Transcript Chapter 41 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, tuatarastwo 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 lungshumans 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 temperaturethermoregulation
• Ectotherm- warms body by
absorbing heat from surroundings
• Endotherm- mammals & birdsrapid 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.