What are reptiles? How and where does the reptile embryo develop? Do reptiles lay eggs or not?

703-01. Are the judgments about the characteristics of reptiles correct?
1. The body of reptiles is covered with thin, bare skin that secretes mucus.
2. In snakes and some lizards, the eyelids are fused and become transparent.
A) only 1 is correct
B) only 2 is correct
C) both statements are correct
D) both judgments are incorrect

Answer

703-02. Reptiles, unlike amphibians, are true land animals, since they
A) have two pairs of lever limbs
B) have a developed nervous system
C) adapted to terrestrial reproduction and development
D) in addition to skin respiration, they carry out pulmonary respiration

Answer

703-03. Fish and reptiles have a similar structure
A) skeleton
B) circulatory system
B) digestive system
D) respiratory system

Answer

703-04. What feature ensures the ability of reptiles to reproduce on land?
A) protection of offspring
B) cold-bloodedness
B) the structure of the egg
D) the number of eggs laid

Answer

703-05. The transition of animals to reproduction on land became possible with the advent of
A) asexual method of reproduction
B) external fertilization
B) sexual reproduction
D) internal fertilization

Answer

703-06. What respiratory organs are characteristic of the depicted animal?

A) gills
B) lungs
B) air sacs
D) trachea

Answer

703-07. Ancient reptiles were able to finally switch to a land-air lifestyle because they
A) concern for offspring appeared
B) the cells of the body were supplied with mixed blood
B) there was an internal bone skeleton
D) internal fertilization appeared

Answer

703-08. Which reptile organ system is shown in the picture?

A) circulatory
B) respiratory
B) digestive
D) nervous

Answer

703-09. Are the following statements about reptiles true?
1. Female reptiles lay fertilized eggs with a high yolk content.
2. The development of reptiles occurs with transformation.
A) only 1 is correct
B) only 2 is correct
C) both statements are correct
D) both judgments are incorrect

Answer

703-10. The peculiarity of the structure of the skin of reptiles is
A) complete absence skin glands
B) the presence of bone scales
B) the presence of mucous glands
D) the presence of sweat and sebaceous glands

Answer

703-11. Viviparity in some species of lizards arose as an adaptation to life in
A) hot climate
B) tree hollows
B) northern latitudes
D) aquatic environment

Answer

703-12. Which of the characteristics that emerged in the ancestors of reptiles allowed reptiles to completely transition to a land-based way of life?
A) five-fingered limb
B) three-chambered heart
B) the shell of an egg
D) bone skeleton

Answer

703-13. What is characteristic of the animal shown in the picture?

A) gill breathing
B) reproduction in water
B) two-chambered heart
D) unstable body temperature

Answer

703-14. If the air temperature drops, terrestrial reptiles
A) begin to eat heavily
B) migrate to more favorable areas of the earth
C) do not change their behavior
D) temporarily hibernate

Answer

703-15. Are the judgments about the reproduction of reptiles correct?
1. Fertilization in reptiles is external.
2. The larvae of snakes and lizards do not look like adult animals.
A) only 1 is correct
B) only 2 is correct
C) both statements are correct
D) both judgments are incorrect

Answer

703-16. Indicate what adaptations for reproduction on land arose in reptiles during the process of evolution.
A) external fertilization and a small reserve nutrients in an egg
B) internal fertilization, a large supply of nutrients and dense shells in the egg
B) external fertilization, absence of a dense shell in the egg
D) a small supply of nutrients in the egg, internal fertilization

Answer

703-17. Are the judgments about the life processes of reptiles correct?
1. Reptiles breathe through the skin and lungs.
2. The organs of reptiles receive blood richer in oxygen than that of amphibians.
A) only 1 is correct
B) only 2 is correct
C) both statements are correct
D) both judgments are incorrect

Representatives of reptiles (more than 4 thousand species) are true terrestrial vertebrates. Due to the appearance of the embryonic membranes, they are not associated with water in their development. As a result of the progressive development of the lungs, adult forms can live on land in any conditions. Reptiles living in the species are secondary aquatic, i.e. their ancestors switched from a terrestrial lifestyle to an aquatic one.

Remember! Reptiles and reptiles are the same class!

