Birds are animals that are not only moved along the ground, but also rose into the air, soaring in the sky. Therefore, as a result of evolutionary development, there was a change in the mass and form of their body. In this case, the accumulation of fat - the energy stock was decreased when the friction was moved, muscle mass was increased. At the same time, their skeleton and muscles changed, i.e. Musculoskeletal system birds.
In many ways, it is the same as in mammals. The musculoskeletal system of birds consists of a skull, shoulder bone and forearm, blades, pelvic and femoral bones, etc.
At the same time, it is completely different than the musculoskeletal system of mammals. For example, the head in birds is small, because All bones of the brain skull have grown, and their amount decreased. The skull is greatly facilitated due to the fact that the bones are mostly hollow, and there is a toothless beak, which is covered only with a horny cover. In the birds there are no spinal fibes like a person. The breast "human" cell is expanded, and in animals and birds it is compressed from the sides.
The cervical skeleton of birds is represented by 11-25 free vertebrae, but the vertebrae of the chest department is fastened with each other and at the same time from the department. The sacral department has agrees with the belt of the hind limbs, and formed the crushes.
There is difference in the facial skeleton, and in the belt of the limbs, and in the limbs themselves. For example, only in birds there is a keel - cartilage growing, which was formed during the captivity of the clavicle with the sternum. In the flying birds, the yard is developed quite strongly, and Kiel is large.
The musculoskeletal system of birds includes the hind limbs, which are two large, powerful struck with a complex sacrum. And since the bird goes on two legs, then the crushes itself is also powerful. The crushes is formed by controversial sacral, lumbar, tail vertebrae, therefore they believe that there are no lumbar separation.
The skeleton of birds differs from the skeletons of other living beings by the fact that it is durable and light. This is achieved, firstly, because the bones in the birds are tubular. Secondly, the ease is explained by the bone cavity. Therefore, the mass of the skeleton of the bird is somewhere 5 -15% of the mass of its body. With the exception of the cervical department, the entire spine is stationary.
Since the forefronts as a result of evolutionary development turned into wings, then the brush is almost not developed. But in birds that fly well, large amounts are somewhere 15-20% of the mass, and their special location contributes to the resistance of birds in the air.

Standing below the level of development than birds and mammals is the class of reptiles. The body of such a reptile consists of a head, neck, torso and limbs, besides snakes and that are devastated. According to the structure, the rebuilding system of reptiles is close to amphibian, but unlike them, has a more infinite skeleton. The more progressive structure of the bone skeleton and musculature of such animals determined their mobility. The skeleton of reptiles, as well as the musculoskeletal system of birds, also consists of their cervical, thoracic, sacrilate and tail departments. Long ribs are connected to the sternum, and the chest is formed.
Reptiles, in contrast to other animals, have more dismembered muscles, in particular, interrochemical muscles. They can adjust the amount of the chest, compress and expand it, thereby performing the process of breathing. Since Röbra reptiles ends freely, it allows them to pull out quite large food. They have an irony of the tail of the tail.
Summing up, it can be noted that the skeletons of all animals have distinctive features, but perform similar functions. They serve as a body support, protect the internal organs and help move to everything in space.

Author: Kostyuchenko A.N., teacher of biology of NMO "Lyceum №84", Novokuznetsk
Individual survey: work on cards 1 - 5 ...
Frontal survey:
- Where are the birds inhabit?
- What do birds differ in the external structure from the reptiles?
- What signs of similarities can be noted in their structure?
All birds are capable of flight. In the number of types among other classes of ground vertebrate animals. The birds on the legs are usually 4 fingers: three of them are directed forward, and one backwards. Birds are modified upper and lower jaws, The devoid of teeth. The dental surface of the wing is formed by the contour feathers. The Pigeon Powder does not have a fluff. The first feathers and the fluff is the same. The accompanied feather consists of a rod and appeal. The birds are covered with crumbling and down feathers. Machine feathers in most birds are attached to elbow bone and brush bones.
Objective: To study the features of the skeleton of birds associated with the flight. Material and equipment: Dove skeleton - four instances, table "Bird class", textbook drawings. Tutorial card. (See Card)
Why do birds refer to the type of chord, vertebral subtype? What is the meaning of an animal skeleton? List the main parts of the vertebrate skeleton.
Skeletons of vertebrate animals have a lot of general features
Skeleton birds (pigeon) is very light due to the presence of air paths in the bones
The skeleton is very durable - the captivity of a number of bones among themselves
8-18% of the mass of the whole body!
cervical
breast
lumbar
sacral
tail
Skull is formed by subtle spongy bones, the boundaries between which are visible only in young birds
Only the cervical department is well moving, the rest perform the support function. The number of cervical vertebrae varies from 11 (parrots) to 25 (swans)
The chest consists of thorough breast vertebrae (3-10). They depart from the ribs that join the sternum.
The last thoracic vertebra, 5 lumbar, 2 sacrats and 5 tails form a single bone-complex crescent.
The skeleton of the front limbs (wing) consists of three departments: brush, forearm, shoulder. The brush has three underdeveloped fingers.
The belt of the front extremities: Powerful bones (shrocides), which have grown the clavicle that form a fork, ensure the movement of the wings.
The bones of the foot are merged into one bone - a set, which is an additional lever that increases the length of the step. Falangi fingers are movably attached to the set.
Lack of teeth; the presence of sternum with a kelle, to which the muscles are attached; ribs consisting of two parts (mobility when breathing in flight); reduction of the number of fingers, the fusion of small bones - the strength of this department; the durable connection of the vertebrae of the breast and lumbar sacrive seats is reliable Supporting torso while flying.
The muscles of the hind extremities and the neck are developed. Great thoracic muscles (20% of body weight), their function is the lowering of the wings, start from the keel and end on the shoulder. On the feet of birds there are muscles with long tendons. When landing, the tendons are stretched and compressed fingers.
1. Exclude extra: a) the blades; C) Voronene bones; b) clavicle; D) Shoulder bone.2. Between the first and second concept there is a correspondence. Find a similar match between the third and one of the five concepts of concepts: LCD - forelexing bone -? A) Tsevka; B) stop; C) shin; D) thigh; E) brush.
3. summarize the following concept with one: lonely bone, shoulder bone, brush bones - ... 4. The same in meaning is the concepts of "Atlant" and: a) the cervical department; C) the second cervical vertebra; b) the first neck vertebra; D) crescents.5. The science of birds is: a) poultry farming; C) cynology; b) ornithology; D) zoology.
Explore the textbook text, with. 210-212. Notebook on printed-based task 135. Message !!!
http://webzsl.narod.ru/content/sites/bio/site02/muscles.htm http://www.paranormal-news.ru/news/2009-3-27-1637 http://images.yandex. EN http://tana.ucoz.ru/index/0-8 http://www.floranimal.ru/

