-have a notocord modified into a backbone
-closed circulatory system
-complex respiratory system
-gills, capillary buds inside
-reproduce sexually and asexually
-lateral line system
Two chamber heart, one is the atrium and the other is the ventrical. The atrium receives
the blood and the ventrical pumps the blood.
-Class Agnatha is the jawless fish, lamprey and hagfish. They have no fins,
soft skin, cartilage skeleton and gills. They are ectophermic which is where there body temperature regulates on behaviour.
-Class Chondrichthyes has sharks and rays. They have jaws, cartilage skeleton,
lateral line system, no swim bladder, paired fins and internal fertilization.
-Class Osteichthyes has lungfish, lobefin and rayfin fish. This class has
a bone skeleton. Lungfish live in deep puddles and will move into a different once theirs has dried up. Lobefin fish use their
fins to walk across the bottom of the ocean. Rayfin fiah are fish like trout and pike.
-frogs, newts, salamanders, caecilians
-have four legs
-thin moist skin
-nearly all are dependent on water for reproduction
-three chamber heart
Metamorphosis (frogs and toads)
eggs------>tadpole------->adult tadpoles have gills and two chamber
heart, adults have lungs and a three chamber heart
They have a well developed brain, a dorsal hollow nerve cord and simple eyes
Frogs have moist skin and big back legs. Toads' skin is dry on the surface and they have small back
legs. They can produce a toxin across the surface of their skin. Neither of them have tails.
Salamanders live on land and newts live in the water. They breath through their skin and don't do
Ceacilians have no legs, are blind, and eat earthworms