1. Reptiles
Chapter 41

2. Origin & Evolution of Reptiles
Section 41.1

3. History of Reptiles 350 million years old
Reptiles arose from amphibians
“Age of Reptiles” = Mesozoic era
Reptile means “to crawl”
Herpetology: study of reptiles & amphibians

4. Evolution of Dinosaurs
Dinosaurs: group of extinct reptiles that dominated life 235 mya
Triassic dinosaurs: small, carnivorous
Jurassic dinosaurs: large, carnivorous
Cretaceous dinosaurs: large, herbivorous

5. Extinction of Dinosaurs
66 million years ago
Asteroid-impact hypothesis: huge asteroid hit the earth, creating lots of dust that reduced the amount of sunlight causing massive climatic changes
Multiple-impact hypothesis: multiple asteroid impacts
Video

6. Real reason

7. Success of Reptiles
Only 4 orders of reptiles survived the mass extinction
Squamata, Chelonia, Crocodilia, & Rhynchocephalia
First totally terrestrial vertebrate

8. Amniotic Egg
Egg that encases the embryo in a secure, self-contained aquatic environment

9. Draw this picture!

10. Parts of the Egg
Amnion: membrane enclosing the fluid where the embryo floats
Yolk sac: encloses the yolk (fat-rich food supply)
Allantois: stores wastes produced by embryo
Chorion: protects the embryo
Albumen: stores protein & water for embryo

11. Characteristics of Reptiles
Section 41.2

12. Watertight Skin Thick, dry skin with keratin: Lipids & protein barrier
protein found in the outer surface cells
Lipids & protein barrier
Protects from water loss, infections, & injuries

13. Excretion Efficient systems to help conserve water
Little water loss in urine
Lungs to breathe out CO2

14. Circulatory System Composed of two loops:
Pulmonary loop: deoxygenated blood from heart to lungs, oxygenated blood from lungs to heart
Systemic loop: oxygenated blood to body, deoxygenated blood to heart

15. Heart Structure & Function
Most have a 3 chambered heart:
2 atria & 1 ventricle (partially divided)
Crocodiles have a 4 chambered heart:
2 atria & 2 ventricles
Ventricle divided by septum tissue
Reptiles can reroute blood flow away from lungs
Conserves energy
Raises body temperature quickly

16. Crocodile Heart
Septum

17. Respiration
Large, several chambered lungs with small sacs called alveoli
Increases surface area for diffusion
First vertebrae group to breath by expanding & contracting their chest
Air pressure gradient between outside and the thoracic cavity

18. Nervous System Sight is very important thus big eyes
Hearing is also important though snakes lack a tympanum
Detect ground vibrations via jaw bones
Jacobson’s organ: detects odor (smell), on roof of mouth
Heat sensitive pits below eyes of some snakes

19. Thermoregulation Definition: control of body temperature
Ectotherm: warms body by absorbing heat from the surroundings
Fish, reptiles, amphibians
Endotherm: generates heat from within
Birds, mammals

20. Advantages & Limitations of Ectothermy
Slow metabolism
Less food needed
Limitations:
Cannot live in cold climates (become dormant in winter)
No sustained exertion

21. Reproduction & Parental Care
Oviparity: egg surrounded by tough protective shell, no parental care
Ovoviviparity: eggs stored within female until just before hatching, limited parental care
Viviparity: eggs stored with female and receives nutrients from the placenta, most parental care

22. Welcome to the world!

23. Modern Reptiles
Section 41.3

24. Order Chelonia
Examples: turtles (water dwelling) & tortoises (land dwelling)
Body covered by a 2 part shell: carapace (dorsal) & plastron (ventral)
Vertebrae & ribs fused to carapace
Cannot leave shell!
Sharp beak with no teeth
Lay eggs (oviparity)

25. Two parts of the shell
Some Ohio turtles on the next few slides…..

26. Eastern Box Turtle

27. Stinkpot Musk Turtle

28. Soft-shelled Turtle

29. Blanding’s Turtle

30. Spotted Turtle

31. Snapping Turtle

32. Painted Turtles

33. Tasha, Daisy, & Bowser – in the Maroons’ house!
Video

34. Order Crocodilia Examples: crocodiles & alligators
Closest relatives to dinosaurs
All are carnivores
Eat turtles, fish, etc.

35. Order Squamata Examples: lizards & snakes
Autotomy: the ability to detach a body part often when a predatory is near
Snakes swallow prey whole
Detachable jaw

36. Types of Snakes
Constrictors: wrap body around prey and suffocate by increasing pressure
Boas, pythons, anacondas
Elapsid: inject venom through two small, fixed fangs in front of mouth
Cobras, coral snakes
Vipers: inject venom through large, mobile fangs in the front of mouth
Rattlesnakes, copperheads, water moccasins

38. Order Rhynchoephalia Example: tuatara Meaning “spiny crest”
Only two modern species
Live in New Zealand

39. 4 Order Note Cards Front Side: Back Side: Name of order
Picture (in color) of animal
Back Side:
Example organisms
Where on Earth?/habitat
Unique characteristics
Feeding patterns
Reproductive behavior