The number of species of reptiles on earth. Class Reptiles, or Reptiles (Reptilia) General characteristics of the class. Based on their habitat, turtles are divided into

Reptiles, compared to amphibians, represent the next stage in the adaptation of vertebrates to life on land. They are the first true class of land vertebrates. They live mainly in regions with warm and hot climates. During the conquest of land, reptiles acquired a number of adaptations:

The body is divided into head, neck, torso, tail and five-fingered limbs.

The skin is dry, devoid of glands and covered with horny cover, protecting the body from drying out. The growth of the animal is accompanied by periodic molt.

Skeleton durable, ossified. The spine consists of five sections: cervical, thoracic, lumbar, sacral and caudal.

The shoulder and pelvic girdles of the limbs are strengthened and connected to the axial skeleton. The ribs and chest are developed. The musculature is more differentiated than in amphibians.

Developed cervical and intercostal muscles, subcutaneous muscles.The movements of the body parts are more varied and faster. The digestive tract is longer than that of amphibians and is more clearly differentiated into sections. Food is captured jaw tami, having numerous sharp teeth

. The walls of the mouth and esophagus are equipped with powerful muscles that push large portions of food into the stomach. At the border of the small and large intestines there is cecum, especially well developed in herbivorous land turtles. Respiratory system - lungs - have a large respiratory surface due to their cellular structure. Developed airways -.

trachea, bronchi, in which the air is moistened and does not dry out the lungs. Ventilation of the lungs occurs by changing the volume chest Heartthree-chamber, however, the ventricle has an incomplete longitudinal septum, which prevents complete mixing of arterial and venous blood. Most of the body of reptiles is supplied with mixed blood with a predominance of arterial blood, so the metabolic rate is higher than that of amphibians. However, reptiles, like fish and amphibians, are

poikilothermic (cold-blooded) ny) animals, Urine flows through the ureters into the cloaca, and from it into the bladder. In it, water is additionally sucked into the blood capillaries and returned to the body, after which urine is excreted. The end product of nitrogen metabolism, excreted in the urine, is

uric acid. The brain has a larger relative size than that of amphibians. The cerebral hemispheres of the forebrain with rudiments are better developed

bark and cerebellum. The forms of behavior of reptiles are more complex. Sense organs are better adapted to a terrestrial lifestyle. 10. Fertilization only internal. Reptiles lay eggs protected from drying out by a leathery or shell membrane. on the land.

The embryo in the egg develops in a watery shell. Development .

direct. Features of the structure and life processes

Let's look at the structure of the main organs of reptiles using the example

spinning lizards.

The lizard's body is divided into head, torso and tail. In the trunk section the neck is well defined. The entire body is covered with horny scales, and the head and belly are covered with large scutes. The limbs of the lizard are well developed and armed with five fingers with claws.

The humerus and femur bones are parallel to the surface of the ground, causing the body to sag and touch the ground (hence the name of the class). The cervical spine consists of eight vertebrae, the first of which is movably connected to both the skull and the second vertebra, which provides the head with greater freedom of movement. The vertebrae of the thoracolumbar region bear ribs, some of which are connected to the sternum, resulting in the formation of the rib cage. The sacral vertebrae provide a stronger connection to the pelvic bones than in amphibians. are represented by pelvic kidneys, in which the total filtration area of the glomeruli is small, while the length of the tubules is significant. This promotes intensive reabsorption of water filtered by the glomeruli into the blood capillaries. Consequently, the excretion of waste products in reptiles occurs with minimal water loss. In them, like in terrestrial arthropods, the end product of excretion is uric acid, which requires a small amount of water to be excreted from the body. Urine is collected through the ureters into the cloaca, and from it into the bladder, from which it is excreted as a suspension of small crystals.

Brain Reptiles, compared to those of amphibians, have a better developed cerebellum and cerebral hemispheres of the forebrain, the surface of which has the rudiments of the cortex. This causes various and more complex forms of adaptive behavior.

Sense organs more consistent with a terrestrial way of life. The eyes are protected by movable eyelids (upper and lower) and a nictitating membrane. Focusing of vision is achieved both by moving the lens relative to the retina and by changing its curvature. Some diurnal species have color vision. Lizards have a well-developed parietal eye, a light-sensitive organ located on the crown.

Rice. 41. Lizard brain: I - top; II - from below; III - side; 1 - forebrain; 2 - striatum; 3 - midbrain; 4 - cerebellum; 5 - medulla oblongata; 6 - funnel; 6" - pituitary gland; 7 - chiasm; 8 - olfactory lobe; 9 - pineal gland.

Hearing organ consists of the middle and inner ear. The sense of smell is better developed than in amphibians.

Some species of snakes have a thermal sense organ (between the nostrils and the eye), which allows them to sense the heat emanating from their prey at a distance. This makes it possible for snakes to hunt warm-blooded animals without seeing them.

