Chapter 31 Reptiles and Birds

1. Chapter 31Reptiles and Birds

2. Mammals Birds Reptiles Amphibians Fishes Nonvertebratechordates Invertebrate ancestor

3. Reptiles

4. What is a reptile? • Vertebrate • Dry, scaly skin where scales can be smooth or rough and most times shed • Lungs • Terrestrial eggs with several membranes

5. Body Temperature Control • Ectotherms – rely on behavior to control body temperature • If they want to get warm they go into the sun and if they want to cool off they get out of the sun

6. Feeding • Herbivores – iguanas • Carnivores – snakes, crocs, and alligators

7. Respiration • Most species have 2 lungs, except snakes that have one lung • Lungs are more spongy than amphibians to better exchange gases – reptiles can NOT exchange gases through skin

8. Circulation • Closed, double loop heart system • 2 atrium and 1 or 2 ventricles • Most reptiles don’t have a completed septum • Crocs and gators have most developed hearts (much like a mammal heart)

9. The Structure of a Turtle’s Heart Section 31-1 Liver Kidney Heart Cloaca Lung Bladder Digestivetract Right atrium To body From lungs To lungs Left atrium From body Ventricle Incomplete division

10. Excretion • Urine either contains ammonia or uric acid • If mostly a water animal - ammonia (which is toxic) is excreted because it can be diluted • If mostly a land animal – uric acid is excreted (a white paste because water is absorbed in cloaca)

11. Response • Active during the day and have complex eyes and see color very well • Many snakes have a very good sense of smell and some can detect heat and ground vibrations • Nostrils and sensory organs on roof of mouth that can detect chemicals • Simple ears with external eardrums

12. Movement • Legs are larger and stronger than an amphibian • They can run, walk, swim, climb, dig

13. Reproduction • Internal fertilization in which male deposits sperm inside the female’s cloaca • Most male reptiles have a penis • After fertilization, the female’s reproductive system covers the embryo with several membranes and a leathery shell

14.  The Amniotic Egg The amnion is a fluid-filled sac that surrounds and cushions the developing embryo. It produces a protected, watery environment. The allantois stores the waste produced by the embryo. It also serves as a respiratory organ. The chorion regulates the transport of oxygen from the surface of the egg to the embryo and the transport of carbon dioxide, one product of respiration, in the opposite direction. This baglike structure contains a yolk that serves as a nutrient-rich food supply for the embryo. Section 31-1 Amnion Allantois Embryo Chorion Yolk sac Shell

15. Groups of Reptiles • 1) Lizards and snakes • 2) Crocodilians – crocs, gators, caimans, and gavials • 3) Turtles and Tortoises • 4) Tuataras

16. Reptile Review • 1) What are characteristics of reptiles? • 2) How are reptiles adapted to live on land? • 3) What are the four living orders of reptiles?

17. Birds

18. Mammals Birds Reptiles Amphibians Fishes Nonvertebratechordates Invertebrate ancestor

19. Silent Spring • Rachel Carson wrote the book Silent Spring in the 1960s. As the title suggests, she describes waking up on a spring morning, hearing none of the usual chirping of songbirds and wondering what happened to them. Carson’s book increased awareness of the use of pesticides in the environment. Unfortunately, one of the chemicals that had been used interfered with the formation of the shells of birds’ eggs.

20. With a partner, discuss and answer the questions that follow. • 1. What effect would weak eggshells have on the population of birds? How might this cause a “silent spring”? • 2. If you were a legislator, what would you do about the use of chemicals such as pesticides in our environment?

21. What is a bird? • Reptilian-like animals • Maintain a constant internal body temp. • Outer covering of feathers • 2 legs that are covered with scales and used for walking or perching • Front limbs modified into wings • Feathers – mostly of protein, 2 types (contour and down feathers)

22. Form, Function, and Flight • 1) Body Temperature Control • Endotherms – can generate their own heat • High metabolism – which produces heat • Feathers insulate body

23. 2) Feeding • Beak is adapted to type of food it eats • Small birds lose heat faster so they must eat more than larger birds • Pathway of food: mouth, esophagus, crop, stomach, gizzard, intestines, cloaca

24. Anatomy of a Pigeon Brain Esophagus Lung When a bird eats, food moves down the esophagus and is stored in the crop. Heart 1 Kidney Crop Air sac Liver Moistened food passes to the stomach, a two-part chamber. The first chamber secretes acid and enzymes. The partially digested food moves to the second chamber, the gizzard. 2 Firstchamberof stomach Pancreas Large intestine Gizzard Smallintestine Undigested food is excreted through the cloaca. Cloaca 5 The muscular walls of the gizzard squeeze the contents, while small stones grind the food. 3 As digestion continues, the food moves through the intestines. 4

25. 3) Respiration • Use of air sacs and breathing tubes in the lungs insures that air flows into air sacs and out of lungs in one direction • Better because lungs are always exposed to oxygen rich air

26. 4) Circulation • Closed, double loop system • Heart has 4 chambers with a complete septum dividing heart into left and right halves • Pathway: In right atrium, right ventricle, lungs, left atrium, left ventricle, To body

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

28. 5) Excretion • Very similar to reptiles – nitrogenous waste is converted to uric acid, water is absorbed by body and a white paste is expelled from bird

29. 6) Response • Brain is relatively large for animal’s size • Can see color very well • Can hear quite well • Taste and smell are NOT well developed

30. 7) Movement • Most birds fly – Which ones cannot?? • Skeleton is changed slightly to help a bird fly – near collarbone, hollow bones • Large chest muscles

31. Wings Feathers Strong chestmuscles Efficientrespiratorysystem Efficientcirculatorysystem Homologous tofront limbs in othervertebrates Providewarmth Upward anddownward wingstrokes One-way flowof O2-rich air O2 distributionto body tissues Birds have the followingadaptations to flight which are that also that power that provide that ensure

32. 8) Reproduction • Both male and female reproductive tracts open in the cloaca • Sex organs often shrink in size when not breeding • Mating birds press their cloacas together to transfer sperm to egg (some birds have penis) • Bird eggs are amniotic with a harder shell than reptile eggs

33. Groups of Birds • 30 different orders • Largest is the perching birds – songbirds • Other groups: • Pelicans • Parrots • Birds of Prey – owls, eagles, hawks • Cavity nesting birds – woodpeckers • Herons • Ostriches • Penguins

34. Bird Review • 1) Are birds ectotherms or endotherms? • 2) What characteristics do birds have in common? • 3) How are birds adapted for flight? • Bonus: Are robins in Iowa year round?