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Chapter 31 Reptiles and Birds

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  1. Chapter 31Reptiles and Birds

  2. 31.1: Reptiles pgs. 796-805

  3. Characteristics of Reptiles • Class Reptilia • Means – to creep • First animals to adapt to land • Have dry scaly skin w/ claws • Have lungs • Legs at right angles from body • Provides greater support and make walking and running on land easier • Most have 3 chambered heart; some have 4 chambered heart (crocodilians)

  4. Characteristics of Reptiles • Ectotherms (cold blooded) • Most are herbivores but some are carnivores • Internal fertilization (sexually) • Lay eggs on land (amniotic eggs) • Provides nourishment and protection to developing embryo • Use sense organs to detect prey or ID chemicals

  5. What is a Reptile? • Ectotherms (cold Blooded) with dry, scaly skin, with claws on their toes • More advanced 3 chambered hearts (crocs have 4)

  6. What is a Reptile? • Amniotic eggs • Allows reptiles to be successful on land

  7. Evolution Reptiles • Reptiles were the first animals to adapt their eggs to dry habitats • First reptiles are from 350 mya • Did not become common until about 40-50 million years later when the conditions of Earth were drier

  8. Mammal-Like Reptiles • At the end of the Permian Period ~245 mya, a great variety of reptiles roamed the Earth

  9. Mammal-Like Reptiles • Displayed a mixture of mammalian and reptilian characteristics • Dominated many land habitats • Became extinct in just a few million years • Replaced by another group of reptiles…

  10. Enter the Dinosaurs • Late Triassic and Jurassic periods • Two groups of large aquatic reptiles swam in the seas • Ancestors of modern turtles, crocodiles, lizards, and snakes populated many land habitats

  11. Enter the Dinosaurs • Dinosaurs were everywhere! • Saurischia: lizard-hipped dinosaurs • Ornithischia: bird-hipped dinosaurs • Dinosaurs are the ancestors of modern birds

  12. Exit the Dinosaurs • Mass Extinction 65 mya: the end of the Cretaceous Period • Caused by a dramatic series of natural disasters • Volcanic eruptions, dropping in sea level, huge asteroid or comet smashing into the now Yucatan Peninsula in Mexico, etc. • Opened up niches on land and in the sea, providing opportunities for other kinds of organisms to evolve

  13. Body Temperature Control • Reptiles are ectotherms • They rely on behavior to help control body temperature • To warm up, they bask in the sun • To cool down, they move to the shade

  14. Reptile Feeding & Respiration • Reptiles range from herbivores to carnivores • The lungs of reptiles are spongy, providing more gas exchange area than those of amphibians • Most reptiles have 2 efficient lungs to exchange gas with the environment

  15. Reptile Circulation • Reptiles have an efficient double-loop circulatory system • Their heart contains two atria and either one or two ventricles

  16. Reptile Circulation

  17. Reptile Excretion • Urine is produced in the kidneys of reptiles • By eliminating wastes that contain little water, a reptile can conserve water

  18. Reptile Response • The basic pattern of a reptile’s brain is similar to that of an amphibian • In addition to a pair of nostrils, most reptiles have a pair of sensory organs in the roof of the mouth that can detect chemicals • Reptiles have simple ears and can pick up on ground vibrations and body heat

  19. Reptile Reproduction • All reptiles reproduce by internal fertilization • Most reptiles are oviparous (lay eggs that develop outside the mother’s body) • Reptilian eggs are amniotic • They contain a shell and membranes that create a protected environment in which the embryo can develop without drying out

  20. Structure of an Amniotic Egg

  21. Groups of Reptiles • 4 orders • Squamata (snakes and lizards) • Lizards live on the ground, burrows, trees or water • Snakes - have no limbs; kill prey by constriction or venom and swallowing whole • Chelonia (turtles) • Protected by a 2-part shell (dorsal-carapace & ventral-plastron) • Some are aquatic, others are terrestrial • No teeth but powerful jaws w/ beak-like structure • Most are herbivores