Reptiles, or creeping things, appeared at the end Carboniferous period, approximately 200 million years BC. when the climate became dry, and in some places even hot. This created favorable conditions for the development of reptiles, which turned out to be more adapted to living on land than amphibians. A number of traits contributed to the advantage of reptiles in competition with amphibians and their biological progress. These include:

• The membranes around the embryo and a strong shell (shell) around the egg, protecting it from drying out and damage, which made it possible to reproduce and develop on land;
• development of five-fingered limbs;
• improvement of the structure of the circulatory system;
• progressive development of the respiratory system;
• appearance of the cerebral cortex.

The development of horny scales on the surface of the body, protecting against adverse influences, was also important. environment, first of all, from the drying effect of air. The prerequisite for the appearance of this device was liberation from skin respiration due to the progressive development of the lungs.

A typical representative of reptiles is the sand lizard. Its length is 15-20cm. It has a well-defined protective coloration: greenish-brown or brown, depending on its habitat. During the day, lizards are easy to see in a sun-warmed area. At night they crawl under stones, into holes and other shelters. They spend the winter in the same shelters. Their food is insects.

On the territory of the CIS, the most widespread are: in the forest zone - the viviparous lizard, in the steppe - the sand lizard. The spindle is a lizard. It reaches 30-40 cm, has no legs, which reminds it of a snake, this often costs it its life. The skin of reptiles is always dry, devoid of glands, and covered with horny scales, scutes or plates.

The structure of reptiles

Skeleton. The spinal column is already divided into cervical, thoracic, lumbar, sacral and caudal sections. The skull is bony, the head is very mobile. The limbs end in five fingers with claws.

The muscles of reptiles are much better developed than those of amphibians.

Digestive system . The mouth leads into the oral cavity, equipped with a tongue and teeth, but the teeth are still primitive, of the same type, and serve only to capture and hold prey. The alimentary canal consists of the esophagus, stomach, and intestines. At the border of the large and small intestines the rudiment of the cecum is located. The intestines end in a cloaca. Digestive glands are developed: pancreas and liver.

Respiratory organs. The respiratory tract is much more differentiated than in amphibians. There is a long trachea that branches into two bronchi. The bronchi enter the lungs, which look like cellular, thin-walled sacs, with a large number internal partitions. The increase in the respiratory surfaces of the lungs in reptiles is associated with the lack of cutaneous respiration.

Excretory system represented by the kidneys and ureters flowing into the cloaca. The bladder also opens into it.

Circulatory system . Reptiles have two circles of blood circulation, but they are not completely separated from each other, due to which the blood is partially mixed. The heart has three chambers, but the ventricle is divided by an incomplete septum.

Crocodiles already have a real four-chambered heart. The right half of the ventricle is venous, and the left part is arterial - the right aortic arch originates from it. Converging under the spinal column, they unite into the unpaired dorsal aorta.

Nervous system and sensory organs

The brain of reptiles differs from the brain of amphibians in the greater development of the hemispheres and cerebral vault, as well as the separation of the parietal lobes. Appears for the first time, the cerebral cortex. 12 pairs of cranial nerves arise from the brain. The cerebellum is somewhat more developed than in amphibians, which is associated with more complex coordination of movements.

At the front end of the lizard's head there is a pair of nostrils. The sense of smell in reptiles is better developed than in amphibians.

The eyes have eyelids, upper and lower, in addition, there is a third eyelid - a translucent nictitating membrane that constantly moisturizes the surface of the eye. Behind the eyes is a rounded eardrum. Hearing is well developed. The organ of touch is the tip of the forked tongue, which the lizard constantly sticks out of its mouth.

Reproduction and regeneration

Unlike fish and amphibians, which have external fertilization (in water), reptiles, like all non-amphibious animals, have internal fertilization, in the body of the female. The eggs are surrounded by embryonic membranes that enable development on land.

The female lizard quickly lays 5-15 eggs in a secluded place at the beginning of summer. The eggs contain nutritional material for the developing embryo and are surrounded on the outside by a leathery shell. A young lizard emerges from the egg, looking like an adult. Some reptiles, including some species of lizards, are ovoviviparous (i.e., a baby immediately emerges from a laid egg).

Many species of lizards, when grabbed by the tail, break it off with sharp lateral movements. Throwing back the tail is a reflex response to pain. This should be considered as an adaptation thanks to which lizards escape from enemies. A new one grows in place of the lost tail.

