeps, variety of calls to find mate. hearing vital to survival and reproduction.
- - - - > lateral line system - detect water movements.
- - - - > hot cold weather, hiding in sheltered spot, underground burrow & enter dormant state.
- - - - > protection: run away quickly, camouflage, distasteful/toxic chemicals (mucous coating), warning colors (wave tail/freeze to show off colors)

R e p r o d u c t i o n.

  • - - - - > male climbs on females back & squeezes.
  • - - - - > female release 200 eggs -> male fertilizes.
  • - - - - > eggs sticky, attach underwater plants.
  • - - - - > not all external and oviparous.
  • - - - - > many internal - either oviparous, ovoviviparous, viviparous.
  • - - - - > Salamanders - deposit packet of sperm on ground - performs elaborate dance persuading female to pick up sperm packet with cloaca.
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S a l a m a n d e r s.

- - - - > keep tails, even adults.
- - - - > adult & larvae = carnivores.
- - - - > fossil = 3 meters long. modern = 15 centimeters.
- - - -> live = moist woods, tunnel under rocks and rotting logs.
- - - - > mud puppy & axolotl = live in water.
- - - - > crimson spotted newt = back and forth. ( aquatic larvae - emerge live on land as RED EFT, 1/2 years changes to green w/ red spots - return to water to breed.

F r o g s a n d T o a d s.

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  • - - - - > frogs = in or near ponds/streams. toads = moist woods,
  • - - - - > managed to live dry places using water permeability of skin to advantage. burrow deep in soil press skin against walls of burrow, skin functions like root hairs of plant. osmotic pressure, water moves out of soil into toad.
  • - - - - > potent toxins. eg. marine toad squirt toxins up to 1 meter = blind/injure predators.
  • - - - - > tropical tree frogs = kill humans/large animals. ( native tribes use to poison their arrows) (poison arrow frogs) one species sooo powerful 0.00001 gram can kill human !

F i t I n t o W o r l d.

- - - - > adults - prey on insects. tadpoles - quantities of algae. = affecting energy balance of bodies of water.
- - - - > do not interact, frog legs delicacy by some.
- - - - > native hunters use poison on arrows, to hunt large animals.
- - - - > mystery why salamanders can regenerate lost limbs, frogs cannot. Researchers are hoping to use this method for humans who have lost limbs to accidents or birth defects.