In reptiles, fertilization is internal. They reproduce by laying eggs or ovoviviparity. The eggs are relatively large and rich in nutrients, which ensures direct development of the embryo without intermediate larval stages. The eggs are protected from drying out by protective shells (leathery or shell). The embryo in the egg develops in a cavity filled with fluid, which contributes to the proper formation of its organs.

Diversity and importance of reptiles

Modern reptiles are only small remnants of a rich and diverse world of animals that inhabited not only all the land, but also all the seas of the planet in the Mesozoic era. Currently, the class Reptiles includes more than 7 thousand species, united in several orders, among which the most numerous are Scaly, Crocodiles, Turtles and Beaked.

Order Scaly ( Sguamata ) – the largest group of reptiles (approximately 6.5 thousand species). They are characterized by the presence of horny scales in their integument.

The sandy lizard lives in the middle zone of the CIS, the viviparous lizard is common to the north, and geckos, agamas and the most common live in the southern regions. large lizard – gray monitor lizard(up to 2 m long). Thanks to its well-developed limbs, the monitor lizard runs quickly, its body raised high above the ground. Monitor lizards are widespread in Africa, South Asia, the Malay Archipelago and Australia, as well as in the sandy deserts of Turkmenistan and Uzbekistan.

Snakes are legless, scaly animals with a long cylindrical body, using the wavy curves of which they move. They do not have movable eyelids. Prey is swallowed whole thanks to a widely extensible mouth (the lower jaws are suspended on extensible ligaments). The teeth are sharp and directed backwards. When attacking a victim Poisonous snakes They push their teeth forward from the oral cavity and with their help introduce the secretion of poisonous glands into the body of the prey. The sternum is missing. The ribs are free and extremely mobile. The middle ear is simplified, the eardrum is absent. Distributed in all parts of the world, but numerically predominant in hot countries. Non-venomous snakes are widely known - snakes, boa constrictors, and poisonous ones - viper, viper, rattlesnake, sand faff etc. Snake venom is used to prepare medicines.

Squad Crocodiles ( Crocodylia ) represented by large (up to 6 m long), the most highly organized reptiles, adapted to a semi-aquatic lifestyle. They have a lizard-like, slightly flattened body, covered with horny scutes, with a laterally compressed tail and swimming membranes between the toes of the hind legs.

Rice. 42. Crocodiles: 1 - gharial; 2 - Nile crocodile; 3 - Chinese alligator

The teeth sit in cells (like in mammals).

They reproduce by laying eggs (10-100 eggs) covered with a calcareous shell. They become sexually mature at 8-10 years of age and live up to 80-100 years.

Known are the Nile crocodile (Africa), alligator (China, America), caiman (America), gharial (Hindustan, Burma). In some countries, crocodile meat is used in food, and the skin is a valuable raw material for the manufacture of haberdashery. Due to intensive fishing, the number of crocodiles has sharply decreased. Farms for their breeding have been created (USA, Cuba).

Turtle Squad ( Testudines ) unites reptiles that have a compact body enclosed in a durable bony shell into which the neck, head, limbs and tail can be retracted. The top of the bone shell is covered with horny plates or soft skin.

Rice. 43. Turtles: 1 - elephant turtle; 2 - steppe tortoise; 3 - marsh turtle; 4 - carriage; 5 - Ussuri soft-skinned turtle.

The jaws are devoid of teeth and have sharp horny edges. The vertebrae, except for the cervical and caudal sections, are fused to the dorsal part of the shell (as are the ribs). The breathing mechanism is associated with the movement of the neck and shoulders, which, moving out from under the shell, stretch the lungs. The metabolic rate is low. Capable of prolonged fasting. They live in humid tropics and hot deserts. In many countries, turtle meat and eggs are eaten. The horny plates of some turtle species are used to make crafts. Swamp turtle - lives in weakly flowing water bodies and feeds on a variety of small aquatic and terrestrial animals.

Lives in the Galapagos Islands elephant turtle. The huge shell can be up to 110 cm long and up to 60 cm high. Thick and powerful columnar legs support the heavy body. The mass of adult specimens is about 100 kg, and individual giants weigh up to 400 kg.

The only type of modern Beakheads ( Rhynchocephalia ) – tuateria has many extremely primitive features and is preserved only in New Zealand and the surrounding islands.

Rice. 44. Hatteria.

Hatteria looks very much like a lizard with a massive body, big head and five-fingered limbs. A low ridge of triangular vertical plates stretches from the back of the head along the back and tail. The hatteria is painted in a dull olive green color, with small and larger yellow spots on the sides of the body and limbs.

The pupils of the large eyes, located on the sides of the head, are in the form of a vertical slit. The tuateria does not have eardrums; the middle ear cavity is filled with adipose tissue.

The body of adult males is up to 60 cm long, weighing 800 g. Females are almost twice as small as males. Hatteria reaches maturity only at 20 years of age. Life expectancy is also long: in captivity, tuataria lived for more than 70 years.

The main food of the tuateria is various invertebrates, especially insects, in particular beetles and large wingless grasshoppers, as well as spiders, worms, mollusks, sometimes lizards, frogs, and bird eggs. The hatteria swallows its prey whole.

