170 likes | 199 Views
Reptile Notes. What do you think makes a reptile, a reptile?. QUICK QUESTION #1. Reptile Basics. Definition : cold-blooded vertebrates with lungs, scaly skin, and a special type of egg (amniotic) All these adaptations allow them to spend their entire life on land. The Amniotic Egg.
E N D
What do you think makes a reptile, a reptile? QUICK QUESTION #1
Reptile Basics • Definition: cold-blooded vertebrates with lungs, scaly skin, and a special type of egg (amniotic) • All these adaptations allow them to spend their entire life on land
The Amniotic Egg The Four Layers • Chorion: lines the shell and regulates movement of gases in and out of the shell • Yolk Sac: encloses the yolk (provides nutrients) • Amnion: encloses the fluid in which the embryo develops • Allantois: stores the embryo wastes until hatching
Tuataras (Rhynchocephalia) • Tuataras are the only surviving member of this clade. • Live on small islands off the coast of New Zealand • Active at night, hunt small animals • Gland on top of their head called “the third eye” because it contains light-sensing cells • Used to determine day length, not to see
Lizards and Snakes (Squamata) • Lizards have legs, clawed toes, external ears, and moveable eyelids • Snakes are legless lizards
Toxins • Hemotoxins: venom proteins that destroy red blood cells and disrupt blood clotting • Neurotoxins: venom proteins that disrupt nerve transmission
Alligators and Crocodiles (Crocodilia? • Alligators, crocodiles, and caimans • Live only in tropics and subtropics where weather stays warm
Turtles and Tortoises (Chelonia) • Turtles live in water, tortoises live on land (generally) • 2 parts of a turtle shell: carapace (dorsal) and plastron (ventral) • Back is fused to the carapace • Tortoises can have more dome-shaped shells • If aquatic, legs have developed into flippers
How do they eat? • Many reptiles, many forms of feeding from herbivorous to carnivorous
Digestion and Excretion • Short, simple, and slow digestive system • Herbivours eat rocks to help break down food • “Urine” stored in cloaca • The cloaca can remove large amounts of water from “urine” and restore it to the body or use glands to excrete salt • Many reptiles excrete a nitrogen based waste in the form of uric acid rather than urine
Respiration • Reptiles have lungs and inhale and exhale using various mechanisms. • Some have flaps of skin that can separate the mouth from the nasal passages…so they can breathe through their nose while their mouth is open • And some…have a special tube at the bottom of their mouth that can be extended outward so they can breathe while swallowing
Internal Transport • Can be argued that they have a three or four chamber heart (both are correct) • Crocodiles have a four chambered heart. All others have a partially divided ventricle
How do they survive? response • Senses are well developed • Great sense of smell…nostrils near the mouth and Jacobsen’s organ • Snakes can’t hear (no eardrum)….others have only a simple ear • Complex eyes • Heat sensing capabilities… • Some can detect warmth given off of bodies of the small animals they eat • Ectothermic: body temperature is determined by the environment • Endothermic: body temperature holds at a constant level
How do they survive? Movement • Reptiles with legs have larger, stronger limbs than amphibians • Reptiles without legs move by pressing large, ventral scales against the ground by expanding and contracting muscles around their ribs http://www.youtube.com/watch?v=zEto1-ZTbd4
Explain how animals like snakes can move without legs QUICK QUESTION #2
How do they Reproduce? • Most reptiles are oviparous with internal fertilization • Some lizards are ovoviviparious ~ they hold the eggs in their bodies until they hatch and then give birth to live babies