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.

VENOMSC. 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. Tortoise: herbivoreB. Turtle: carnivoreC. Snakes: carnivoreD. 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.