Class Reptilia

1. Class Reptilia Chapter 20

2. Class Reptilia • Reptilia - to creep • Turtles, crocodiles, lizards, snakes, worm lizards, and tuatarans

3. Class Reptilia • First vertebrates to have amniotic eggs • Extraembryonic membranes • Protect the embryo from desiccation • Albumen • Cushions • Moisturizes • Food source • Yolk - supplies food

4. Class Reptilia • Other adaptations for land • Impervious skin • Keratin epidermal scales • Horny tales • Water conserving kidneys • Enlarged lungs

5. Class Reptilia • Subclass Anapsida – lack openings in the temple • Turtles • Subclass Diapsida • Lower and upper openings in the temporal region of the skull • Snakes, lizards, and tuataras • Subclass Synapsida – single dorsal opening in the temporal region of the skull

6. Class Reptilia • Characteristics of reptiles • Skull with one surface • Respiration by lungs • Metanephric kidneys • Internal fertilization • Amniotic eggs • Very dry skin with keratinized scales • 17 orders of Reptilia • 4 Living orders of Reptilia

7. Class Reptilia • Order Testudines • Tortoise and turtles • 225 Species of turtles • Bony shell • Limbs from internal ribs • Keratinized beak

8. Class Reptilia • Carapace - dorsal portion of shell • Plastron - ventral portion of shell • North American box turtle has hinges • Eight cervical vertebrae

9. Class Reptilia • Long Life span • 14 or more years • Up to 100 years • Sexual maturity seven or eight years

10. Class Reptilia • Oviparous • Nest contain 5 - 100 eggs • Development lasts 4 weeks to one year • Independent young • Sea turtle conservation controversy

11. Class Reptilia • Order Rhynchocephalia • Snout head • 2 living species of Tuataras • Burrow • Endangered species • Lizard-like reptiles • Virtually unchanged from extinct members • Tooth arrangement is the distinguishing factor

12. Class Reptilia • Oviparous • Share underground nesting burrows with ground-seeking sea birds • Venture out of the burrow at dawn and dusk for feeding

13. Class Reptilia • Order Squamata • Three suborders • Suborder Sauria - the lizards • Suborder Serpentes - the snakes • Suborder Amphisbaenia - worm lizards

14. Class Reptilia • Lizards • 3,300 species • Two pairs of limbs • Upper and lower jaws unite • Vary in length • Few centimeters up to 3 m

15. Class Reptilia • Habitat • Land Dwellers • Burrowers • Tree Dwellers • Reproduction • Most are oviparous • Some are viviparous or ovoviviparous

16. Class Reptilia • Gecko • Habitat • Semitropical • Climbers • Adhesion disks aid • Nocturnal • Clicking vocalization

17. Class Reptilia • Iguana • Thick Bodies • Short necks • Distinct Heads • Marine iguana • Flying iguana • Can fly 30 meters

18. Class Reptilia • Chamelions - Group of Iguanas • Characteristics • Live in Africa and India • Arboreal habitat • Long, sticky tongue • Change color • Light • Temperature • Behavior

19. Class Reptilia • Gila Monster and Mexican Beaded Lizard • Venomous lizard • Southwestern North America • Not fatal to humans

20. Class Reptilia • Suborder - Serpentes • Snakes • 2,300 Species • 300 are venomous • 30,000 - 40,000 humans die each year • Most occur in Southeast Asia • < 100 Occur in the U.S.

21. Class Reptilia • Characteristics • Lack limbs • Up to 200 Vertebrae • Skull Adaptations • Movable upper jaw • Each jaw moves independently

24. Class Reptilia • Adaptations • Differences in eye focusing • Loss of left lung • Displacement of • Gallbladder • Right Kidney • Gonads

25. Class Reptilia • Reproduction • Oviparous • Live birth • Boas • Garter snakes • Age of snakes • 135 million years old • Possible relation to caecilians

26. Reptilia • Suborder Amphisbaenia • Double walk • Worm Lizards • 135 Species • Habitat • Specialized burrowers • Africa, South America, Caribbean, and Mideast

