Mr. Bouyer
Day 1 | Day 2 | Days 3 - 5 | Reading Assignment

Describe the characteristics of the Class Reptilia. Describe the traits of turtles, terrapins and tortoises. Use a dichotomous key to identify Texas reptile Orders.

Special Case Study Assignment:

Read the case study about Love Potion #10. You are to use the "process of science" to decide if the claims about it are true. Questions are provided in each part of the exercise to guide your research. You must have your own position on each of these questions.

1. Monday - read parts 1 and 2, explore the add for the product, and form your answers to the questions.
2. Tuesday - read part 3, use the product's website to form your answers to the questions.
3. Wednesday - read part 4 and form your answers to the questions.
4. Thursday - Conclusion

The fifth part of this exercise may be done later.

Animal Identification Assignment.

What one thing about the appearance of skinks sets them apart from all other Texas lizards?

Class characteristics:

Dry body covered with scales
Toes with claws
Well developed lungs with alveoli
Heart is 3-chambered (two atria and one ventricle)
Internal fertilization
Amniote egg

Lizards are in the Order Squamata, Suborder Lacertilia.

Collard lizards are in the Family Crotaphytidae. The "mountain boomer" was given its name during the early history of the state. It was thought that the lizards were making a "booming" sound heard in canyons. It is now known that the animals do not make a sound, other than hissing when threatened. They perfer a habitat that includes rocky areas with bare dirt.

Collard lizards have the ability to lift their bodies and run on the two back legs. While it seems to be a flight response, it is probably more useful by startling whatever is chasing the lizard. The slight hesitation this causes may be the difference between escape and being caught.

Texas is also home to the Texas horned lizard, Phrynosoma cornatum. Over the last 30 years, the numbers of horned lizards have dropped dramatically all across its range. Several factors are thought to have caused this. The animals tend to bask on roads causing many to be hit by increased traffic. The horned lizard is also fairly slow moving, for a lizard, and children catch them for pets. They do not do well in captivity. These lizards feed almost entirely on large ants, which are not an easy food to provide for the captive animal. For this reason, those of us fortunate to see a "horny toad" in the wild should enjoy watching it, but leave it undisturbed.

One of the very few legless lizards, the slender glass lizard, Ophisaurus attenuatus, is found in Texas, usually in grassy areas. Since this lizard has no legs, it is often mistaken for a snake. A closer look will reveal that the head is shaped like a lizard, not a snake, and the animal has eyelids. No snakes have eyelids. The tail of the slender glass lizard makes up the majority of its body length. The cloacal opening, marking the end of the body cavity, is located much closer to the anterior end of the animal than the posterior. This long tail will break off with the slightest pressure. This process, called autotomy, helps them escape predators. The tail will continue to twitch after it is detatched to keep the predator's attention while the lizard escapes.

The five-lined skink, Eumeces fasciatus, is found in the open woods and grasslands of Oklahoma. Even though it moves quickly, its legs are very small. This animal is sometimes called the "blue-tailed skink" because of the color of the tail in young individuals. Its tail breaks off easily like the glass lizard.

They differ from other reptiles by having a shell. The dorsal vertebrae are fused to the upper shell, locking the turtle in its shell. Legs are attached to a pair of somewhat odd girdles.

Carapace Shields	The upper shell is the carapace, the lower shell is the plastron. The two are connected on the side by a bridge. Most turtle shells are composed of about 50 bones covered by tough, transparent scutes to protect the bones from wear. Rings form in the bones as the turtle grows, but cannot be used to tell its age. During a good year, several ridges may be formed.	Plastron Shields

Red-eared pond sliders, Chrysemys scripta, are quite common in Texas. The green shell of the young, shown at right, becomes a uniform brown to black as the animal matures, but they keep the characteristic red patch on the side of the head for which it is named.

Both the common snapping turtle, Chelydra serpentina, and the alligator snapping turtle, Macroclemys temmincki, are found in Texas. The common snapper, has a small head with low ridges on the carapace and reaches a maximum weight of around 35 pounds. The alligator snapper, has a large head with a sharp, hooked beak. It has pronounced ridges on the carapace and can grow to between 150 and 200 pounds. While the alligator snapper is a carnivore prefering deep water, the common snapper is most often a scavenger in shallow waters.

The eastern box turtle, Terrapene carolina, inhabits the open woods and grasslands of Texas. While this "tortoise" will get into the water to cool itself on very hot days, it is primarily a land animal. The plastron is hinged so that a box turtle can draw its head and front legs into the shell and close into a tight "box" when disturbed. Box turtles are territorial, remaining in an area throughout its life. The ones that you see crossing roads are most often young and have not established a territory yet. When box turtles are looking for a territory, they always move in one direction, never retracing their steps. If you ever stop to "rescue" a box turtle from the road, be sure to note the direction it is moving and put it across the road in that direction. If you don't, the turtle will just crawl back onto the road. Even when moving, they will travel only about 100 yards each day.

The term "turtle" commonly refers to all members of the Order Chelonia. But you should be aware that there are three terms that refer to the members of the order based on habitat. Their limbs are specialized for their habitat.

Turtle - True turtles are marine animals.
Terrapin - Lives in freshwater.
Tortoise - Lives on land.

Turtle Identification:

The identification of turtles depends primarily on the configuration of the head and shell, the arrangement of the plastral and carapacial shields, and the color pattern of the head and legs.

Portfolio Assignment 131:
Scoring criteria

1. Describe two different ways lizards escape from predators.
2. How did the "mountain boomer" get its name?
3. What is the prefered food of Phrynosoma cornatum?
4. What is the only poisonous lizard in the U.S.?
5. Describe how the limbs of animals in the Order Chelonia differ.
6. What characteristic of the slender glass lizard cause it to be mistaken for a snake?
7. What characteristics of the slender glass lizard makes it a lizard?
8. The shape of terrapin shells and tortoise shells is actually quite different. Use the internet to find a picture of each to demonstrate the point.
9. Why can't the growth rings in the bones of a turtle shell be used to determine its age?
10. Are there more bones on the carapace or the plastron?

Day 2

What Texas turtles have a long tail?

In-class Assignment 132:
This assignment must be turned in by the end of class today to receive credit.
Scoring criteria

1. Use this reptile key to answer the following questions.
   1. In the key, how are crocodiles separated from lizards?
   2. What turtles have a shell covered with skin?
   3. What lizard has external ear openings?
   4. What family does the mountain boomer belong to?
   5. How do you tell the difference between a crocodile and an alligator?
   6. How many claws are on the front feet of a pond slider?
   7. A pond slider and a snapping turtle of equal size are crossing a road. From a distance how do you tell the difference between the two?
   8. On the key, what is meant by "bridge"?
   9. What turtles never have webs between their toes?

Research Links:

• More about the genus Phrynosoma - University of Texas
• Amphibian and Reptile Species of Illinois - Illinois Natural History Survey
• Class Reptilia - University of Washington

Zoology Class

All lizards known as skinks have a shiny skin.

Snapping turtles are the only turtles in Texas with a long tail.