Let us know the main orders in which the class of reptiles is divided.
Are the turtles, the jabutis and the tortoises. They have the body covered by two carapaces: the dorsal carapace at the top of the body and the plastron at the bottom. These two carapaces are welded together. There are openings only for the exit of the neck, forelimbs and hindquarters and tail.
Turtles are aquatic and can live in fresh or saltwater; its legs are shaped like fins, which makes it easier to get around in the water. The jabutis are terrestrial and their fingers are thick. Tortoises live in freshwater and their fingers are linked by a membrane that aids in swimming.
These animals have no teeth. The mouth has a horny beak.
They are the crocodiles and the alligators. Large aquatic reptiles, crocodilians have elongated bodies and covered with corneal plates. They have four limbs, which are used for terrestrial and aquatic locomotion.
The alligator has a broader, rounder head than crocodilians, and when it closes its mouth, its teeth do not appear. Already the crocodile has the narrow head and even with the mouth closed, some teeth are visible.
Alligators and crocodiles inhabit tropical regions, usually on the banks of rivers.
In Brazil there are only alligators. They are found in the Amazon and Mato Grosso Pantanal.
They are the lizards and the snakes (these most commonly called snakes). These animals have their skin covered by scales and are divided into two smaller groups: lacerticles and ofids.
Lacertilles - They include lizards, chameleons and geckos, long-bodied reptiles with their heads short and joined by a small neck. They have four limbs, the anterior ones being shorter than the posterior ones.
Ophids - They include snakes or snakes, reptiles that have no legs. The vast majority of these animals have poison-producing glands. A snake is venomous when its teeth are capable of inoculating poison into the animals it attacks. The teeth have a channel or groove that communicates with the venom producing glands. At the moment of the bite, the poison seeps through this channel and is inoculated into the prey's body.
The reproductive system of reptiles was an important factor of adaptation of these animals to the terrestrial environment. Reptiles make the internal fertilization: Male introduces sperm into female's body.
Most are oviparousthat is, the female lays eggs, from which the chicks hatch. These eggs have a hard, consistent shell like leather. Eggs develop in a low humidity environment.
Internal fertilization and shell eggs represent a milestone in the evolution of vertebrates, as they prevented the death of gametes and embryos due to dehydration. Thus, in relation to reproduction, reptiles became water independent. The sea turtle and many other aquatic reptiles lay their eggs on land. They are covered with sand and warmed by the heat of the sun.
The egg is rich in calf - the substance that nourishes the embryo - and is able to retain moisture. In the shell there are pores, small holes that allow oxygen to enter the air and carbon dioxide to escape, that is, the exchange of gases. This helps keep the embryo alive.
Most reptiles do not need to take care of their eggs and young. Puppies when "ready" come out of the shell using their own resources. However, both alligator and crocodile are very careful with eggs and young. The female lays eggs in the nest and stays close until the birth of the young, which are carried in the mouth to the water, where they stay with the mother. Some even stay with their mother for more than three years.
There are also reptiles in whose eggs, already at the time of laying, there are formed chicks. The eggs are held with the embryo in a channel in the female's body as they develop, as with some snakes. By the time the eggs leave the female's body, the chicks inside them are already formed. The shell of these eggs is very thin, like a membrane, allowing the hatchlings to leave right after laying. These animals are classified as ovoviviparous. There are also some viviparous reptiles that produce ready-made puppies without having developed into eggs, such as certain species of lizards.