27. Reptilia • Characteristics • Legless • Wedge shaped head • Single median tooth in upper jaw • Can move forward or backward

28. Reptilia • Order Crocodilia • Greek - lizard • 21 species • Crocodiles, alligators, gavials, and caimans • Have existed for 170 million years

29. Reptilia

30. Reptilia

31. Reptilia • Snout is elongated • Nostrils at the anterior end to help with breathing while mostly submerged • Breathe and inhale water at the same time

32. Reptilia • Tail • Muscular, elongated, and laterally compressed • Used for swimming, attacking prey, and maneuvers

33. Reptilia • Teeth • Laterally compressed teeth • Thrashing motion of capture • Swallow food whole • Death roll • Stomach • Gizzard-like • Swallow rocks and other objects

34. Reptilia • Reproduction • Oviparous • Parental Care resembles that of birds • Nesting and parental care can be traced to common ancestor of both groups

35. Reptilia • External Structures • Skin • No respiratory function • Thick, dry, and keratinized scales • Shedding of the scales is called ecdysis • Pheromones are secreted • Cryptic, Aposematic, and mimicry coloration

36. Reptilia • Support • Skeleton resembles amphibian form • Skull is elongated • Secondary palate • Increase in cervical vertebrae • Atlas and axis increase head movement • Ribs can be highly modified • Cobra • Flying lizards • Autotomy - loss of a tail

37. Reptilia • Movement • Prehistoric Reptiles • Many were bipedal • Reptile • Tetrapods • Primitive reptiles move like salamanders • Higher than most amphibians

38. Reptilia • Nutrition and Digestion • Carnivores • Tongue • Turtles and crocodiles are nonprotrusible • Lizards and anurans have sticky tongues • May exceed the lizards length

39. Reptilia • Snakes • Glottis is far forward to allow for breathing • Vipers have hollow fangs that are hinged on the maxillary • Coral, sea, and cobra snakes rigid fangs • Some cobras can “spit” • Venom glands are modified salivary glands

40. Reptilia • Body Regulation • Gas Exchange • Three chambered heart • Sinous venosus is now a pacemaker

41. Reptilia • Low oxygenated blood from right atrium to ventricle • High oxygenated blood from lungs to ventricle to left atrium

42. Reptilia • Gas exchange • Across respiratory surfaces • Partitioned into spongelike chambers • Form a negative pressure mechanism for ventilation

43. Reptilia • Temperature Regulation • Ectotherms • Can survive (-2 to 41 oC) • Need (25 to 37 oC) to live • Behavior is used for temperature regulation • Body orientation • Nocturnal • Panting • Blood diversion • Chormatophore dispersion

44. Reptilia • Nervous and Sensory Functions • Cerebral hemisphere is larger than in Amphibians • Improved smell • Jacobson organ • Snakes can smell with their tongue • Improved vision motor coordination • Ears detect vibrations • Snakes have heat sensitive pit organs

45. Reptilia • Optic lobe and Cerebellum are enlarged • Increased vision • More refined motor coordination • Independent eye movement • Different fields of vision • Dominant sense in most reptiles • Colored vision

46. Reptilia • Excretion • Kidneys have more nephrons or blood filtering units (Metanephric kidneys) • More blood flow • Higher pressure • Excrete uric acid • Insoluble in water • Can be stored as a paste

47. Reptilia • Osmoregulation • Reabsorption of water • Internal respiratory surfaces • Relatively impermeable exposed skin • Behavior • Nocturnal • Avoidance of hot surfaces • Storage of water in lymphatic spaces

48. Reptilia • Reproduction • Eggs • Land dwelling is possible • Not completely independent of water

49. Reptilia • Internal Fertilization • Egg shell forms after • Males have an intromittent organ • Sperm can be stored by the female • Turtles 4 years • Snakes 6 years

50. Reptilia • Parthenogenesis • 6 families of lizards • 1 family of snake • Parental Care • Eggs are usually abandoned • 100 species of reptiles take care of their young • American alligator • Sex is temperature dependent