Reptiles have more developed lungs than amphibians, with muscular ribs that help expand their chest cavity to draw in air through nostrils. They have a more efficient circulatory system than amphibians, with at least an incomplete separation of oxygenated and deoxygenated blood between the ventricles. Reptiles regulate their body temperature within a narrow range through behaviors like basking in the sun, and have sensory systems dominated by vision and olfaction, with hearing sensitive to ground vibrations. They have advanced kidney functions that produce concentrated uric acid waste instead of liquid urine. Most reptiles reproduce through oviparity, but some are ovoviviviparous.

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2.  Reptilian lungs are better developed than
amphibians
 Muscular ribs help them expand the chest
cavity as we do to draw in the air
 Nostrils allow them to bring in air while their
mouth is closed
 Snakes only have one long, lung that fits in
their bodies.

3.  Snakes also have a tube that projects out of the
mouth when the snake is swallowing so that it
can breathe and swallow at the same time
 The ribs of turtles attached to their shells which
prevent movement of body wall
 They exhale by contacting muscles

4.  More efficient circulatory system, higher blood
pressure
 All reptiles have at least an incomplete
separation of the ventricles
 Still incomplete separation of oxygen-rich and
oxygen-poor blood
 Crocodilians have two completely separated
ventricles

5.  All reptiles have two functionally separate
circulations.

6.  Reptiles regulate their body temperature with
in a narrow range, between 25-37
 Behavioral and physiological activities to
regulate temperature.
 lizards absorbs heat by conduction.
 Panting which releases heat through
evaporative cooling

7.  Reptiles basking in sun and warm up quickly.
 Chromatophores also aid in temperature
regulation.
 In winter, individuals may migrate to a
common site called a hibernaculum.

8.  Larger cerebral hemisphere
than the amphibians
 Optic lobes and the cerebellum
are also large
 Increased reliance on vision
 More refined co-ordination of
muscle functions.

9.  Vision - dominant sense
 In lizards eyes are movable while in snakes
permanent transparent covering is present.
 Hearing - no obvious external ear
 Not deaf - have internal ears
 No obvious response to aerial sounds
 Sensitive to vibrations carried in ground

10.  Olfaction important, but not in nostrils
 Blind-ending pouches called as Jacobson’s
pouches.
 These pouches open in secondary palate
through mouth cavity.
 Tongue carries scent
particles to organ.

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12.  Behavioral changes helps to regulate
temperature and conserves water
 During day, nocturnal habitats and avoiding
hot surfaces reduce water loss
 In water availability, reptiles store large water
quantities in lymphatic spaces

13.  Kidneys is more advanced in reptiles called
metanephric.
 Blood-filtering units called as nephrons are
present.
 Kidney lack loop of Henley, it unable to
produce liquid urine more concentrated than
their body fluid.

14.  Kidneys produce urine in the form of uric acid
 Urine is either passed out directly through the
cloaca, or stored in the urinary bladder where
water is further reabsorbed
 Uric acid crystallizes when concentrated, and is
eliminated as a white paste (like birds)

15.  Most reptiles are oviparous
 Female lays eggs that hatch outside her body
 To break out a hatchling uses a special tooth
which is lost soon after
 Others are ovoviviparous
 Female carries the eggs in her body
throughout development
 Young are born live

16.  Internal fertilization
 A pair of ducts delivers sperm into cloaca of
female
 Male inserts penis into female’s cloaca
 Female’s body coats the embryos in protective
shell, with membranes and yolk sac.

17.  Parthenogenesis
No male found higher reproductive bisexual
population
 Head-bobbing
Displays by some male lizards reveal bright
patches of colors on the throat.
 Tail waving
It is performed by male running chin along
female

18.  Vocalization
During breeding season male is hostile that may
bark and worn other males to attract females
 Mating occurs after this