Diversity of modern reptiles

Modern reptiles are divided into four orders:

• Protolizards;
• Scaly;
• Crocodiles;
• Turtles.

Protolizards represented by a single type - hatteria, which is one of the most primitive reptiles. The tuateria lives on the islands of New Zealand.

Lizards and snakes

Scaly animals include lizards, chameleons and snakes. This is the only relatively numerous group of reptiles - about 4 thousand species.

Lizards are characterized by well-developed five-fingered limbs, movable eyelids and the presence of an eardrum. This order includes agamas, poisonous lizards, monitor lizards, true lizards, etc. Most species of lizards are found in the tropics.

Snakes are adapted to crawling on their belly. Their neck is not pronounced, so the body is divided into head, torso and tail. The spinal column, which contains up to 400 vertebrae, is highly flexible thanks to additional articulations. The belts, limbs and sternum are atrophied. Only some snakes have preserved a rudimentary pelvis.

Many snakes have two poisonous teeth on their upper jaws. The tooth has a longitudinal groove or duct through which the poison flows into the wound when bitten. The tympanic cavity and membrane are atrophied. The eyes are hidden under transparent skin, without eyelids. The snake's skin becomes keratinized on the surface and is periodically shed, i.e. moulting occurs.

Snakes have the ability to open their mouths very wide and swallow their prey whole. This is achieved by the fact that a number of skull bones are connected movably, and the lower jaws in front are connected by a very tensile ligament.

The most common snakes in the CIS are snakes, copperheads, snakes. The steppe viper is listed in the Red Book. For its habitat, it avoids agricultural lands, but lives on virgin lands, which are becoming less and less, which threatens it with extinction. Feeds steppe viper(like other snakes) are predominantly mouse-like rodents, which is certainly useful. Its bite is poisonous, but not fatal. She can attack a person only by accident, being disturbed by him.

The bites of poisonous snakes - cobra, epha, viper, rattlesnake and others - can be fatal to humans. Of the fauna, the gray cobra and sand faff, which are found in Central Asia, as well as the viper, found in Central Asia and Transcaucasia, the Armenian viper, living in Transcaucasia. Bites common viper and copperhead are very painful, but usually not fatal to humans.

The science that studies reptiles is called herpetology.

IN lately snake venom is used in medicinal purposes. Snake venom is used for various bleedings as a hemostatic agent. It turned out that some drugs obtained from snake venom reduce pain in rheumatism and diseases of the nervous system. To receive snake venom In order to study the biology of snakes, they are kept in special nurseries.

Crocodiles are the most highly organized reptiles, having a four-chambered heart. However, the structure of the partitions in it is such that venous and arterial blood are partially mixed.

Crocodiles are adapted to water image life, and therefore have swimming membranes between the fingers, valves that close the ears and nostrils, and a velum that closes the pharynx. Crocodiles live in fresh waters, come to land to sleep and lay eggs.

Turtles are covered above and below with a dense shell with horny scutes. Their chest is motionless, so their limbs take part in the act of breathing - when they are drawn in, the air leaves the lungs, when they stick out, it enters them. Several species of turtles live in Russia. Some species are eaten, including the Turkestan tortoise, which lives in Central Asia.

Ancient reptiles

It has been established that in the distant past (hundreds of millions of years ago) they were extremely common on Earth. various types reptiles. They inhabited land, water, and less often air. Most species of reptiles became extinct due to climate change (cold temperatures) and the rise of birds and mammals, with which they could not compete. Extinct reptiles include orders of dinosaurs, wild-toothed lizards, ichthyosaurs, flying lizards, etc.

Dinosaur Squad

This is the most diverse and numerous group of reptiles that has ever lived on Earth. Among them were both small animals (the size of a cat and smaller) and giants, whose length reached almost 30 m and weight - 40-50 tons.

Large animals had small heads long neck and a powerful tail. Some dinosaurs were herbivores, others were carnivores. The skin either had no scales or was covered with a bone shell. Many dinosaurs ran galloping on their hind limbs, leaning on their tail, while others moved on all four legs.

Squad Animal-toothed

Among the ancient land reptiles there were representatives of a progressive group, which resembled animals in the structure of their teeth. Their teeth were differentiated into incisors, canines and molars. The evolution of these animals went in the direction of strengthening their limbs and belts. In the process of evolution, mammals arose from them.

