Class Reptilia 17 D Reptile toes have claws

Class Reptilia 17 D

Reptile toes have claws

Skin • • • Special protective skin Cool, dry, leathery skin Thick to prevent water loss Scales composed mainly of keratin Most reptiles must periodically molt

Reproduction • Amniotic Egg – Lays eggs encased in shells – Maintains a suitably moist environment for the developing embryo – Internal fertilization – Hard shell develops after fertilization – Porous allowing gas exchange but keeps water in

• Most reptiles are oviparous (all turtles, crocodiles, and alligators) • Some reptiles are viviparous or ovoviviparous • Most reptiles do not care for their young

Respiration • Possess lungs from birth • Reptile lungs include alveoli which are thin airfilled sacs • Provide more surface area for gas exchange to occur

Circulation • Most have a 3 -chambered heart similar to amphibians • Reptile ventricle is partially divided by a septum which helps keep some of the oxygenated and deoxygenated blood from mixing • Crocodiles and alligators have a 4 -chambered heart

Nervous System • 5 lobed brain • Eyes • Most reptiles (excluding snakes) have a tympanum or eardrum inside an ear canal connected to an inner ear that processes sound waves • Jacobson’s organs- pits in the roof of the mouth which contain nerve endings sensitive to chemcials captured from the air by the animal’s tongue