The tuateria moves slowly, while hardly raising its belly above the substrate. However, when hunting or in a frightened state, it rises to its feet and moves quickly. In addition, she is a good swimmer and willingly goes into the water.

Origin of reptiles. Reptiles have been known since the end Carboniferous period Paleozoic era. They reached their heyday in the Mesozoic era, by the end of which they were replaced by birds and mammals. The ancestors of modern reptiles are considered to be primitive Devonian amphibians - stegocephalians, which gave rise to cotilosaurs - ancient reptiles.

The flourishing of ancient reptiles in the Mesozoic era was facilitated by a warm climate, an abundance of food both on land and in water, as well as a lack of competitors. They inhabited a terrestrial environment dominated by giant dinosaurs, reaching a length of 30 m. Among them were both herbivores and predators. The aquatic environment was dominated by fish-like lizards - ichthyosaurs (8 - 12 m). A peculiar group consisted of pterosaur lizards, which could fly thanks to a large leathery membrane stretched between the fore and hind limbs.

The extinction of ancient reptiles is associated with the cooling of the climate at the end of the Mesozoic and their inability to maintain a constant body temperature. The ensuing decline in vital processes in reptiles led to their weakening competition with the emerging and rapidly progressing mammals.

Control questions:

What is the peculiarity of the organization of reptiles?

What orders are included in the class of reptiles?

What features of the skeletal structure are inherent in reptiles?

What is autotomy in reptiles?

What reproductive features are characteristic of reptiles?

The class of vertebrates that occupy an intermediate position between amphibians and mammals is called reptiles. They are more similar to birds. The following animals belong to this class according to the list:

crocodiles;
turtles;
snakes;
lizards;
dinosaurs ( fossil form animals of the Mesozoic era).

General characteristics of reptiles

Like amphibians, reptiles are cold-blooded creatures. In other words, their body temperature is determined by their surroundings. To some extent, reptiles are able to regulate their temperature by covering themselves against hypothermia. For example, in winter time animals hibernate during the year, and during extreme heat They begin hunting at night.

Reptiles have tough skin covered with scales. The main task which is to protect the body from drying out. For example, in turtles the upper protection is provided by a durable shell, crocodiles have hard plates of bone origin on their head and back.

Reptiles breathe only through the lungs. In some animal species the lungs are the same size and development, while in others, such as snakes and lizards, the right lung has larger size and is located throughout the body cavity. Turtles have fixed ribs due to their shell, so the ventilation of the body is organized in a different way. Air enters the lungs during rocking movements of the front legs or during intense swallowing.

The bony skeleton of reptiles is quite well developed. The number and shape of ribs depends on the specific species, but all representatives of the class have them. Almost all turtles have fused bony plates of the shell and spine. Snakes have ribs designed for active crawling. In lizards, the ribs serve to support fan-shaped membranes for gliding in the air.

Most reptiles have short tongue, which cannot stick out. Snakes and lizards have a long tongue, divided in two, which can extend far from the mouth. For this species of animal these are the most important sense organs.

To protect against environment Small reptiles have original coloring. Turtles are reliably protected by a dense shell. Some snakes are poisonous.

In terms of reproductive organs, reptiles are similar to birds. As a rule, reptiles are oviparous animals. But in some species, eggs remain inside in the oviduct until hatching. This type includes some species of lizards and vipers.

Classification of reptiles and their distribution

Modern reptiles are divided into four groups:

turtles (about 300 species);
crocodiles (25 species);
scaly (about 5,500 species of lizards and snakes);
tuatara (tuatara).

The last order belongs to the only representative of beaked animals among reptiles.

Reptiles distributed throughout the world. The greatest numbers are seen in warm areas. In regions with cold climates and lack of woody vegetation, reptiles are practically not found. Representatives of this class live on land, in water (fresh and salty) and in the air.

Ancient reptile fossils

Reptiles have been known since the Carboniferous period. They reached their largest sizes in the Permian and Triassic periods. At the same time, there was an increased reproduction of animals that populated more and more new territories. IN Mesozoic era the dominance of reptiles was overwhelming, both on land and in water. It is not for nothing that this period was called the Age of Reptiles.

Turtles

One of the most famous species of reptiles are turtles. There are both marine and land representatives of animals. The species is distributed throughout the world. Animals are also allowed keep at home. The most ancient representatives of turtles were discovered 200 million years ago. Scientists believe that they descended from a primitive species of cotylosaurs. Turtles are practically harmless animals, they are not dangerous to people.

Animals of this species have a shell of a bone structure. On the outside, it is formed by numerous individual elements of horny tissue, which are connected by plates. For breathing land turtles The lungs function well. Aquatic representatives of the class breathe using the mucous membrane of the pharynx. main feature these animals - longevity. Average age Turtles have a longer lifespan than any other reptile.