Origin of reptiles

Fossil reptiles have great value, since they once dominated the globe and from them came not only modern reptiles, but also birds and mammals.

Living conditions at the end of the Paleozoic changed dramatically. Instead of warm and humid climate cold winters appeared and dry and hot climate. These conditions were unfavorable for the existence of amphibians. However, under such conditions, reptiles began to develop, whose skin was protected from evaporation, a terrestrial method of reproduction, a relatively highly developed brain and other progressive characteristics appeared, which are given in the characteristics of the class.

Based on a study of the structure of amphibians and reptiles, scientists came to the conclusion that there are great similarities between them. This was especially true for ancient reptiles and stegocephalians.

• In very ancient lower reptiles, the vertebral column had the same structure as in stegocephals, and the limbs - like in reptiles;
• the cervical region of reptiles was as short as that of amphibians;
• the chest bone was missing, i.e. they did not yet have a real chest.

All this suggests that reptiles evolved from amphibians.

They explored new, drier habitats. Reptiles gained an advantage in the struggle for existence due to the emergence of adaptations to prevent the loss of water by the body and the transition to a terrestrial method of reproduction.

Having conquered the land, the ancient reptiles reached an unprecedented peak. In the Mesozoic they were represented by a huge variety of forms.

The class Reptiles, or Reptiles, is represented primarily by terrestrial animals. They reproduce and develop exclusively on land. Even those species that live in water breathe atmospheric air and go ashore to lay eggs.

The body of reptiles consists of a head, torso and tail. It is protected from drying out by the skin. Breathing is exclusively pulmonary. The more complex structure of the circulatory system allowed reptiles to more successfully adapt to the conditions ground-air environment habitat compared to amphibians. Reptiles are cold-blooded animals, their activity depends on the ambient temperature, so most species live in areas with a hot climate.

Many species of reptiles have elongated bodies, for example snakes, lizards, and crocodiles. In turtles it is round and convex. Reptiles have dry skin without glands. She's covered horny scales, or shields, and almost does not participate in gas exchange. As reptiles grow, they periodically shed their skin. Reptiles have two pairs of legs on the sides of their body. The exceptions are snakes and legless lizards. The eyes of reptiles are protected by eyelids and a nictitating membrane (third eyelid).

Respiratory system

Due to the loss of skin respiration, the lungs of reptiles are well developed and have a cellular structure. The rib cage is formed for the first time in the skeleton. It consists of the thoracic spine, ribs and sternum (absent in snakes). The volume of the chest can change, so reptiles breathe by sucking air into the lungs, and not swallowing it, like amphibians.

Nervous system

The brain of reptiles is large and larger complex structure than in amphibians: the size of the cerebellum and cerebral hemispheres. This is associated with their better coordination, mobility, and development of the senses, especially vision and smell.

Nutrition and excretion

Most reptiles are predators, only land and sea turtles feed primarily on plants. The organs of excretion are the kidneys. The need to use water sparingly leads to the fact that the waste products of reptiles contain almost no water.

Circulatory system

The heart of reptiles is three-chambered: it consists of a ventricle and two atria. Unlike amphibians, an incomplete septum appears in the ventricle of reptiles, dividing it in half. There are two circles of blood circulation.

In reptiles, internal fertilization is not associated with water. This gave them an advantage in the struggle for existence over amphibians, and they spread widely over land. Reptiles reproduce by laying eggs. After fertilization, the embryo is covered with egg and embryonic membranes. They provide protection and participate in the processes of nutrition and excretion.

Predatory reptiles regulate the number of their victims. Lizards and snakes, feeding on insects and rodents, benefit humans. Snake venom is used in medicine. Beautiful and valuable products are made from crocodile and snake skin.

If you meet a viper in the forest, remember that it never attacks a person first and will try to hide. You should not step on it, try to catch it or kill it. The victim of a bite should be given tea and taken to a doctor as soon as possible. Incisions, application of a tourniquet, and drinking alcohol can only harm him.

Task 1. Write what explains the more complex structure respiratory system reptiles compared to amphibians.

The emergence of air respiratory organs in chordates occurred more than once and was often only idioadaptations and did not lead to noticeable biological progress. An example is lungfish, as an adaptation to life in often drying up reservoirs; amphibians have adapted to breathing dry air, i.e. developed a way to avoid drying out of the lungs (bronchi). This is all idio-adaptation.

