Reptiles

What is a Reptile? •Fully terrestrial •Dry, scale-covered skin •Ectothermic •Most have 3 chambered hearts (except alligators and crocodiles) •Internal fertilization •Amniotic eggs typically laid on land

Reptile Circulation Reptiles have a partially divided ventricle

Form & Function in Reptiles •Well developed lungs •Double-loop circulatory system •Water-conserving excretory system •uric acid – terrestrial waste •ammonia – aquatic waste (crocs & gators!) •Strong limbs •Internal fertilization •Amniotic eggs contributed to success on land

Ectothermic – have the ability to control their body temperature by basking in the sun and moving to shade during the day. Jacobson’s Organ – sensory organ located in the roof of the mouth used for detecting chemicals when reptiles flick their tongues.

Reproduction in Snakes Oviparous birth pythons & cobras (egg hatches outside mother) Viviparous copperheads, boa constrictors, rattlesnakes, & garter snakes (live birth) Ovoviviparous Water snakes (eggs hatch inside mother & young born live)

Venomous vs. Nonvenomous Characteristic Pit Viper Non-poisonous Triangle-shaped head Oval head Flat head Rounded head Elliptical pupils / Pits Round pupils / no pits

Amniotic Egg Amnion – fluid filled sac that cushions the developing embryo Chorion – regulates transport of oxygen to embryo and carbon dioxide to the outside of egg. Yolk sac – nutrient rich food supply for embryo Allantois – stores the waste produced by embryo

Orders of Reptiles Squamata (lizards & snakes) Testudines (turtles & tortoises

Crocodilia (crocodiles & alligators) Endothermic & 4-chambered heart Sphenodonta (tuatara)