REPTILES
I. Groups of reptiles (Class Reptilia )
include snakes, lizards, turtles , +
tortoises.
REPTILE CHARACTERISTICS
A. Body covered with scales. Reptilian scales
are composed of keratin, while fish scales
represent a type of bone. Patterns of
reptilian scales include: overlapping,
mosaic and isolated.
B. Outer covering with few or no skin glands.
REPRODUCTION IN REPTILES
C. Internal fertilization. Why is this an
important land adaptation? This prevents
the desiccation of gametes i.e. egg and
sperm.
D. Amniotic egg. What advantage is there
in having an amniotic egg? This type of
shelled egg provides an aquatic
environment that a species can hide, or
build a nest for.
Thermoregulation: heterotherms +
exotherms.
III. LIZARD VERSUS SNAKE
SOME REPTILIAN FEATURES
A. Jacobson’s organs. What are they? What are their
functions? What reptiles possess them? A pair of
Jacobson’s organs are located inside the mouth
on the upper roof. The reptile transfers taste
molecules from the air with it’s forked tongue
and transfer these molecules to the organs. The
snake, and some lizards are actually able to “taste
the air”.
B. Pit vipers. North American pit vipers include
rattlesnakes, copperheads, and cottonmouths.
What are facial pits + what is their function?
Facial pit are heat sensitive organs that detect
small changes in temperature when compared to
ambient air.
VENOMS
C. Venom- a mixture of “wild” saliva.
1. Types: Neurotoxin affects the nervous
system, especially the optic nerve + the
phrenic nerve. Heomotoxin destroys
RBC’s + blood vessels.
2. Describe how the following Arizona
reptiles administer their venom:
a. Rattlesnake: Large retractable fangs
that fold in the upper roof of the mouth.
b. Coral snake: Short, erect fangs slowly
release venom through small openings on
the front face.
c. Gila monster: venom glands are
located in the lower jaw + release venom
by means of capillary action as the lizard
bites + grinds.
REPRODUCTION
V. Reproduction:
A. Oviparous: egg laying like alligator lizard and desert spiny lizard.
B. Ovoviviparous: Female retains eggs in oviduct. No placental
transfer of nutrients, live birth, like the short horned lizard +
rattlesnakes.
VII. NUTRITION
A.
B.
C.
D.
Tortoise: herbivore
Turtle: carnivore
Snakes: carnivore
Lizards: Example of an herbivorous lizard: Chuckwalla + Desert iguana
Lizards; Example of a carnivorous lizard: Desert spiny lizard
DIVERSITY OF ARIZONA REPTILES
According to this reference, Arizona has 6 turtle
species, 49 species of lizards + 52 native snakes
of which 14 are dangerously venomous.