Vertebrata(Reptilia)

Reptilia

Characteristics

Cold-Blooded animalsCold-blooded creatures take on the temperature of their

surroundings. They are hot when their environment is hot and cold when their environment is cold. In hot environments, cold-blooded animals can have blood that is much warmer than warm-blooded

animals.

Heart Many reptiles have a three-chambered heart consisting of two atria, one variably partitioned ventricle, and two aortas that lead to the systemic circulation. The degree of mixing of oxygenated and deoxygenated blood in the three-chambered heart varies depending on the species and physiological state. Under different conditions, deoxygenated blood can be shunted back to the body or oxygenated blood can be shunted back to the lungs.

Exception: Crocodile- Four-chambered heart!

Respiration All reptiles respire through lungs. The lungs of reptiles are large, and they are often divided internally into several chambers. The lining of the lungs may be folded into numerous small sacs called alveoli. Alveoli greatly increase the internal surface area of the lungs, thus increasing the amount of oxygen that can be absorbed. In most snakes, only the right lung actively functions. It is elongated and may be half as long as the body. The left lung is either reduced to a small nonfunctional sac or absent entirely.

HabitatThey are terrestrial or aquatic animals.

Skin

1)Water-Resistant-

Reptilian skin is covered in a horny epidermis, making it watertight and enabling reptiles to live on dry land, in contrast to amphibians.

2) In some animals, their skin is modified to Spines for Protection.

3)Shedding- They shed their skin

Defense Mechanisms

• 1) Camouflage- Reptiles tend to avoid confrontation through camouflage. Two major groups of reptile predators are birds and other reptiles, both of which have well developed colour vision. Thus the skins of many reptiles have cryptic colouration of plain or mottled gray, green, and brown to allow them to blend into the background of their natural environmentAided by the reptiles' capacity for remaining motionless for long periods, the camouflage of many snakes is so effective most people or domestic animals most typically are bitten because they accidentally step on them

A camouflaged Phelsuma deubia on a palm frond

Alternative defense in snakes

• Camouflage will not always fool a predator. When caught out, snake species will adopt different defensive tactics and use a complicated set of behaviors when attacked. Some will first elevate their head and spread out the skin of their neck in an effort to look large and threatening. Failure of this strategy may lead to other measures practiced particularly by cobras, vipers, and closely related species, who use venom to attack. The venom is modified saliva, delivered through fangs from a venom gland.

Defense in crocodiliansWhen a crocodilian is concerned about its safety, it will gape to expose the teeth and yellow tongue. If this doesn't work, the crocodilian gets a little more agitated and typically begins to make hissing sounds. After this, the crocodilian will start to change its posture dramatically to make itself look more intimidating. The body is inflated to increase apparent size. If absolutely necessary it may decide to attack an enemy.

Shedding and regenerating tails

• Geckos, skinks, and other lizards that are captured by the tail will shed part of the tail structure through a process called autotomy and thus be able to flee. The detached tail will continue to wiggle, creating a deceptive sense of continued struggle and distracting the predator's attention from the fleeing prey animal. The detached tails of leopard geckos can wiggle for up to 20 minutes.

• Reptiles capable of shedding tails can partially regenerate them over a period of weeks. The new section will however contain cartilage rather than bone, and will never grow to the same length at the original tail..

Our Team Members• Jerry George Jaimon (Leader)

• Shaun Saji

• Nithin Sam Cherian

• Kevin Babu

• Tobin Thanckachen

• Benjamin Jacob Reji

• Kyle Fernades

• Jobel Jose