Reptiles are vertebrate animals that belong to the Animalia Kingdom, Phylum Chordata and Reptilia Class.
In evolutionary history, reptiles were the first vertebrate animals to conquer the terrestrial environment.
They are reptile examplesAttractions: turtle, tortoise, tortoise, snake, snake, alligator, crocodile, chameleon, iguana and lizard.
The reptile group is quite diverse
Features
Learn about the main characteristics of the reptile group:
Anatomy
crocodile anatomy
The body of reptiles is formed by the head, neck, trunk and tail.
They have two pairs of locomotor limbs, each with five toes ending in claws and legs reduced in some lizards but absent in others, such as snakes.
They can be crawling or swimming animals, such as sea turtles that have paddle-shaped paws.
The skin is dry and resistant, covered by scales of epidermal origin, which makes it keratinized and practically impermeable.
However, some animals, such as turtles and tortoises, can also have bone plates of dermal origin.
Body temperature
Reptiles are pecilothermic animals, that is, they are incapable of maintaining their body temperature constant. Thus, they need the heat of the environment to regulate body temperature.
This condition limits the location of their habitats to the tropics and subtropics of the planet, where temperatures favor their metabolism. Therefore, we do not find reptiles in Antarctica.
reproduction
Most reptiles are oviparous
Most reptiles are oviparous. Only some snakes and lizards are ovoviviparous.
They present internal fertilization, where the male introduces the sperm inside the female's body.
Embryo development takes place inside eggs, which are covered with horny or calcareous shells.
This feature protects the embryo from desiccation, which is important for conquering the terrestrial environment.
The egg has the following embryonic attachments: amnion, chorion, yolk sac and allantois.
When puppies are born, they resemble adults, as development is straightforward.
Digestive system and food
The digestive system is complete. They have mouth, pharynx, esophagus, stomach, intestine and cloaca. In addition, they have liver and pancreas.
Most reptiles are carnivores. A few species are herbivores and omnivorous.
Some reptiles, such as alligators and matamatá, are predatory animals and occupy the top of the food chain.
Circulatory system
Circulation is closed, double and complete.
The heart of snakes and turtles has two atria and an incompletely separated ventricle. While crocodilians have two well-defined atria and two ventricles.
Respiratory system
reptiles present lung breathing. The lungs have pulmonary alveoli, making gas exchange efficient.
Sensory System
The reptiles' olfactory organ allows them to taste and smell, and most reptiles are able to hear sounds.
Vision is not privileged, but the eyes have lids and a nictitating membrane to protect them when submerged.
When they are on land, they are hydrated by lacrimal glands, hence the expression “crocodile tears”, since those animals often “cry”.
Snakes have the loreal pit, a hole between the eye and the nostril with a thermo-reception function.
Also read about:
- Strings
- Vertebrate animals
- Animal Kingdom
groups
There are more than 7000 known species and subdivided into four orders:
Crocodile Order
Crocodile
Crocodilians represent most of the reptiles that currently exist.
The main characteristics of crocodilians are:
- Body covered by horny plates.
- Presence of four short legs and a tail.
- Big, sharp teeth.
- Heart with four completely separate cavities.
Rhynchocephalia Order
Tuatara, an endangered species
The order Rhynchocephalia is the most primitive reptile group. Therefore, the tuataras are the only living representatives of the order. They are found in New Zealand and can inhabit cold environments.
They are carnivorous animals, their teeth are fused to the jaw. Individuals of tuatara can reach up to 100 years of age.
Squamata Order
The snake is representative of the snake group
Also known as scales, as they have a body covered with scales. They are represented by snakes and lizards.
The main characteristics of the order Squamata are:
- Divided into Lacertílios (lizards) and Ophids (snakes).
- Lizards have four legs and snakes are without limbs.
- Some snake species are venomous animals.
Testudinate Order
Amazon turtle
Also called turtles, are represented by turtles, tortoises and tortoises. Turtles live in fresh and salt water environment. Tortoises are found in fresh water and tortoises on dry land.
The main characteristics of turtles are:
- Presence of bone armor (hull or carapace), which provides protection to the body against mechanical shocks and predator attacks.
- Absence of teeth and presence of a beak with horny blades, allowing to capture and cut food.
Learn more about Leather turtle.
Curiosities
- Dinosaurs, belonging to the superorder Dinosauria, belonged to the reptile class.
- Brazil is the fourth country in the world with the largest number of reptile species.
- Herpetology is the branch of biology that studies reptiles.
Also read about the History of Dinosaurs.
