REPTILIA CLASS, VERTEBRATA

*they are about 6000 species
*reptilia are creeping and burrowing cold blooded animals.
*they bear scales
*skin is dry, rough and without scales.
*respiration is by lungs.
*skull is monocondylic.
*except in snake there are two pair of pentadactyl limbs, each with 5 digits bearing claws.
*heart bear two auricles and partly divided ventricles
*kidneys are metanephric
*12 pairs of cranial nerves are present
*ear consists of three parts- internal, middle anr wxternal.
*snake do not possess ear.
*all reptiles are carnivorous/insectivorous, only tortoise feed entirely on vegetation.
*a typical cloaca is present.
*fertilization is internal
*e.g-Chelone(turtle), Testudo(tortoise), Chameleon(tree lizard),Naja(cobra),Bangarus(karait) etc

TESTUDO

CHELONE

NAJA

AMPHIBIA CLASS, VERTEBRATA

*It includes 3000 species.
*they are first evolved cold blooded land living animals.
*they can live on both land and water
*glands present on skin which keep it moist.
*two pairs of limbs for locomotion.
*skull is dicondylic.
*respiratory organs are lungs,buccopharyngeal cavity , skin and gills.
*heart are three chambered.
*kidneys are mesonephric.
*ear consists of internal and middle ear.
*10 pairs of cranial nerves are present.
*they breed in water.
*e.g.-Bufo (toad), Rana (frog),Hyla(tree frog), Salamandra (salamander), Ichthyophis(limbless amphibia).

BUFO

RANA

HYLA

SALAMANDRA

OSTEICHTHYES CLASS, VERTEBRATA

* habitat-both marine and fresh water fishes
* endoskeleton is cartilaginous in the embryonic stage, but in the adult forms it is replaced by bones.
*they are ectothermic( cold blooded)
* there body is streamlined
*the mouth is terminal, digestive tract leads into an anus.
*a swim bladder is usually present,helps in floating
*they have four pair of gills which are covered by an operculum
*the exoskeleton, if present comprises cycloid, ctenoid and ganoid scales.
*the heart is 2- chambered and has sinus venous and anteriosus.
* lung fishes have three chambered heart.
*kidneys are mesonephric.
*there are 10 pairs of cranial nerves.
*fertilization is generally external.
*e.g.- Labeo(rohu), Catla (katla), Muraena(eel)