Crocodiles

Animals are among the most dangerous species reptiles. The origin of crocodiles is associated with ancient reptiles, the size of which exceeded 15 meters in length. Scientists were able to find the remains of ancient crocodiles on all continents of the globe. Modern representatives of this class have more conventional sizes. But among reptiles they still remain the largest species.

Almost all the time crocodiles are in the water. Only the ears, nose and eyes of the animal appear on the surface. Crocodiles swim using webbed tails and paws. But at great depths, only single representatives of the class can exist - the comb species. Crocodiles' nests are located on land. In some cases, they also crawl out of the water to warm themselves.

Reptiles have a strong, powerful tail and are also characterized by high speed travel by land. Therefore, crocodiles are extremely dangerous to humans. A sudden sudden burst can take people by surprise. Most dangerous representatives Alligators are considered crocodiles.

Chameleons

This type of lizard is known to almost everyone. Reptiles are known for their unique coloration, which serves as a camouflage feature. An animal's skin can change color depending on environmental conditions. Chameleons live in trees. Some people keep these cute creatures at home.

Reptiles are quite finicky to care for. They need a spacious terrarium, which is equipped with special lamps. You will need wood, a small pond, heated floors and excellent ventilation. Chameleons feed on insects. Therefore, the owners will also have to take care of their availability.

Iguanas

Nowadays everything appears more lovers pets - iguanas. This representative of lizards also requires special care. Iguanas must be kept in a special terrarium that can maintain a certain temperature regime. For food, domestic iguanas prefer fresh fruits and vegetables, as well as greens. With good care and optimal living conditions, lizards at home can grow quite large. Maximum iguana weight - 5 kg. It is difficult to keep such a pet at home; it will require a large financial investment, as well as significant labor costs.

Iguanas are one of those rare species reptiles that molt. Most reptiles experience this period in two days, but in iguanas it lasts for several weeks.

Monitor lizards

There are about 70 species of monitor lizards. They live in different territories. The size of the animals is very impressive. Short-tailed monitor lizards have a length of about 20 cm, while other representatives have a much longer length (about 1 meter). The most large monitor lizards are considered Komodo species. Their dimensions reach three meters in length, and their weight is 1500 kg. It’s not for nothing that such animals are called modern dinosaurs.

Monitor lizards are covered with large scales. They have strong paws with a tenacious grip and powerful a long tail . The animal's tongue is also large in size; at the end it is divided in half. Lizards can only smell with their tongue. The color of animals is dominated by gray and brown shades. Young representatives of the class are often found with spotted or striped scales. Monitor lizards live in regions with warm climate. Most common in Australia, Africa and south asia. Depending on their habitat, monitor lizards are divided into two types. The first of them lives in a desert area with dry trees and shrubs. And the second is located closer to tropical forests and reservoirs. Some representatives of monitor lizards live on tree branches.

Geckos

Unique representatives of reptiles that are able to stick to any surface, even the smoothest. Geckos can climb smooth glass walls, hang from ceilings, and many other interesting things. The lizard is able to stay on the surface with just one paw.

Snakes

These are famous representatives of reptiles. The main difference from other species is the body shape. Snakes have a long body, but do not have paired limbs, eyelids or an external auditory canal. Some of these characteristics are present in individual lizard species, but collectively such characteristics are only observed in snakes.

Zmeinoye the body consists of three elements:

head;
body;
tail.

Some representatives retained rudimentary forms of limbs. A large number of species of snakes are poisonous. They have grooved or channeled teeth that contain venom. This dangerous liquid comes from the animal's salivary glands. All internal organs snakes differ from standard indicators. They have an oblong shape. Animals do not have a bladder. There is before our eyes cornea, which was formed from fused eyelids. The snakes that lead daytime look life, have a transverse pupil, and night snakes are characterized vertical arrangement pupil Because Since animals do not have an auditory canal, they can only hear loud sounds.

Snakes

These are representatives of one of the varieties of snakes. Their main feature is that they are not poisonous. Snakes have bright scales with a large ribbed surface. Animals are common near water bodies. Amphibians and fish serve as food for them. Sometimes snakes manage to catch a bird or small mammal. Such snakes do not kill their prey; they swallow it whole.

If a snake senses danger, it pretends to be dead. And when she is attacked, a liquid with extreme unpleasant smell. Snakes breed on plant soils covered with damp moss or natural debris.

The list of modern reptiles can be continued for a very long time. All representatives of the class have certain similarities characteristic of this type of animal, as well as clear differences. Such animals are of great interest to scientists and hobbyists from all over the world. Their unique features can tell you a lot.