Task 2. Write down the numbers of the correct statements.

Statements:

1. The shell of a reptile egg protects the embryo from drying out.

2. The respiratory surface of the lizard's lungs is larger than that of the newt.

3. All reptiles have a three-chambered heart.

4. The body temperature of reptiles depends on the ambient temperature.

5. All reptiles lay eggs on land.

6. In reptiles living in northern regions Live births are more common.

7. Mixed blood flows in the ventricle of a lizard’s heart.

8. There is no diencephalon in the brain of reptiles.

9. Viviparous lizards do not produce eggs.

10. U sea ​​turtles salts are excreted from the body through special glands.

Correct statements: 1, 2, 4, 6, 9, 10.

Task 3. Color the internal organs of the lizard (red - circulatory organs, green - organs of the digestive system, blue - respiratory organs, brown - excretory organs, black - reproductive organs) and label them.

1. Excretory organs: 1) kidney; 2) bladder; 3) cloaca.

2. Reproductive organs: 1) testes; 2) vas deferens.

3. Digestive system: 1) mouth; 2) nostrils; 3) oral cavity; 4) pharynx; 5) esophagus; 6) trachea; 7) lung; 8) liver; 9) stomach; 10) pancreas; 11) small intestine; 12) large intestine; 13) cloaca.

4. Circulatory system: 1) heart; 2) carotid artery; 3) aorta; 4) pulmonary artery; 5) vein; 6) intestinal vein; 7) pulmonary vein; 8) capillary network.

Task 4. Fill out the table.

Comparative characteristics
Comparable characteristic	Class
	Amphibians	Reptiles
Coverings of the body	smooth thin skin rich in skin glands	keratinized dry skin forms scales
Skeleton	torso, skull, limbs, spine (4 sections)	skull, torso, limbs, spine (5 sections)
Organs of locomotion	limbs	limbs
Respiratory system	skin and lungs	lungs
Nervous system	brain and spinal cord	brain and spinal cord
Sense organs	eyes, ears, tongue, skin, lateral line	eyes, ears, nose, tongue, sensory cells of touch. hair.

Task 5. The structure of the reproductive organs of amphibians and reptiles is not significantly different. However, amphibians typically lay thousands of eggs, many times more than reptiles. Give reasons for this fact.

Reptiles have internal fertilization. Reptiles lay eggs, from which developed young hatch. The eggs of reptiles are better protected, which means they have a better chance of surviving in this world. And in amphibian organisms, fertilization occurs in water (i.e. external fertilization). Amphibians lay eggs, from which larvae hatch, which then become young. Eggs, that is, eggs, of amphibians do not have a hard protective shell, so there are predators that eat amphibian eggs. That's why amphibians lay a lot of eggs, because most of the eggs (larvae) will die.

Reptiles- typical terrestrial animals and their main method of movement is crawling, reptiles on the ground. Key Features The structures and biology of reptiles helped their ancestors leave the water and spread widely across the land. These features primarily include internal fertilization And egg laying, rich in nutrients and covered with a dense protective shell, which facilitates their development on land.

The body of reptiles has protective formations in the form scales, dressing them with a continuous cover. The skin is always dry, evaporation through it is impossible, so they can live in dry places. Reptiles breathe exclusively with the help of their lungs, which, compared to the lungs of amphibians, have a more complex structure. Intensive lung breathing became possible thanks to the appearance of a new skeletal section in reptiles - chest. The chest is formed by a number of ribs connected on the dorsal side to the spine, and on the abdominal side to the sternum. The ribs, thanks to special muscles, are mobile and contribute to the expansion of the chest and lungs during inhalation and their collapse at the moment of exhalation.

Changes in the structure of the respiratory system are closely related to changes in blood circulation. Most reptiles have a three-chambered heart and two circuits of blood circulation (as do amphibians). However, the structure of the reptile heart is more complex. In its ventricle there is a septum, which at the moment of contraction of the heart almost completely divides it into the right (venous) and left (arterial) halves.

