1. Section 2 Characteristics of Reptiles
Chapter 41 Reptiles
Section 2
Characteristics of Reptiles

2. Differences What are some differences between a snake and a turtle?
What are some differences between a lizard and crocodile?

3. Circulatory System
Pulmonary loop- carried deoxygenated blood from the heart to the lungs and returns oxygenated blood to the heart
Systemic loop- transports oxygenated blood to the tissues of the body and returns deoxygenated blood to the heart

4. Heart Structure & Function
Lizards, snakes, turtles, tuataras- two atria & one ventricle- divided by a wall of tissue- septum
Crocodiles- two atria & two separate ventricles
Very little blood (good & bad) mixes in reptile hearts

5. Heart Structure & Function
Pumping blood through lungs requires energy
Inactive reptiles do not need a lot of oxygen
Aquatic reptiles don’t breathe while underwater
Heart pumps blood to body and reduces circulation in lungs

8. Respiratory System
Alveoli- lining of the lungs folded into numerous small sacs
Large lungs- absorb much oxygen
Snakes- only use right lung
Expand ribcage to fill lungs- humans use similar technique

10. Nervous System Cerebrum is larger than amphibian- controls behavior
Optic lobes (control eyesight) also larger
Eyes are large
Hearing is important- sound waves to eardrum (tympanum) to columella

12. Nervous System
Jacobson’s organ- specialized sense organ located in the roof of mouth- senses odors
Snakes use tongues to sense environment
Snakes are able to detect heat from heat-sensitive pits located below each eye

14. Thermoregulation Control of body temperature- thermoregulation
Ectotherm- warms body by absorbing heat from surroundings
Endotherm- mammals & birds- rapid metabolism which generates heat to warm body

15. Thermoregulation
Aquatic ectotherms- keep body temperature around the same as water
Terrestrial ectotherms- keep body warmer due to sunlight & basking
Endotherms- feathers, body fat, hair to retain heat

16. Thermoregulation
Reptiles need to bask often in order to raise body temperature
Example: Lizard body temperature drops at night. In order for lizard to become active, it must bask in the sun.
Reptiles need to raise body temperatures to digest food

19. Advantages & Limitations to Ectothermy
Reptiles- slow metabolism- need little energy & food
Ectotherms cannot live in cold climates, if climate is cool for a long period of time, reptile will hibernate

20. Reproduction
Oviparity- female’s reproductive tract encloses each egg in tough protective shell
Ovoviviparity- retain eggs within the female’s body (eggs may be laid or may hatch in female body)
Viviparity- shell does not form around egg & young are retained inside until born

22. Reproduction
Placenta- nutrients & oxygen are transferred from mother to embryo

23. Parental Care
Crocodiles & alligators provide most parental care of reptiles
Build nest for young
Guard against predators
Carry young in mouth & protect for over a year

26. REVIEW!!!
Compare thermoregulation in animals that are endothermic versus thermoregulation in animals that are ectothermic
Contrast oviparity with viviparity.