Reptiles

REPTIENTS -theirs; pl. Zool. The name of the class of vertebrates, including snakes, lizards, turtles, crocodiles; reptiles.

reptiles

(reptiles), class of vertebrates. Characterized by mixed blood circulation; They breathe through their lungs, their body temperature is not constant, and most of the skin is covered with horny scales or scutes (protection from drying out). Modern reptiles include: turtles, crocodiles, beaked reptiles (hatteria) and scaly reptiles (lizards, amphisbaenas and snakes). Over 8000 species, mainly in hot and warm belts. Most live on land, some in the seas. They feed mainly on animal food. They lay eggs, some are ovoviviparous and viviparous. The meat and eggs of some reptiles are eaten. Various products are made from the skin of snakes, lizards and crocodiles. The numbers of many species (especially turtles, snakes and crocodiles) are declining sharply. About 150 species and subspecies of reptiles are in the IUCN Red List. The most ancient reptiles appeared in the Middle Carboniferous. Having reached their heyday and enormous diversity in the Mesozoic (dinosaurs, pterosaurs, etc.), many groups completely died out by the end of the Mesozoic. Herpetology deals with the study of reptiles.

REPTIENTS

REPTILES (reptiles; Reptilia), class of vertebrates (cm. VERTEBRATES); distributed on all continents except Antarctica. Reptiles are characterized by mixed blood circulation; they breathe through their lungs, their body temperature is variable, and most of their skin is covered with horny scales or scutes (protection from drying out). Currently, there are about 7-8 thousand reptiles, divided into 4 orders. These are turtles (230 species); scaly, the most numerous (about 6,500 species), which include snakes and lizards; crocodiles (22 species) and beaked crocodiles, represented by a single species - tuateria (cm. HATTERIA), living in New Zealand.
Reptiles live mainly in hot and warm climate zones. (cm. Reptiles are the oldest animals that first appeared in the Middle Carboniferous. Compared to amphibians, they represent the next stage in the adaptation of vertebrates to life on land. They are the first true land vertebrates, reproducing on land by eggs and breathing only through their lungs. Reaching in the Mesozoic MESOZOIC ERA) (cm. flourishing and enormous diversity (dinosaurs DINOSAURS) (cm., pterosaurs PTEROSAURS) (cm. etc.), many groups became completely extinct by the end of the Mesozoic. Herpetology deals with the study of reptiles.
The body of reptiles is covered with scales, scutes or other horny formations and, in most species, lacks skin glands. They breathe atmospheric air. Body temperature is not constant, it depends on the temperature of the environment, and the activity of animals also depends on it. Crocodiles and many turtles live in fresh water, some snakes and turtles live in the sea.
Most species reproduce by laying eggs, but there are also ovoviviparous and viviparous species. The eggs are enclosed in a hard calcareous (in turtles and crocodiles) or parchment-like (in lizards and snakes) shell that protects them from drying out. The incubation period is from 1–2 months to a year or more (for tuateria). They rarely care for their offspring. The overwhelming majority of reptiles are predatory or insectivorous animals. Some lizards (agamas and iguanas) are omnivores; land turtles feed primarily on plants.
In the 20th century, the number of certain groups of reptiles, especially turtles, snakes and crocodiles, sharply decreased due to the use of meat for food, skin and shells for the manufacture of various products, and the use of snake venom in medical purposes. To restore and preserve the number of reptiles, they are bred in captivity, breeding sites are protected, and fishing is prohibited.
Lizards, snakes, turtles and even crocodiles are kept in captivity. The soil in the terrarium (earth, sand, peat) and its moisture must correspond to the living conditions of animals in nature. For all animals, including desert dwellers, there must be clean water in the terrarium (in drinking bowls, ditches, pools). All reptiles need shelter; many species require humidity chambers. For normal life, they imitate natural temperature changes, length daylight hours. For this purpose, incandescent lamps and other devices are used, with the help of which during the day they heat the area familiar to the animals, which can accommodate all the inhabitants of the terrarium. At night the heater is turned off, which simulates a nighttime drop in temperature.
In the cold season, for several weeks or months, the length of daylight hours is reduced and the temperature of the housing is reduced. For animals living in nature in conditions temperate climate, imitate the wintering condition. The food is live frogs, small rodents, birds, worms, various insects, as well as carcasses of small animals, prepared in advance and frozen. Fish, squid, shrimp, snails, and less often meat are also used in feeding, and vitamins are also given. It is advisable to diversify animal food for carnivorous reptiles with plant food, and for herbivorous reptiles it is necessary to add animal food.
To obtain offspring in captivity, they practice various ways formation of breeding groups. The optimal option is considered to be 2–3 males per 1 female for turtles, 1–2 males per 3 females for lizards, and 2 males per 1 female for snakes. The female can be placed with a group of males or sequentially with several individual males only during the breeding season. Eggs or hatchlings are removed from the terrarium with adult animals. The eggs are kept in special incubators. The temperature and duration of incubation are different for different groups and species of reptiles.

encyclopedic Dictionary . 2009 .

