General characteristics of Reptiles

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DESCRIBES THE GENERAL FEATURES OF REPTILES

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General Characteristics of Reptiles:

General Characteristics of Reptiles Mrs. Rani Ashok Asst. Prof. of Zoology Lady Doak College, Madurai Email: eaarani@rediffmail.com

REPTILES:

Diverse group of animals Lizards Snakes Tortoises Crocodiles Extinct dinosaurs etc. REPTILES

REPTILES:

From " reptilis " meaning "creeping" REPTILES

REPTILES …:

First vertebrates which became independent of water and took possession of dry land REPTILES …

REPTILES …:

Complete colonization of land was achieved by the reptiles, which can lay their eggs on dry land. REPTILES …

REPTILES …:

Arose in Carboniferous period from Amphibian stock Flourished during Mesozoic era REPTILES …

Characteristics of reptiles …:

Terrestrial organisms Poikilothermous in nature (Regulate temperature in accordance with the external surrounding temperature) Tetrapods Characteristics of reptiles …

Characteristics of reptiles …:

Pentadactyl limbs Digits end in claws Body divisible into head, neck and tail Body covered with dry epidermal scales Characteristics of reptiles …

Characteristics of reptiles …:

Skull bears single condyle One or two temporal fossae are usually found Pineal foramen is present in the skull Teeth are simple, conical and thecodont Characteristics of reptiles …

Characteristics of reptiles …:

Heart consists of a sinus venosus , 2 auricle and 1 incompletely divided ventricle Has both left and right systemic arches Characteristics of reptiles …

Characteristics of reptiles …:

Pulmonary respiration i.e. respiration through lungs takes place 12 pairs of cranial nerves seen Metanephric kidneys with no nephrostomes Characteristics of reptiles …

Characteristics of reptiles …:

Sexes are separate Males possess copulatory organs Fertilization is internal Large eggs with considerable yolk Eggs covered by porous calcareous shell Characteristics of reptiles …

REPTILIAN EGGS …:

REPTILIAN EGGS …

Characteristics of reptiles …:

Embryo develops within embryonic membranes – amnion and allantois Most reptiles are oviparous Some snakes are viviparous Characteristics of reptiles …

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