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Chapter 41 Reptiles Characteristics of Reptiles Ectotherm thick, dry, scaly, waterproof skin (prevents animal from drying out or injury) 4 legs w/claws (claws used for digging, climbing, running) vary in size, shape, color live on every continent except Antarctica
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Chapter 41 Reptiles
Characteristics of Reptiles • Ectotherm • thick, dry, scaly, waterproof skin (prevents animal from drying out or injury) • 4 legs w/claws (claws used for digging, climbing, running) • vary in size, shape, color • live on every continent except Antarctica
Live in every ocean except the polar regions • breathe w/lungs • 3 chambered heart (lower chamber partially divided to keep oxygen rich blood from blood of the body) Mmmm!!!
Origins of ReptilesAge of Reptiles (dinosaurs)Mesozoic Era 225 million to 65 million years ago
Development of the Amniotic Egg • Internal fertilization • complete environment for the embryo • egg has a leathery shell • hatch fully developed • Parts of the egg: • - Yolk: large food supply • - Amnion: filled w/fluid; shock absorber • - Allantois: gas exchange which then goes to the pores on the shell
Modern Reptiles (3 orders)Order Turtles • Can be found anywhere on earth that you find reptiles • body covered by a hard shells on top & bottom (carapace) • most can withdraw into the shell • no teeth; use beaks to break off food • omnivores (algae, fish, jellyfish)
Long, slender snouts aggressive can attack large animals easily Broad snouts less aggressive eat fish, turtles, water birds Order Crocodilia Crocodiles & Alligators Gavial: found in India, eat fish, slender jaws w/more than 100 teeth *all found in or near water in tropical climates
Order Lizards & Snakes *these make up the largest group of reptiles • Lizards • movable eyelids • external ears • legs w/clawed toes • feed on reptiles, insects, spiders, worms, mammals • largest are the monitor lizards (Komodo Dragon)
Chameleon Komodo Dragon
Snakes • no external ears; “hear” by vibrations rather than sound waves (vibrations are picked up by lower jawbone & conducted to bones in inner ear which carries message to brain) • Use tongue to smell things
unhinge their jaw & slide their mouth slowly over prey; teeth help hold prey in position • Constrictors: slowly suffocate their prey ex: boa, python, black rat snake
venom: kill w/venom (2 kinds) • - neurotoxin: paralyzes the nervous system, usually causes death in less than 20 minutes ex; cobra, coral snake
- hemotoxin: destroys blood cells, usually causes death in 48 hours or less ex; rattlesnake, cottonmouth, copperhead
Some snakes desired by farmers because they eat rodents ex milk snake, hog nose, rat snake
Maternal Care in Reptiles • Most fish, amphibians, & reptiles do not provide care for their young • but alligators & crocodiles stay near the nest & guard the eggs; they often respond to sounds made during hatching, dig out the babies and carry them to water