Reptiles!!! The Scaly Clan
Class Reptilia • 7000 species “Turtles, crocodilians, snakes & lizards • Tough, dry skin covered with scales composed of keratin to protect against drying out and injuries.
Class Reptilia • The skin must be shed periodically to allow for the animal to grow. • Reptile lungs are better developed than amphibians and responsible for almost all gas exchanges.
Amniotic Egg • Internal fertilization since the shelled eggs must be fertilized before they are enclosed. • A shelled egg contains food and protective membranes to support embryonic development. • Reptiles lay eggs on land, which hatch into lung breathing juveniles. • The egg has broken the amphibian link to the water more than any other adaptation.
Order Testudines “Turtles” • Shells consisting of the dorsal carapace and the ventral plastron are made of an outer keratin layer and an inner layer of bone. • Turtles have sharp plates covering the jaws instead of teeth. • Turtles have poor hearing, but a good sense of smell, acute vision, and color perception.
Order Testudines “Turtles” • Marine turtles have paired limbs modified into flippers and can grow to 2 meters in length weighing 700 pounds. • Giant land tortoises can weigh hundreds of kilograms and their low metabolic rate produces life spans exceeding 150 years. • Box turtles have a hinged plastron that allows full protection of their body. • Snapping turtles have reduced shells that don’t enclose the whole body, but the fierce jaws are a good defense.
Videos • http://video.nationalgeographic.com/video/kids/animals-pets-kids/reptiles-kids/turtle-loggerhead-kids/ • http://animal.discovery.com/tv-shows/river-monsters/videos/turtle-strikes-like-a-snake.htm
Order Squamata “Lizards & snakes” • This order is the largest, representing 95% of the living reptiles. • Joints in the palate and across the roof of the mouth allow squamates to seize and manipulate prey. • Viviparity or live births are limited to squamates and normally associated with colder climates.
Lizards are a diverse group of terrestrial, burrowing, aquatic, and arboreal species. • Lizards have movable eyelids whereas snakes have transparent coverings. • Iguanas represent a group of herbivorous new world lizards. • Chameleons are arboreal lizards of Africa with extendable tongues for catching their prey. • The American Gila monster and Beaded lizard are the only venomous lizards. • Monitor lizards are large carnivorous lizards including largest lizard the Komodo dragon.
Snakes are a group of limbless squamates. • Snakes are deaf to most aerial sounds since they lack external ears like lizards. • Jacobson’s organs are the paired pits in the roof of the mouth used for smell. • Pit vipers, such as rattlesnakes, have hematoxic (attack tissue) venom for killing prey located through heat sensitive pits.
Snakes continued… • Coral snakes are members of the cobra family that feature neurotoxic (attack nervous system) venom. • Non-venomous snakes kill prey by constriction or biting & swallowing prey.
Videos • https://www.youtube.com/watch?v=QK9Xj7eY0UU • http://video.nationalgeographic.com/video/animals/reptiles-animals/snakes/ • http://animal.discovery.com/video-topics/wild-animals/reptile-videos/incredible-snake-videos.htm
Order Crocodilia “Crocodiles, alligators, & caimans” • Crocodilians are divided into the new world caiman and alligator, and the more widely distributed crocodiles. • Four chambered heart found in birds and mammals. • The gavial is a fish-eating specialist from India. • The Salt-water & Nile crocodiles can reach lengths 22 feet making them the largest reptiles.
Videos • http://video.nationalgeographic.com/video/animals/reptiles-animals/alligators-crocodiles/croc_american/ • http://video.nationalgeographic.com/video/kids/animals-pets-kids/reptiles-kids/alligator-hatchlings-kids/