Lizard - a ground-based cold-blooded animals whose body is adapted to onshore lifestyle.It lives in the forests, steppes, deserts, mountains.A small slender body covered with numerous outside lizards horny scales, exclusively pulmonary respiration.It moves with the help of the legs, tail and body touching the ground (groveling).Why lizard skin can not breathe?The answer to this question will help the study of the structural features and lifestyle of one of the typical representatives of the class of reptiles.
lizard nimble
in a sunny spot among grass and branches, on the warm stones you can find a small graceful animal.This nimble and common lizard.The length of her slender body reaches 15-20 cm (with a tail).Painting - a greenish-brown with black spots of various sizes.The outer layer of dry solid skin - thickened, horny scales in the form of the whole body and the flaps on the head.On the fingertips have claws, they lizard clings to the bark of trees, rocks for climbing.Scaled cover protects the body from drying out and damage.The air does not penetrate through it, that's why the lizard skin can not breathe, enjoys only light.They supply the body with oxygen, which is necessary for the body's cells for energy.During warmer months, several times a lizard sheds.Scales inhibits the growth of the animal, so the horny layer peels off and there is a new patches.
structure lizard lizard
torso twists, and often in contact with the ground.This movement gave way to the name of the class of animals - reptiles, or reptiles.This group includes the detachment of scaly, lizard suborder.Numerous representatives have common features that allow them to combine into a single group.Consider the external structure of the lizard:
- body consists of the head, trunk, long tail, four legs;
- pointy head in front of the department goes into a short thick neck;
- eyes protected by the upper and lower eyelids, they are constantly wet because of translucent nictitating membrane - the third century;
- on his head, a pair of nostrils, through which the air passes;
- external opening of the hearing organ, covered the eardrum, located behind the eyes;
- organ of touch - long tongue, forked at the end;
- limbs consist of three divisions, on his feet - five fingers, no webbing between them.
Features lizards
Reptiles - difficult arranged land animals, some of which are adapted to aquatic life.There are external features that distinguish lizards on amphibians:
- neck between the head and torso;
- no swimming webbing on the fingers short legs - claws;
- dry skin with a horn cover;
- third eyelid.
At night lizard hiding in burrows, under rocks or stumps, in the autumn in temperate latitudes, like frogs hibernate.Amphibians gas exchange in this period continues through the thin veil of the body.Why lizard skin can not breathe, like a frog?Reptiles lost during evolution capacity for gas exchange through the skin.However, the body's metabolism of reptiles is slower than that of the birds.During warmer months, mobile lizard, hunts for prey in the cold weather becomes sluggish, less feed.
Breath lizards
in the thoracic region of the body attached to the spine lizard ribs protecting the heart and lungs from damage.The air through the nasal openings enters the mouth passes into the larynx and trachea, and then - in the bronchi.Light like a lizard frog breathing bags, but have a more complex structure.When expanding the thorax air is sucked in, and narrowing - there is an exhalation.These movements involved intercostal and abdominal muscles.The light fills the air cells separated by partitions, densely permeated by capillaries.Why lizard skin can not breathe, like a frog?Amphibians naked wet skin - an additional breathing organ, especially needed during hibernation.After integument oxygen from the air enters the bloodstream, and carbon dioxide passes into the environment.Reptilian body cover horny scales, which have blood vessels.Therefore, skin breathing lizard missing.
ability to regenerate
lizard's body is bent when it crawls using claws clinging to the slightest unevenness of the ground or the bark.The animal can climb the trunk of a tree, on a rocky slope.In addition to the speed of movement, there is a protective coating, in harmony with the natural habitat.Some species have the ability to change skin tones, and other menacing hiss, scaring off predators.The thick muscular tail helps when traveling and protects against attacks.There is an interesting property that have a lizard.When the stalker attacks them from behind and holds the tail, it will easily break off and take some time to squirm.The attacker fascinated by this movement, and the lizard escapes in a hole or thickets of grass.Instead of the lost animal regenerates (restore) new tail, shorter and thicker than the former.
suborder lizards
representatives of this taxonomic group can be found in all climatic zones except tundra and polar deserts.In the world there are more than 5900 species, united in the family.By Agamova are species of lizards, leading arboreal or terrestrial life.Some are capable of gliding flight (genus Draco).The largest family of lizards - Komodo (3 m).
representatives of the family of chameleons change color of his body.Males have a basilisk terrifying ridges and spines along its back.These lizards swim well and can run on water, holding on its surface due to the impact webbed feet.The name of the genus derives from the resemblance to the mythical basilisk monster.Iguanas - major representatives of the suborder of lizards.Thus, the length of the common iguana - 1.9-2 m. Paws small geckos and Agam covered a variety of tiny protrusions that help adhesion to different surfaces, even glass.In legless lizards completely missing limbs, but they differ from snakes movable eyelids eyes and the presence of the shoulder girdle in the skeleton.
Representatives of all the families of lizards demonstrate an ideal adaptation to specific habitats.Imperfect thermoregulation they compensate for the fact that hide in shelters from hypothermia and overheating.Falling into a deep sleep, lizards escape the winter cold in the hot desert - Go to the night life.
