The Reptiles




BIO190: The Class: Reptiles: Lesson 29

The Reptiles

Open and explore the sites below for an introduction to the reptiles.
Those Diverse Diapsids

Reptiles

Royal Tyrrell Museum Tour

Herpetology is the study of amphibians and reptiles.
NAU's Department of Biological Sciences offers a course in herpetology. Contact the Biology Department's Advisement Center for details at 520-523-9304.

Phylum Chordata
Subphlum Vertebrata
Superclass Gnathostomata
Class Reptilia (3 orders)

Members of the paraphyletic class Reptilia include the first truly terrestrial vertebrates. With nearly 7000 species occupying a great variety of aquatic and terrestrial habitats, they are diverse and abundant.

To learn about reptile classification visit this web site:

Classification of Reptiles

For information on Dinosaurs browse these web sites:

Dino Russ's Lair

Dinosaur Links

The Dinosaur Reference Center

Dinosaur Digs

Dinosaur Eggs

DNA to Dinosaurs

The following are general characteristics of reptiles:

scales cover body

glands (few in skin)

tetrapods
(usually 5 toed)

bony skeleton

respiration
(lungs only)

circulatory system

three-chambered heart (exception crocodilians with 4 chambers)
nucleated RBCs

ectothermic

excretory system
(kidneys)

nervous system
(brain: pg. 552 for more)

reproduction
(dioecious)

fert. internal

eggs with calcium based or leathery covering

Characteristics of Reptiles that distinguish them from Amphibians

tough, dry skin with scales
shelled eggs
crushing jaws
copulatory organ
circulatory system more advanced
lung development
water conservation
terrestrial locomotion more efficient
more complex nervous system

Order Testudines (figs. 29-6 --> 29-10)

Turtles do not appear in the fossil record until the Upper Triassic, some 200 million years ago.

Explore these web sites for more information on turtles:

Sites for Turtles, Tortoises, and Terrapins

Endangered Reptiles and Amphibians

Sea Turtles

anapsids
turtles, tortoises
carapace, plastron
no teeth
can use cloacal respiration
sensory
1. hearing (poor)
2. color vision
3. smell (acute)
nest temp can affect sex of hatching (also crocs and alligators; some lizards) low = males; high = females
oviparous

Order Squamata (3 suborders)

The squamates are the most recent and diverse products of diapsid evolution, making them approximately 95% of all known living reptiles.

Included in this order are lizards, snakes, and worm lizards.

diapsids
Suborder Sauria (figs. 29-11--> 29-16)
1. lizards
2. habitats
3. various types (pg. 557)
4. poisonous lizard
  (Gila monster)
5. oviparous
Suborder Amphisbaenia (fig. 29-17)
The somewhat inappropriate common name "worm lizards" describes a group of highly specialized burrowing animal with no exterior appendages.
1. "worm lizards" What a misnamed animal!!
2. burrowing
3. no ext appendages
Suborder Serpentes (figs. 29-18 --. 29- 29-24)
1. snakes
2. no limbs
3. flexible lower/upper jaws
4. cornea
  (spectacle)
5. sensory
  1. vision (poor)
  2. hearing (limited)
  3. chemical detection
    1. Jacobson's organs
    2. forked tongue
  4. smell
  5. heat
    1. pit vipers
      American Pit vipers
6. movement types
7. gathering food
  1. poison
    1. neurotoxic
      Snakebite Emergency Information
    2. hemolytic
  2. contriction
8. oviparous/ ovoviviparous

Order Sphenodonta

The order Sphenodonta is represented by two living species of the genus Sphenodonof New Zealand.

tuatara
habitat
parietal eye
slow rate of evolution

Order Crocodilia (figs. 29-5 & 29- 27)

crocodiles and alligators
can use cloacal respiration
habitat
oviparous
see turtles for info on nest temp vs. sex ratios

Once you have completed the lesson, you should go to Assignment 29-1.

E-mail Sylvester Allred at Syl.Allred@nau.edu