chapter 41 reptiles section 2 characteristics of reptiles
TRANSCRIPT
Chapter 41Reptiles
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.