Amphibians: History and Classification

  • found in moist regions

  • some found in tropical regions, deserts, and near Artic circle

  • most start life as aquatic larvae (gills?)

  • adult life on land (lungs?)

  • all require moist enviroment for reproduction bc eggs have no shell and dry up easy

  • have four strong limbs, strong bones, girdles, and muscles that let live part time out of water

  • Tetrapods- animal w/ 4 limbs

    • have 4 limbs

  • Quadrupeds: walk on 4 limbs

CLASSIFICATION

  • 3 orderes

    • Caudata: salamanders and newts

    • Anura: frogs and toads

    • Apoda: Caecilians

  • 4000 species

  • Salamanders

    • Order caudata

      • visible tail

    • long tail

    • long body

    • 2 pairs of legs

    • smooth, moist skin

    • larvae of most salamanders live rivers, lakes, streams, ponds

    • Aquatic larvae gills. replaced with lungs in adult salamanders

    • some exchange gases directly through skin (kind of like earthworms)

    • some live in water all of life (axolotl)

  • Frogs

    • Order Anura: without a tail

    • diagram

  • Caecilians

    • Order Apoda: no limbs

    • smooth skin, small eyes, and a long wormlike body without limbs

    • vertebrates

    • Blind or nearly blind

    • feed on worms and insects as burrow in moist soil of tropical forest S America, Africa, SE Asia

    • average 30 cm (14in)