This structure of the heart and the location of the main vessels, different from that of amphibians, more strongly delineates the venous and arterial flows, therefore, the body of reptiles is supplied with blood that is more saturated with oxygen. The main vessels of the systemic and pulmonary circulation are typical of all terrestrial vertebrates. The main difference between the pulmonary circulation of amphibians and reptiles is that in reptiles the cutaneous arteries and veins have disappeared and the pulmonary circulation includes only pulmonary vessels.

About 8,000 are known today existing species reptiles that live on all continents except Antarctica. Modern reptiles are divided into orders: protolizards, scaly, crocodiles And turtles.

Reproduction of reptiles

Fertilization in terrestrial reptiles internal: the male injects sperm into the female’s cloaca; they penetrate the egg cells, where fertilization occurs. The female's body develops eggs, which she lays on land (buries in a hole). The outside of the egg is covered with a dense shell. The egg contains a supply of nutrients, due to which the development of the embryo occurs. The eggs do not produce larvae, as in fish and amphibians, but individuals capable of independent life.

First Lizard Squad

TO proto-lizards refers to "living fossil" - tuateria- the only species that has survived to this day only on small islands near New Zealand. This is a sedentary animal, leading mainly night look life and appearance lizard-like. Hatteria in its structure has features that are similar to reptiles and amphibians: the vertebral bodies are biconcave, with a chord preserved between them.

Otrad scaly

Typical representative scaly - quick lizard. Its appearance indicates that it is a terrestrial animal: the five-fingered limbs do not have swimming membranes, the fingers are armed with claws; the legs are short, and therefore the body, when moving, seems to crawl along the ground, every now and then coming into contact with it - reptiles (hence the name).

Lizards

Although the lizard's legs are short, it can run quickly, quickly escaping from its pursuers into its burrow or climbing a tree. This was the reason for its name - quick. The lizard's head is connected to the cylindrical body using the neck. The neck is poorly developed, but will still give the lizard's head some mobility. Unlike a frog, a lizard can turn its head without turning its whole body. Like all land animals, it has through nostrils, and its eyes have eyelids.

Behind each eye, in a small depression, is the eardrum, connected to the middle and inner ear. From time to time, the lizard sticks out of its mouth a long, thin tongue forked at the end - an organ of touch and taste.

The lizard's body, covered with scales, rests on two pairs of legs. The humerus and femur bones are parallel to the surface of the earth, causing the body to sag and drag along the ground. The ribs are attached to the thoracic vertebrae, forming the rib cage, which protects the heart and lungs from damage.

Digestive, excretory and nervous system lizards are generally similar to the corresponding amphibian systems.

Respiratory organs - lungs. Their walls have a cellular structure, which significantly increases their surface area. The lizard does not have skin respiration.

The lizard's brain is better developed than that of amphibians. Although it has the same five sections, the forebrain hemispheres are larger in size, and the cerebellum and medulla oblongata are much more massive.

The sand lizard is distributed very widely from the Black Sea to the Arkhangelsk region, from Baltic Sea to Transbaikalia. In the north, it gives way to a viviparous lizard similar to it, but more adapted to the cold climate. In the southern regions there are many different types lizards Lizards live in burrows, which are summer weather leave in the morning and evening, but no further than a distance of 10-20 m from the mink.

They feed on insects, slugs, and in the south - locusts, caterpillars of butterflies and beetles. Within a day, one lizard can destroy up to 70 insects and plant pests. Therefore, lizards deserve protection as very useful animals.

The lizard's body temperature is not constant (the animal is active only in the warm season); it drops sharply even if a cloud approaches the sun. With a longer drop in temperature, the lizard loses mobility and stops eating. During the winter it hibernates; can tolerate freezing and cooling of the body down to -5°, -7°C, while all the life processes of the animal slow down significantly. Gradual warming returns the lizard to active life.

In addition to the sand lizard and viviparous lizard, there are many other species of lizards. Common in Ukraine and the Caucasus large green lizard : in desert areas - agama lizards with a long flexible and unbreakable tail.

Predatory lizard gray monitor lizard , living in the deserts of Central Asia. Its length is up to 60 cm. The monitor lizard eats arthropods, rodents, eggs of turtles and birds. The largest specimens of monitor lizards discovered by herpetologists (the science that studies reptiles) on the island of Komolo reach 36 cm. legless lizard - spindle.

