Reptiles CH. 34.1

I. Characteristics  A. Reptile means “one who crawls.” –The study of reptiles is called Herpetology.  B. They were the first vertebrates to make a transition to life on land.

 C. Amniotic Egg [p.838] –The total life supporting system for them. –The development of internal fertilization and the amniotic egg allowed them freedom from reproducing in water.

II. Adaptations for land life.  A. Amniotic Egg and Internal Fertilization  B. Waterproof Skin –Covered with scales. –Protects the body. –Prevents water loss.

 C. Modified Limbs –Some have legs with toes or claws. –Some have “suction cups” to help with movement.

 D. Specialized Body Systems –Most have a 3-chambered heart.  2 atria and 1 ventricle. –Alligators and crocodiles have 4 chambers.

 Reptiles are cold- blooded [cannot control their body temperature.] –Ectothermic –Endothermic= warm-blooded

III. Dinosaurs

 A. The earliest reptiles.  B. Have been extinct for millions of years.  C. Dinosaur means= “terrible lizard.”  D. Most believe that a drastic climate change caused extinction.

IV. Modern Reptiles  A. Crocodiles and Alligators  1. Live in or near water.  2. Are carnivores.  3. Their only enemy is man.

 Alligators have a broad, round snout.

 Alligators are found only in the SE U.S. and a small area of China.

 Crocodiles have a long, tapered snout. –Their teeth stick out from the bottom when the mouth is closed.

 Crocodiles are found in the U.S., Africa, and Asia.

Is it a Florida Gator……or a Florida Crocodile????????

B. Turtles and Tortoises  Turtles live in or around water.  Tortoises live only on land.  Both DO NOT have teeth, but have a strong, sharp beak.

Snapping Turtle

 There are: –Carnivores{meat} –Herbivores{plants} –Omnivores{both}

Tortoise

C. Lizards  Two species are poisonous: –1. Gila Monster –SW U.S. –2. Beaded Lizard –W Mexico

 Some change colors to blend in with the environment.  Some can alter their body to appear fierce.

Chameleon

Frilled Lizard

 Some lose their tail as a means of defense and regenerate a new one, this is called AUTONOMY.  The largest lizard is the Komodo dragon.

Tutuara

D. Snakes  1. Most snakes move in an “S” pattern.  2. Eyesight and hearing are not well developed…the sense of smell is the strongest.

3. Jacobson’s Organ  a.Two specialized pits in the roof of its mouth.  b.gathers chemicals from the air.  c.used to smell for prey.

 Have a special hinged jaw that allow them to swallow prey much larger than the size of their own head.  They “unhinge” the jaw.

E. Two Categories of snakes:  1. Nonpoisonous Ex. King snake, boa constrictor, rat snake. –a. some hold prey to the ground and swallow it LIVE. –b. some squeeze it until it suffocates.

BOA CONSTICTOR

 2. Poisonous Ex. Rattlesnakes, cobras –a. kill prey with poison injected with fangs {hollow teeth like hypodermic needles}.

Cottonmouth

Copperhead

Rattlesnake

b. Two Groups of Poisonous Snakes  1. Elapids –Small, tube-like fangs that are ALWAYS “erect”.  Coral snakes, cobras

 2. Pit Vipers –Have large fangs that fold up in the mouth when not being used.

 Have an organ between the nostril and eye called a pit.  It is a “heat-sensing” organ to find warm blooded prey.

G. Four Poisonous Snakes in AL:  1. Copperhead –Pit viper  2. Rattlesnake –Pit viper

 3. Water moccasin {Cottonmouth} –Pit viper  4. Coral –elapid

BE SAFE!  RED on BLACK, friend to Jack…King snake. YELLOW  RED on YELLOW, kill a fella…coral.

H. Two Types of Poison:  1. Hemotoxin –Destroys blood cells and alters clotting {pit vipers}.  2. Neurotoxin –Affects the normal function of the nervous system, that causes difficulty in breathing and heart function {elapids}.

 3. There are more than 2,000 species of snakes, only about 125 are poisonous.

I. Reproduction  A. Use a sense of smell to find a mate.  B. Internal fertilization.  C. No parental care is given; newborns defend themselves.

J. Types of Births:  A. Oviparous –Young hatch from eggs outside their mother’s body.  Most reptiles

B. Ovoviviparous  Young hatch from eggs kept inside their mother’s body, BUT receive no nourishment from her during development. –Other reptiles

C. Viviparous  Young are born alive and receive nourishment from the mother during development. –mammals

The End