See what “reptiles” are in other dictionaries:

Reptiles ... Wikipedia

REPETTLES, representatives of approximately 6,000 species of vertebrates distributed throughout the globe. Reptiles are poikilothermic (cold-blooded) animals. Most of them lay eggs rich in yolk on land. Some… … Scientific and technical encyclopedic dictionary

- (reptiles) class of vertebrates. Characterized by mixed blood circulation; They breathe through their lungs, their body temperature is variable, and most of the skin is covered with horny scales or scutes (protection from drying out). Modern reptiles include: ... ... Big Encyclopedic Dictionary

Reptiles (Reptilia), class of vertebrates. The most ancient P. cotylosaurs appeared in the Middle Carboniferous and still retained in their structure features characteristic of Paleozoic amphibians (stegocephalians). Subsequently, P. were divided into 2 chapters. trunk... ... Biological encyclopedic dictionary

Reptiles Dictionary of Russian synonyms. reptiles adj. reptiles Dictionary of Russian synonyms. Context 5.0 Informatics. 2012… Synonym dictionary

REPETTLES, theirs, units. ongoing, ongoing, cf. The class of vertebrates that move predominantly. crawling or dragging their belly along the ground (snakes, lizards, crocodiles, turtles), reptiles. Dictionary Ozhegova. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 … Ozhegov's Explanatory Dictionary

- (Reptilia) class of vertebrates. The skin is covered with horny scales or scutes, breathing is exclusively pulmonary, the blood temperature is variable, the heart is three or four chambered, the arterial blood flow mixes with the venous one either in the heart, or... ... Encyclopedia of Brockhaus and Efron

reptiles- reptiles, reptiles: they breathe only air; breed only on land; mixed circulation; Most skin is covered with horny scales; eat primarily animal food. turtles (land, freshwater, sea). hydromedusa... ... Ideographic Dictionary of the Russian Language

Reptiles or reptiles are the oldest class of true vertebrates that settled on land.

Reptiles include different kinds snakes, crocodiles, turtles and lizards.

They were the most major representatives dinosaurs that dominated the Earth 150 million years ago.

The animals are direct ancestors despite the fact that they now live in swamps - some of them could fly, and their elongated scales eventually turned into feathers.

Description

The name of the class comes from the word to creep - to move by crawling, dragging your stomach along the ground. This is true - reptiles have no limbs at all; in others they are located almost at the level of the spine.

Appearance

Unlike amphibians, which are wet and slippery to the touch, reptiles have always dry skin. This helps retain moisture inside the body, which is especially important for inhabitants of arid areas.

Reptiles description

Reptiles are endowed with perfectly protected skin from external influences, including the scorching sun; the skin is covered with scales. Snakes and lizards periodically molt, that is, shed the skin from which they grew, and then grow new skin.

Almost all animals of the class reptiles are colored in accordance with color scheme environment, so as not to become easy prey for predators, and so as not to be too noticeable to their victims.

The chameleon became famous for the fact that it can change color depending on many factors - temperature, humidity, thirst, emotional state.

Nutrition

Animals are not able to chew food, they can only tear it into pieces. And snakes generally swallow prey whole, and often the size of the victim exceeds the size of the snake itself.

Reptiles of our Planet

A snake can perform such a trick thanks to its ability to open its mouth very wide; its stomach can stretch to incredible sizes.

Habitat

Most reptiles live in warm regions - deserts, semi-deserts and tropical rainforests.

They can also be found in cooler natural areas, in deciduous and mixed forests, but much less often.

Unusual reptiles

This is explained by the fact that the body temperature of reptiles is practically no different from the ambient temperature. Therefore, reptiles living in cold areas have to warm up in the sun for a long time. IN warm time During the year they lead an active life, and in cold weather they hibernate.

Reproduction

Reptiles lay eggs in a hard protective shell and leave them in nests or simply bury them in the sand.

All of them except , don't care about future fate their cubs - having hatched from the eggs, they already lead an independent life. Some species of lizards and snakes are viviparous.

Red Book

Almost all species of reptiles are listed in the Red Book, some of them are on the verge of extinction.

Reptiles animals snakes photo

On the part of the governments of some countries, measures are being taken, special farms are being created for the reproduction of one or another species that is about to disappear. But this will not help much, since many species of reptiles have already been so exterminated by humans that it is not possible to restore them.

Lifespan

Due to the fact that all processes in the body of reptiles occur very slowly, their life expectancy is very high. Crocodiles live about 70 years, and turtles live more than 150.

Reptiles are an important part of the food chain - they feed on insects and small rodents and thereby regulate their quantity. The reptiles themselves serve as food for some.
Snake venom is the basis of many medicines.
Expensive shoes and accessories are made from crocodile and snake skin, and jewelry is made from shells.
For this purpose, reptiles are raised on special farms so as not to reduce their numbers in the wild.
The meat and eggs of crocodiles and turtles are eaten by residents of many tropical countries.

Scales on the skin of a lizard

The girdle of the forelimbs is similar to the girdle of amphibians, differing only in the stronger development of ossification. The forelimb of reptiles consists of the shoulder, forearm and hand. Posterior - from the thigh, lower leg and foot. Claws are located on the phalanges of the limbs.

Muscular system

The brain is located inside the skull. Row important features distinguishes the brain of reptiles from the brain of amphibians. They often talk about the so-called sauropsid type of brain, which is also inherent in birds, in contrast to the ichthyopsid type in fish and amphibians.

