Section 2 Characteristics of Reptiles Chapter 41 Reptiles Section 2 Characteristics of Reptiles

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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