reptile

1. The
Reptile
Body

2. Characteristics of Reptiles
 Reptiles were the first vertebrates to live on land
 Scales keep moisture inside
 Reptiles eggs DO NOT dry out on land
 Live in a variety of different habitats
 Tropical forests, desserts, oceans, rivers, and lakes
 Are NOT found in very cold regions because they are cold-blooded

3. Characteristics of Reptiles
• All reptiles share the following characteristics
– Bodies covered in scales
– Clawed toes
– Ectothermic (cold-blooded) metabolism
– Lack feathers or any form of hair
– An internal skeleton
– A heart with a partially divided ventricle
– Lungs
– Reproduce Internally
• Amniotic eggs

4. Reptile Movement and Response
 The following adaptations allow reptiles to live in
dry environments
 A strong skeleton
 Claws
 legs positioned under the body
 highly developed vision
 Since Reptiles are cold-blooded this limits their
habitat range

5. Endoskeleton
 Reptiles have a strong skeleton made of
bone
 Most reptiles have two pairs of limbs
Snakes and some lizards lack legs
Legs positioned under the body
allow reptiles to move faster and
easier on land
 Reptiles have toes with claws
Use claws for climbing and digging
Enables reptiles to run quickly
over short distances

6. Sensory Systems: Vision
 Vision is an important sense
Rely on sight to detect
predators and prey
 Eyes of reptiles are very large and
have movable eyelids
Snakes and geckos lack
movable eyelids
Reptiles that are active at
night can see very well in
the dark

7. Sensory Systems: Hearing
 Hearing is a very important
sense organ to reptiles
 Sound waves first strikes the
tympanum (ear drum) and are
then transmitted to the inner
ear
 Snakes lack a tympanum
 They detect ground vibrations
through the bones of their jaw

8. Sensory Systems: Jacobson’s Organ
 Reptiles sticks their tongues out to collect small particles
from the air
 The small particles come in contact with the Jacobson’s
Organ
 The Jacobson’s Organ is a specialized sense organ in the
roof of the mouth of many reptiles, it is sensitive to odors
 Used to “taste” the environment

9. Sensory System
 Snakes are able to detect heat
given off by warm-bloodied
prey
 Use heat sensitive pits below
each eye
 The pits allow the snake to
detect the distance and
direction of the prey

10. Body Temperature Control
 Reptiles are ectothermic
 They CANNOT heat their own body by using their metabolism
 A reptile’s body temperature is mostly determined by the
temperature of its environment
 Reptiles may bask in the sun to warm up or seek shade to cool
down
 At very low temperatures reptiles slow down and may not be
able to function

11. Respiration and Circulation
 The following adaptations allow reptiles to have
more efficient respiration and circulation
 1. Lungs with a large surface area
 2. A heart that is almost completely divided into
four chambers

12. Reptile Lungs
 Reptile lungs have many internal folds, which
gives the lungs a large surface area for oxygen
exchange
 Strong muscles in the rib cage allow air to move in
and out of the lungs quickly, which increases lung
efficiency

14. Reptile Heart
 The septum partly divides the ventricle into right
and left halves
 Enables a much better, but still incomplete,
separation of oxygen-rich and oxygen-poor blood
 Oxygen is delivered to the body cells more
efficiently in reptiles than in amphibians

15. Reptile Reproduction
 Reptile reproduction occurs through internal fertilization
 Many reptiles are oviparous: the young hatch from eggs that
are laid outside the mother’s body.
 Some snakes are lizards are ovoviviparous: fertilized eggs
remain inside the female’s body for a long time and hatch
inside the female
 This protects the eggs from predators
 Most reptiles DO NOT care for their young
 Alligators and crocodiles are an exception

16. Amniotic Eggs
 An amniotic egg contains both a water supply and
food supply
 Amniotic eggs are key to a reptile’s success as a
terrestrial animal
 They are watertight

17. Amniotic Egg Structure
 The shell and albumen protects
and cushions the embryo
 Also a source of nutrients
 There are four membranes in the
amniotic egg
 1. Amnion- cushions the embryo
 2. Yolk Sac- contains the embryo’s
main food supply, blood vessels
attach here
 3. Allantois- stores waste and is the
embryo’s organ for gas exchange
 4. Chorion- allows oxygen to enter
the egg and carbon dioxide to leave
the egg