There are five sections of the reptile brain.

The forebrain consists of two cerebral hemispheres, from which the olfactory lobes extend. The surface of the cerebral hemispheres is absolutely smooth. In the medullary vault of the hemispheres, a primary vault is distinguished - the archipallium, which occupies most the roofs of the hemispheres, and the rudiments of the neopallium. The floor of the forebrain mainly consists of the striatum.
The diencephalon is located between the forebrain and midbrain. The parietal organ is located in its upper part, and the pituitary gland is located on the lower side. The bottom of the diencephalon is occupied by the optic nerves and their chiasm.
The midbrain is represented by two large anterior hills - the optic lobes, as well as small posterior hills. The visual cortex is more developed than in amphibians.
The cerebellum covers the anterior part of the medulla oblongata. It is larger compared to the cerebellum of amphibians.
The medulla oblongata forms a bend in the vertical plane, which is characteristic of all amniotes.

12 pairs of cranial nerves arise from the brain. In the spinal cord, the division into white and gray matter is more distinct than in amphibians. Segmental spinal nerves arise from the spinal cord to form the typical brachial and pelvic plexus. The autonomic nervous system (sympathetic and parasympathetic) is clearly expressed in the form of a chain of paired nerve ganglia.

Sense organs

Reptiles have five main sense organs:

The organ of vision, the eyes, are more complex than those of frogs: the sclera contains a ring of thin bone plates; a ridge extends from the back wall of the eyeball, protruding into the vitreous body; in the ciliary body, striated muscles are developed, which allows not only to move the lens, but also to change its shape, thus achieving focus during the process of accommodation. The organs of vision have adaptations to work in the air environment. The lacrimal glands protect the eye from drying out. The outer eyelids and nictitating membrane perform a protective function. In snakes and some lizards, the eyelids fuse to form a transparent membrane. The retina of the eye can contain both rods and cones. Nocturnal species have no cones. Most daytime species The range of color vision is shifted to the yellow-orange part of the spectrum. Vision is crucial among the sense organs of reptiles.
The olfactory organ is represented by the internal nostrils - choanae and the vomeronasal organ. Compared to the structure of amphibians, the choanae are located closer to the pharynx, which makes it possible to breathe freely while food is in the mouth. The sense of smell is better developed than that of amphibians, allowing many lizards to find food located under the surface of the sand at a depth of 6-8 cm.
The organ of taste is the taste buds, located mainly in the pharynx.
The thermal sensory organ is located on the facial fossa between the eye and nose on each side of the head. Especially developed in snakes. In pit snakes, thermolocators can even determine the direction of the source of thermal radiation.
The organ of hearing is close to the organ of hearing of frogs; it contains the inner and middle ear, equipped with a tympanic membrane, an auditory ossicle - the stirrup, and an eustachian tube. The role of hearing in the life of reptiles is relatively small; the hearing of snakes, which do not have eardrum and perceiving vibrations propagating along the ground or in water. Reptiles perceive sounds in the range of 20-6000 Hz, although most hear well only in the range of 60-200 Hz (for crocodiles 100-3000 Hz).
The sense of touch is clearly expressed, especially in turtles, which can feel even a light touch on the shell.

Respiratory system

Reptiles are characterized by suction-type breathing by expanding and contracting the chest with the help of intercostal and abdominal muscles. The air entering through the larynx enters the trachea - a long breathing tube, which at the end is divided into bronchi leading to the lungs. Like amphibians, the lungs of reptiles have a sac-like structure, although their internal structure is much more complex. The inner walls of the lung sacs have a folded cellular structure, which significantly increases the respiratory surface.

Since the body is covered with scales, reptiles do not have cutaneous respiration, and the lungs are the only respiratory organ.

Circulatory system

Circulatory system of reptiles

Like amphibians, most reptiles have a three-chambered heart, consisting of one ventricle and two atria. The ventricle is divided by an incomplete septum into two halves: upper and lower. With this design of the heart, a gradient (difference) in the amount of blood oxygen is established in the slit-like space around the incomplete ventricular septum. After the atria contract, arterial blood from the left atrium enters the upper half of the ventricle and displaces venous blood from the right ventricle into the lower half. Mixed blood appears in the right side of the ventricle. When the ventricle contracts, each portion of blood rushes to the nearest hole: arterial blood from the upper half - into the right aortic arch, venous blood from the lower half - into the pulmonary artery, and mixed blood from the right part of the ventricle - into the left aortic arch. Since it is the right aortic arch that carries blood to the brain, the brain receives the most oxygen-rich blood. In crocodiles, the septum completely divides the ventricle into two halves: the right - venous and the left - arterial, thus forming a four-chambered heart, almost like in mammals and birds

In contrast to the common arterial trunk of amphibians, reptiles have three independent vessels: the pulmonary artery, and the right and left aortic arches. Each aortic arch bends back around the esophagus, and when they meet each other, they unite to form the unpaired dorsal aorta. The dorsal aorta stretches back, sending arteries along the way to all organs. From the right arch of the aorta, extending from the left arterial ventricle, the right and left carotid arteries branch off with a common trunk, and both subclavian arteries, carrying blood to the forelimbs, branch off from the right arch.

