Reptiles

= Phylum Vertebrata = = Subphylum Chordata = = Class Reptilia =

Body Structure
The skin of modern reptiles is covered by plates of a horny material. These scales are regularly shed and replaced, and some reptiles also have plates of bone for extra protection. A reptiles skin is hard, smooth, and dry. Reptile skin also has almost no secretory glands. They have 2 main layers of skins, the epidermis and dermis.Though snakes are often described as being "slimy," their skin is actually very dry, In fact, they only have two skin glands — a pair of scent glands that secrete a substance used to attract a mate, provide protection from predators, and mark territory. Unlike other animals, snakes continue to grow until the day they die. Consequently, snakes periodically shed their skin in a process called "ecdysis." Before shedding the skin, the snake takes on a slightly bluish hue and the eyes appear cloudy. This is caused by fluid located between the layers of skin. Mites, malnutrition, and trauma, among other things, may cause dysecdysis, or abnormal shedding. The skull of the reptile is similar to the amphibians. However, the skull of the reptiles have only a single occipital condyle, whereas amphibian skulls have two occipital condyles. Reptiles contain two kidneys that filter wates from the blood and excretes it in a watery fluid called urine. Reptiles also have a three chambered heart which includes one ventricle and two atria. The lower jaw of the reptile skull is composed of about six bones. The upper part of the reptile skull shows a number of modifications from the amphibians skull which gives the reptile a far more efficient and powerful jaw. Turtles have two parts of a shell the upper part which is called the carapace and the bottom half of the shell is called the plastron. Both parts of the shell of the turtle is fused bones.The upper part of the turtle's shell has 50 bones or the ribs and the vertebrae. The bottom part of the turtle's shell has collar bone between the ribs. Inside the shell are a blood and nerve supply if the shell is injured it can result in a bleeding and pain result. All reptiles are vertebrates, and they have very scaly skin which keeps their body from drying out. They are vertebrates, and, unlike any other animals, are covered in scales. They are ectotherms or cold-blooded, and control their body temperature by finding or avoiding the sun's heat. Reptiles obtain their oxygen through lungs.

Obtaining Food
There are different ways that reptiles obtain food for different reptile animals. Reptiles rely on their strong senses to find food and trick predators. Reptiles also have a great camouflage to try and trick their predators. Reptiles could be Carnivores or herbivores. Lizards, for an example, such as Chameleons, can move their two eyes so that one is looking at one direction and another is looking at another direction. Lizards could either be carnivores(eat meat) or herbivores(eat plants). Carnivore lizards mostly eat crickets, cockroaches, and earthworms. Herbivore lizards eat like a “salad mixture” of vegetables and leafy greens. Also snakes could be carnivores and herbivores. Snakes strike with hollow fangs that inject venom to the prey. The prey quickly reacts to the fast-acting venom. Reptiles taste and smell using an organ in the top of the mouth called the Jacobson’s organ—a small cavity lined with sense detectors that recognize chemical changes in and around the mouth. This sense organ helps the animal find prey, mates, and generally get information about its surroundings.

Reproduction
Reptiles are bisexual and produce two ways. All reptiles reproduce on land. Even reptiles that live in water come to land to reproduce. Reptiles can be egg layers or live bearers. All turtles, tortoises, crocodillians, snakes, and some lizards (Iguanas, Water dragons, Geckos, Veiled Chameleons, Panther chameleons, and monitors) reproduce by eggs. Other lizards (Solomon Island, Blue-tongue, and the Shingle-backed skink), some chameleon (Jackson’s chameleon), and some snakes. Turtles even tough they live in water reproduce on land because there young have a better chance of surviving by berth on land rather than water. Most reptiles lay amniotic eggs covered with leathery or calcareous shells. Reptiles eggs are covered by a much more water-proof shell then amphibian eggs. As a result, reptile eggs must be fertilized inside the mother before they are laid. Egg Layers: Females do not need the male to be near by to lay eggs. They lay their eggs in damp warm places. They then let the sun hatch the eggs. Baby Reptiles: Once reptiles are born they do not go through __metamorphosis__. Baby reptiles are very similar to adults, they are just smaller.