  22. Groups of Reptiles • 4 orders (continued) • Crocodilia (crocodiles and alligators) • Crocodiles have long slender snouts • Alligators have short broad shouts • Fresh and salt water • 4 chambered heart • Rhynchocephalia (tuatara) • Only survivor of primitive group of reptiles

  23. Diversity of Reptiles • Lizards • Includes the largest lizard, the Komodo Dragon • Snakes • Includes rattlesnakes, copperheads, water moccasins, & coral snakes

  24. Diversity of Reptiles • Turtles and tortoises • The only with hinged shells • Crocodilians • The only Reptiles with 4 chambered hearts Carapace(Dorsal) Plastron(Ventral)

  25. Diversity of Reptiles • Snakes feed in a variety of ways: • Constrictors kill prey by suffocation • Venomous snakes kill prey by poisoning • Most snakes simply grab prey and swallow it whole

  26. Diversity of Reptiles • Reptiles have special sense organs: • “Pit” of rattlesnakes allows them to detect heat of warm-blooded prey • Jacobson’s organ in roof of snakes mouth allows them to detect odors brought in by forked tongue

  27. Ecology of Reptiles • Many are in danger because of loss of habitat • Humans also hunt them for food, to sell as pets, for their skins, etc. • Some are now protected

  28. 31.2: Birds Pgs. 806-814

  29. Pictures of Birds

  30. Characteristics of Birds • Class Aves • Feathers, wings and thin hollow bones which allow for flight • Keel shaped sternum • 4 chambered heart • Respiratory systems consist of: lungs, anterior and posterior air sacs • Endotherms (warm blooded) • Able to regulate their internal body temperature

  31. Characteristics of Birds • Internal fertilization (sexual) • Amniotic eggs w/ hard shell • Incubate their eggs (keep at a consistent temperature) • Adaptations of birds • Feathered legs and feet of ptarmigans • Modified wings and feet of penguins • Large eyes, acute sense of hearing and sharp claws of owls • Long beaks of hummingbirds

  32. What is a Bird? • Class Aves • Feathers, modified scales that provide insulation & flight • Wings, power provided by muscles attached to sternum (breastbone)

  33. What is a Bird? • Other adaptations for flight include hollow bones, high metabolism maintained by 4 chambered heart & air sacs • Endotherm, maintains a nearly constant body temperature that does not depend on environment

  34. Form, Function, and Flight

  35. Body Temperature Control • Birds are endotherms (animals that can generate their own body heat) • They have a high rate of metabolism compared to ectotherms (metabolism produces heat) • A bird’s feathers insulate its body enough to conserve most of its metabolic energy

  36. Bird Feeding • The more food a bird eats, the more heat energy its metabolism can generate • For this reason, the phrase “eats like a bird” is quite misleading – birds are voracious eaters • A bird’s beak, or bill, is adapted to the type of food they eat

  37. Bird Digestion

  38. Bird Respiration • When a bird inhales, most air first enters large posterior air sacs in the body cavity and bones • The inhaled air then flows through the lungs in a series of small tubes • A complex system of air sacs and breathing tubes ensures that air flows into the air sacs and out through the lungs in a single direction • This constant, one way flowof oxygen-rich air helps birds maintain their high metabolic rate and generates enough energy for flight

  39. Bird Circulation • Circulation • 4 chambered hearts and two separate circulatory loops

  40. Structure of Bird’s Heart Domestic pigeon Right atrium Left atrium Left ventricle Right ventricle Heart Complete division

  41. Bird Excretion • Excretion • Similar to those of reptiles – white, pasty uric acid droppings

  42. Bird Response • Response • Well developed sense organs • Well developed eyes that can see color • Excellent hearing

  43. Reproduction in Birds • Bird eggs are amniotic eggs • They have hard outer shells • Most birds incubate their eggs until they hatch

  44. Diversity of Birds • A bird’s lifestyle is determined by its type of beak and feet.

  45. Diversity of Birds

  46. Diversity of Birds