Reptiles!!!

1. Crested Gecko Reptiles!!! The Scaly Clan Brookesia Cameleon

2. Class: Reptilia----to creep • About 9,000 species • Fossils date back to 300 million years (Carboniferous period) Let’s start the day off right…click the frilled lizard!

3. Characteristics • Bilateral symmetry • Endoskeleton made of bone • 3 or 4 chambered heart • Ectothermic • Jaws have powerful crushing ability • Internal fertilization

4. Adaptations for development on land: • Dry, thick skin with scales-impervious to water • Limbs with five toes with claws for walking on land/digging • Developed lungs with alveoli • Amniotic egg • Water-conserving kidneys

5. Order Testudines “Turtles” • Shells-dorsal carapace and ventral plastron- made of an outer keratin layer and an inner layer of bone • Shell plates called scutes • Vertebrae fused to carapace • 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. • Oviparous with internal fertilization

6. Order Testudines “Turtles” • Marine turtles- paired limbs modified into flippers and can grow to 2 meters in length weighing 700 pounds. • Giant land tortoises- can weigh over 600 pounds and their low metabolic rate produces life spans exceeding 150 years. • Box turtles- hinged plastron that allows full protection of their body. • Snapping turtles- reduced shells that don’t enclose the whole body, but fierce jaws are a good defense.

7. Click to see an alligator snapping turtle! Snapping Turtle Hawksbill Sea Turtle

8. Spiny Softshell: Click to see GA turtles Giant Land Tortoise Box turtle

9. 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

10. Order Squamata “Lizards & snakes” • This order is the largest, most diverse- 96% of the living reptiles. • Skull loosely jointed at the jaw/allows squamates to seize and manipulate prey. • Viviparity or live births are limited to squamates (often associated with colder climates.)

11. Lizards • Usually four limbs present • Visible ear openings • Moveable eyelids • Ability to lose tail at fracture plane-autotomy • http://srelherp.uga.edu/lizards/

12. 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 venomous lizards. • Monitor lizards are large carnivorous lizards including largest lizard the Komodo dragon (now also believed to be venomous.)

13. Snakes • Lack limbs and eyelids (have transparent coverings) • No ear openings • Elongate body • Jaws can disarticulate-to swallow large prey • Fangs • Different types of venom in venomous species • Hemotoxins- cause heavy internal bleeding • Neurotoxins- paralyze nerve cells

14. Snakes are deaf to most sounds since they lack external ears like lizards. • Jacobson’s organs are the paired pits in the roof of the mouth used for smell. (best developed in snakes and lizards) • http://srelherp.uga.edu/snakes/ • Ovoviviparous snakes: • Copperheads • Rattlesnakes • Cotton mouths • Garter snakes

15. Snakes continued… • Coral snakes are members of the cobra family that feature neurotoxic (attack nervous system) venom. • Pit vipers, such as rattlesnakes, have hemotoxic venom for killing prey located through heat sensitive pits. • Non-venomous snakes kill prey by constriction or biting & swallowing prey.

17. Videos • http://video.nationalgeographic.com/video/animals/reptiles-animals/snakes/ • http://animal.discovery.com/video-topics/wild-animals/reptile-videos/incredible-snake-videos.htm In nature, yellow lipped sea kraits feed on eels. They also feed on small fish. The venom of the sea krait affects both muscles and nerves . It is 10 times more toxic than that of a rattlesnake. In fact, over 60 known species of sea snakes in the Pacific and Indian Oceans are venomous. In one bite, yellow lipped sea kraits can give ten times the venom needed to kill an human.

18. Order Crocodilia “Crocodiles, alligators, & caimans” • Divided into the new world caiman and alligator, and the more widely distributed crocodiles. • Four chambered heart, also found in birds and mammals. • Tongue not protrusible • Exhibit “nest tending” and some parental care

19. The gavial is a fish-eating specialist from India. The Salt-water & Nile crocodiles can reach lengths 22 feet making them the largest reptiles.

21. Videos • http://video.nationalgeographic.com/video/kids/animals-pets-kids/reptiles-kids/alligator-hatchlings-kids/ • http://video.nationalgeographic.com/video/animals/reptiles-animals/alligators-crocodiles/deadliest-crocodile-jaws/ Caiman

22. Order Sphenodontida- “Tuataras” • Only 2 species • Found on islands off New Zealand • Lizard-like but have different skull structures (2 rows of teeth in upper jaw/1 row in lower jaw) • Well developed third “parietal eye”-detects light • Burrows in day/feeds on insects at night • Considered “living fossils”- only survivor of an ancient group (others died out about 60 MYA)

24. Integument-Skin • Tough, dry skin covered with scales composed of keratin to protect against drying out and injuries. • Epidermis and dermis • No glands

25. Ecdysis “molting”- shed skin (mostly in pieces, snakes in one piece)

26. Respiration • Reptile lungs are better developed than amphibians and responsible for almost all gas exchanges (cloaca used by some.) • Have alveoli-increase surface area of the lungs • Suck air in by enlarging the thoracic cavity • No diaphragm

28. Circulation • Closed with both pulmonary and systemic systems • Two separate circulations within the heart • Either a complete partition separates the atria/ventricles or blood flow is such a way that oxygenated blood never mixes with unoxygenated blood • Most reptiles-3 chambered heart w/septum • Crocodilians-4 chambered heart

29. Amphibian heart Reptile heart

30. Nutrition & Digestion • Most are carnivores • Various methods of getting food • Venom • Sticky tongue • Constrictors • Complete digestive system

32. Excretion • Kidneys that are capable of processing wastes with little water loss • Elimination of nitrogenous wastes as uric acid-pastelike • Many lizards possess salt glands below eyes-rids of excess salt

33. Nervous System • Small brain with large cerebrum • Well developed sense organs (except hearing) • Jacobson’s organ is a specialized olfactory organ. Scents are carried here by the tongue Click

34. Click to see the horned lizard in action! • Blood sinus swells with blood to force debris to corner of eye-horned lizards rupture this sinus as a defense mechanism • Pit organs-detect temperatures different from their surroundings • Sea turtles may be able to use the Earth’s magnetic field for navigation

35. Reproduction • Sexual reproduction with internal fertilization • Oviparous • Egg covered by a tough porous shell • Eggs are laid in sheltered locations on land

36. Development • Development begins in the egg • Temperature can dictate the sex of the animal • low=male/high=female • Young hatch as lung-breathing juveniles

37. Amniotic Egg • A shelled egg contains food and protective membranes to support embryonic development. • The egg has broken the amphibian link to the water more than any other adaptation.

38. Amnion-thin membrane of fluid that encloses embryoYolk sac- (yellow part) food sourceAllantois- removes waste and functions as a lungChorion- gas exchange