A complete division into two independent circles of blood circulation in reptiles (including crocodiles) does not occur, since venous and arterial blood mix in the dorsal aorta.

Like fish and amphibians, all reptiles are cold-blooded animals.

Digestive system

Due to the variety of food available for nutrition, the digestive tract of reptiles is much more differentiated than that of amphibians.

Excretory system

The kidneys of reptiles differ significantly from the kidneys of fish and amphibians, which have to solve the problem of getting rid of a constant excess of water in the body. Instead of the trunk kidneys of amphibians (mesonephros), the kidneys of reptiles (metanephros) are located in the pelvic region on the ventral side of the cloaca and on its sides. The kidneys are connected to the cloaca through the ureters.

The thin-walled, stalk-shaped bladder is connected to the cloaca by a thin neck on its ventral side. In some reptiles the bladder is underdeveloped (crocodiles, snakes, some lizards).

Reproductive system

Reptiles are dioecious animals.

Men's reproductive system consists of a pair of testes that are located on the sides of the lumbar spine. A seminal canal extends from each testis, which flows into the Wolffian canal. With the appearance of the trunk bud in wolf reptiles, the canal in males acts only as a vas deferens and is completely absent in females. The Wolffian canal opens into the cloaca, forming the seminal vesicle.

Female reproductive system represented by ovaries, which are suspended on the mesentery to the dorsal side of the body cavity on the sides of the spine. The oviducts (Müllerian canals) are also suspended on the mesentery. The oviducts open into the anterior part of the body cavity with slit-like openings - funnels. The lower end of the oviduct opens into the lower part of the cloaca on its dorsal side.

Lifestyle

Development

Fertilization is internal.

Nutrition

Most reptiles are carnivores. Some (for example, agamas, iguanas) are characterized by a mixed diet. There are also almost exclusively herbivorous reptiles (land turtles).

Economic importance

The importance of reptiles for humans is relatively small. Crocodile skin, large snakes and lizards are used in the leather industry to make suitcases, belts, shoes, etc., however, these items are of an exclusive nature, being a luxury item. The meat of some turtles and eggs are eaten. Snake venom is used in medicine. Many snakes are useful in exterminating rodents, and lizards are useful in exterminating insects. Some species of reptiles are kept as pets.

Poisonous snakes pose a great danger to people, especially in tropical countries. Large crocodiles are dangerous to humans and cause damage to livestock. Many turtles harm fisheries.

Origin of reptiles

The first representatives of reptiles - cotylosaurs - have been known since the Middle Carboniferous. By the end of the period, animal-like reptiles appeared, which in the Permian period settled almost throughout the entire land, becoming the dominant group among reptiles. In the Mesozoic era, reptiles flourished, and the greatest diversity was observed among the representatives. The development of sea and river reservoirs is taking place, as well as airspace. In the Mesozoic, all groups of reptiles formed. Last group- snakes - formed in the Cretaceous period.

At the end Cretaceous period There is a sharp reduction in the number of reptile species. Unambiguously indicate the causes of extinction modern science can't yet.

Classification

There is a lot of uncertainty in the classification of reptiles, largely because most of them are extinct. Below is one of the possible options.

Subclass Anapsida ( Anapsida)
- Turtles ( Testudines or Chelonia)
- †Cotylosaurus ( Cotylosauria)
- †Seymuriomorpha ( Seymouriomorpha)
Subclass Proganosaurus ( Proganosauria)
- † Mesosaurs ( Mesosauria)
Subclass Ichthyopterygia ( Ichtyopterygia)
- †Ichthyosaurs ( Ichthyosauria)
Subclass Synaptosaurus ( Synaptosauria or Euryapsida)
- †Protorosaurus ( Protorosauria)
- †Sauropterygia ( Sauropterygia)
Subclass Lepidosaurs or scaly lizards ( Lepidosauria)
- †Eosuchia ( Eosuchia)
- Beakheads or proboscis ( Rhynchocephalia)
- Scaly ( Squamata): lizards and snakes
Subclass Archosaurs ( Archosauria)
- †Thecodonts ( Thecodontia) - became extinct, giving rise to other representatives of this subclass and, possibly, birds
- Crocodiles ( Crocodylia or Crocodilia)
- †Pterosaurs or flying lizards ( Pterosauria): pterodactyls, etc.
- †Saurischian dinosaurs ( Saurichia) - extinct, perhaps gave rise to birds
- †Ornithischian dinosaurs ( Ornithischia)
Subclass Animalia, or synapsids, or theromorphs ( Synapsida or Theromorpha) - became extinct, but gave rise to mammals.
- † Pelycosaurus ( Pelycosauria)
- †Therapsids ( Therapsida)