Chameleons

Chameleons in appearance they resemble medium-sized lizards, with a helmet-shaped outgrowth on the head and a laterally compressed body. It is a highly specialized animal, adapted to woody image life. His fingers are fused together like pincers, with which he tightly grasps the branches of trees. The long and prehensile tail is also used for climbing. The chameleon has a very unique eye structure. The movements of the left and right eyes are not coordinated and independent of each other, which provides some advantages when catching insects. Interesting feature chameleon is its ability to change skin color - protective device. Chameleons are common in India, Madagascar, Africa, Asia Minor and southern Spain.

Snakes

In addition to lizards, the order Squamate includes snakes. Unlike chameleons, snakes are adapted to crawling on their stomachs and swimming. Due to wave-like movements, the legs gradually completely lost their role as organs of locomotion; only some snakes retained their rudiments (a boa constrictor). Snakes move by bending their legless body. Adaptation to crawling was manifested in the structure internal organs snakes, some of them completely disappeared. Snakes have no bladder and only one lung.

Snakes see poorly. Their eyelids are fused, transparent and cover their eyes like a watch glass.

Among the snakes there are non-venomous and poisonous species. The largest non-venomous snake is boa- lives in the tropics. There are boas up to 10 m long. They attack birds and mammals, strangling their prey by squeezing it with their body, and then swallowing it whole. Large boas living in tropical forests, are also dangerous for humans.

From non-venomous snakes widespread snakes. The common snake is easily distinguished from poisonous snakes by two orange crescent spots on the head and round pupils of the eyes. It lives near rivers, lakes, ponds, feeding on frogs, and sometimes small fish, swallowing them alive.

Poisonous snakes include viper, cobra, or spectacled snake , rattlesnake etc.

Viper easily recognized by the long zigzag dark stripe running along the back. In the upper jaw of the viper there are two poisonous teeth with tubules inside. Through these tubules, the poisonous liquid secreted by the victim enters the wound. salivary glands snakes, and the prey, such as a mouse or small bird, dies.

By destroying huge numbers of mice and locusts, vipers benefit humans. However, their bites can cause long-term illness and even death in animals and even humans. The venom of such snakes as asian cobra, American rattlesnake.

Wounds formed when a person is bitten by a snake look like two red dots. Painful swelling quickly occurs around them, gradually spreading throughout the body. A person develops drowsiness, cold sweats, nausea, delirium, and in severe cases, death occurs.

If a person is bitten by a poisonous snake, it is necessary to immediately take first aid measures., remove excess poison near the wound with blotting paper, cotton wool or a clean cloth, if possible, disinfect the bite site with a manganese solution, strictly protect the wound from contamination, give the victim strong tea or coffee, and ensure rest. Then take him to the hospital as quickly as possible for immediate administration of anti-snake serum. Where they are found poisonous snakes, you can't walk barefoot. Care must be taken when picking berries, protecting your hands from snake bites.

Otrad crocodiles

Crocodiles- these are the largest and most highly organized predatory reptiles, adapted to an aquatic lifestyle, living in tropical countries. Nile crocodile Spends most of its life in water, where it swims beautifully, using a strong, laterally compressed tail, as well as hind limbs that have swimming membranes. The crocodile's eyes and nostrils are elevated, so it only needs to raise its head out of the water a little and it can already see what is happening above the water, and also breathe atmospheric air.

On land, crocodiles are slow to maneuver and, when in danger, rush into the water. They quickly drag their prey into the water. These are various animals that the crocodile lies in wait at watering places. It can also attack humans. Crocodiles hunt mainly at night. During the day they often lie motionless in groups on the shallows.

Turtle squad

Turtles differ from other reptiles in their well-developed, durable shell. It is formed from bone plates, covered on the outside with horny substance, and consists of two shields: the upper convex and the lower flat. These shields are connected to each other from the sides, and there are large gaps in front and behind the joints. The head and forelimbs are exposed from the front, and the hind limbs from the back. Almost everything aquatic turtles- predators, land animals - herbivores.

Turtles usually lay hard-shelled eggs on land. Turtles grow slowly, but are among the long-livers (up to 150 years). There are giant turtles (soup turtle up to 1 m long. Weight - 450 kg. marsh turtle- up to 2 m and up to 400 kg). They are objects of fishing.

Meat, fat, eggs are used for food, and a variety of horn products are made from the shell. We have one species of turtles - marsh turtle, lives up to 30 years. During the winter it hibernates.