Reptiles

Advanced Life ScienceRainier Jr/Sr High School

Mr. Taylor

Reptiles

• Kingdom Animalia– Phylum Chordata

• Subphylum Vertebrata– Class Reptilia

Reptile Characteristics

1. Strong, bony skeleton with toes and claws.

• Claws allow for climbing, digging, prey capture, etc.

2. Ectothermic metabolism• "cold-blooded"• limits geographic distribution and

activity (many hibernate).

Reptile Characteristics

3. Dry, scaly skin.• waterproof• allows for completely terrestrial

lifestyle.

4. Improved lungs• No cutaneous respiration, still need

much O2 for land-based activities

• Have alveoli (air sacs) surrounded by numerous capillaries

Reptile Characteristics

5. AMNIOTIC EGG!!! (A "land egg")• Amnion is a waterproof membrane that

the embryo is enclosed in…a "sea within a shell"

• Allantois: stores wastes from the embryo• Yolk and albumen: feeds the embryo

• Chorion: provides O2/CO2 exchange. This is the adaptation that truly freed

reptiles from water and allowed them to radiate into drier terrestrial biomes.

Reptile Characteristics

6. Cardiovascular system (heart)• Ventricle (pumping chamber) either partly

divided or completely divided by a septum• Gives increased to complete separation of

oxygen-rich and oxygen-poor blood in the body• Result is improved oxygen delivery to the tissues

7. Internal fertilization• Oviparous or ovoviviparous• Born looking like parents and "ready to roll"

Orders of Reptiles

Order Squamata– Lizards and snakes

• Have a hinged jaw• Periodically molt skin

Orders of Reptiles

Order Squamata– Family

Gekkonidae: the geckos• Excellent

climbers due to "velcro" feet

• Easily lose tails (escape strategy)

Western Banded Gecko

Orders of Reptiles

Order Squamata– Family Iguanidae:

the iguanas• Most North

American lizards in this group

• Live in all biomes

Western Fence Lizard

Orders of Reptiles

Order Squamata– Family Scincidae:

the skinks• Slim bodies with

shiny, cycloid scales• Limbs are small

(may even be absent)

Western Skink

Orders of Reptiles

Order Squamata– Family Anguidae: the

alligator lizards• Have a lateral fold of

skin: allows for respiration, eggs, etc.

• Long bodies, short limbs

• Many lose tails easily

Northwestern Alligator Lizard

Orders of Reptiles

Order Squamata– Family Colubridae:

the colubrids• The most common

type of snake in N. America

• No hollow fangs, only a few are poisonous, not dangerous in our area

California Mountain Kingsnake

Orders of Reptiles

Order Squamata– Family Colubridae:

the colubrids

Northwest Garter Snake

Orders of Reptiles

Order Squamata– Family Elapidae:

the Coral Snakes• This family includes

cobras, mambas, and coral snakes

• Highly dangerous neurotoxin

• Non-moveable hollow fangs

looks a lot like the harmless

California Mountain Kingsnake

Texas Coral Snake a dangerous snake

Orders of Reptiles

Order Squamata– Family Viperidae:

pit vipers• Rattlesnakes,

cotton-mouths, and copperheads

• Have moveable fangs

• Inject hematoxin mix

Cottonmouth

Western Diamondback Rattler

Copperhead

Orders of Reptiles

Order Chelonia (old name Testudines)– Turtles and Tortoises

• Have a protective shell– Carapace is the top– Plastron is the bottom

• Tortoise shell is dome shaped-land dwelling

• Turtle shell is streamlined-water dwelling

Orders of Reptiles

Order Chelonia (old name Testudines)

Orders of Reptiles

Order Crocodylia– Crocodiles, alligators, caimans, gavials

• Exhibit good parental care (including after hatching)

• Have a 4 chambered heart! resulting in maximum oxygen delivery to tissues

• Eyes and nostrils located "above the waterline" allows them to stay almost completely submerged while hunting

Orders of Reptiles

Order Crocodylia– Crocodiles, alligators, caimans, gavials

• Have cardiac and respiratory adaptations that allow them to take prey underwater for death and dismemberment.

• Have an adaptation in their hips that also is seen in birds and mammals (possible common ancestor) and allows bipedal movement.

• Alligators have U-shaped snout• Crocodiles have narrow snout with lower

"fangs" showing

Orders of Reptiles

Order Crocodylia

Orders of Reptiles

Order Sphenodontida– Tuataras

• Found only in New Zealand• An ancient order of reptiles• Nocturnal, active at lower temperatures• Slow reproducers

– May only incubate 6-10 eggs every 2-5 years– Don't reach sexual maturity until 15-20 years old

• Very endangered due to loss of habitat to non-native species (and man)

Orders of Reptiles

Order Sphenodontida