Movement
As lizards are not able to lift their body up to the limbs, they have to crawl using the help of limbs and tail. The snakes have three different ways of moving on land: lateral undulating, straight crawling, and side winding. Reptiles are also ectotherms, cold blooded, which means they need sun to move. Reptiles usually move very slowly so they have very strong muscles.

[[image:7salemanimalkingdom:snake-venom.gif width="250" height="252" align="left" caption="snake-venom.gif"]]Adaptations
Reptiles have thick skin that minimizes water loss and when your in the desert you need as much water as you can get. Smaller lizards try to avoid their predators by hiding, blending in, or running away. Reptiles that have round pupils are active during the day and can probably see in color. Reptiles that have slot-like pupils are usually hunting during the night and see in black and white. Crocodiles, snakes, lizards, and turtles are all reptiles. Most reptiles live on land, and most lay eggs. . During the hot seasons they spend most of their time moving around, looking for shady areas. Some lizards have longer legs, which makes it better because their legs don’t absorb much heat. When the colder season’s hit, they climb on rocks that are heated so they can raise their body temperature. Reptiles are ectotherms, cold-blooded and need sunlight. Few reptiles go through hibernation. They go to sleep during the hot weather. Before this time, they eat large amounts of food so that a layer of fat could form throughout their bodies. They utilize their stored fat that they obtain during the cooler season to survive.

Importance to Humans
Reptiles play a critical role in ecosystems everywhere except in frozen regions. They play an important role in the food chain and they help humans by controlling insect populations. Even though they are important to the world people still kill some of them and some of the species start to die out. People still use their skin and use their meat and other parts of their body to use for themselves and their personal gain. Reptiles are not always good for humans, they carry a lot of diseases that can make us really sick.About 3% of houses in the United States own at least one reptile. Reptiles, including turtles, lizards, and snakes, can carry germs that make people sick. The biggest one is salmonellosis. About 70,000 people get salmonellosis from contact with reptiles in the United States each year.

//Crocodilia (Alligators and Crocodiles)//
Crocodiles are very fast over short distances, they are also fast out of water to. They have extremely powerful jaws capable of biting down with incredible force. They have by far the strongest bite of any animal. The crocodile’s bite force is more than 5,000 pounds per square inch. Crocodiles have thin, pointed snouts and show most of their teeth when their jaw is closed. Alligator Facts: Alligators in the wild are believed to live 35 - 50 years. In captivity their lifespan may be longer, perhaps 60-80 years. Currently, there are no scientific methods getting an alligators age while it is alive. Although the tail of the alligator is considered the prime cut, all the meat of the alligator is edible. Alligators can run at speeds of up to 20 miles per hour. However that speed can only be used for a very short distance. Alligators have broad, rounded snouts and show few teeth when their jaw is closed.

//Squamata (Lizards and Snakes)//
There is one thing that separates lizards from all other reptiles. When a predator bites a lizard's tail, it will fall off for defense. In about one to two weeks there will be a new tail. In the colder seasons lizards lay on rocks to heat themselves up. One of the main snakes is the Rattlesnake. There are about 50 species of Rattlesnakes on the Earth. Rattlesnakes eat rodents, and other small animals. The rattle is composed of a series of hollow nested beads which are modified scales from the scale tip. They mostly mate in the spring, and give live birth instead of eggs. Lizards are reptiles that often are four-legged with scaly skin. They have external ears and most have movable eye lids. Most lizards are good climbers or fast sprinters. They are mostly harmless to humans, but the giant lizards could pose a threat of death.

//Testudines (Turtles)//
One thing that makes turtles different than other reptiles is that it has a shell. Turtle Facts
 * They have been on the Earth for more than 200 million years.
 * They have evolved before mammals, birds, snakes, crocodiles, and even lizards.
 * Most turtle shells are made of 60 bones linked together.