Preview:

Bird class

Topic: "Features of the musculoskeletal system of birds due to adaptability

to fly

Objectives: Acquaint students with the peculiarities of the musculoskeletal system of birds in connection with the adaptability to flight.

Formation of skills: analyze, compare, summarize, work with a tutorial, tables.

Equipment: Skeleton of bone fish, frogs, birds, dove table. Distribution material card-photocopy pattern "Bird skeleton structure" without designations.

During the classes:

I. Organizational moment (1-2 minutes).

Hello guys sit down (slide 1).

II. Check knowledge (5-10 minutes).

1. Individual survey: work on cards 1-5.

2. Front Poll (Slide 2).

1. Where do birds live?

1. What do birds differ in the external structure from the reptiles?
2. What signs of similarities can be noted in their structure?

3. Test.

Write down the rooms of the right judgments (slide 3).

1. All birds are capable of flying.
2. Birds - the largest class in the number of species among other classes of ground vertebrates.
3. In the birds on the legs usually 4 fingers: three of them are directed forward, and one back.
4. The beak of birds is a modified upper and lower jaw, devoid of teeth.
5. The flying surface of the wing is formed by contour feathers.
6. The pigeon does not have a fluff.
7. Down feathers and fluff is the same thing.
8. The contour pen consists of a rod and appealed.
9. Bird's body is covered with crumbling and down feathers.

10. Fly feathers in most birds are attached to the elbow bone and
brush bones.

Answer: 2, 3, 4, 5, 6, 9, 10.

III. Studying a new material (25-30 minutes).

Let us turn to the study of our topic - to meet the peculiarities of the musculoskeletal system of birds and try to remember how these fixtures are associated with flight. To do this, carry out the laboratory work "The structure of the skeleton of the bird" (slide 4).

Laboratory work

"Bird skeleton structure"

Goal: examine the features of the structure of the skeleton of birds associated with the flight.

Material and equipment:the skeleton of dove is four copies, table "Bird class", textbook drawings.

Recommendations for training for the lesson: In the absence of a dispensing material "Bird skeleton" of the factory production for work, you can use cards - photocopies of the drawings "The structure of a skeleton of birds" without designations.

Tutorial card.

1. Consider the skeleton of birds. Find the skull, spine chest, the skeletons of the limbs. What features can be noted in their structure? What is the pneumaticity of the bones?

Bird skeleton structure

1. Why do birds refer to the type of chord, vertebral subtype?
2. What is the meaning of an animal skeleton?
3. List the main parts of the vertebrate skeleton.

The skeleton of birds in general is similar to the skeleton of other vertebrate animals known to you, but it also has a number of distinctive features (slide 5). Pay attention to the skeleton dove. It is very light due to the presence of air paths in the bones. The total weight of the skeleton is 8-18% of the mass of the whole body, at the same time the skeleton of birds is strong due to the captivity of a number of bones among themselves (slide 6).

In the axial skeleton - the spinal column is distinguished by five departments: cervical chest, lumbar, sacral, tail (slide 7).

Pay attention to the skull of birds. It is formed by subtle spongy bones, the boundaries between which are visible only in young birds. Compared with reptiles in the bird skull, much more brain box, and large, the jaws are devoid of teeth and form a beak (slide 8).

The number of cervical vertebrae varies depending on the type of birds from 11 (dove) to 23-25 \u200b\u200b(swan). The first vertebra is Atlant, most birds have the shape of the bone rings, the second - the epistroinet is mounted with a dental process that provides a movable connection of the head with a torso. The remaining cervical vertebrae saddle, which necessitates the significant mobility of the vertebrae relative to each other. Features of the cervical vertebrae allow birds to freely turn the head 180 °, and some (owls, parrots) - and by 270 °. This makes it possible to produce complex and rapid movements head when grabbing moving production, cleaning the plumage, building nests, etc. (Slide 9)

Breast vertebrae in birds 3-10. Floating among themselves, they form the dorsal bone and very durable joints are connected to a complex sacrum, thanks to this, the torso area of \u200b\u200bthe axial skeleton is still immovable, which is important when flying.

Ribs are born to breast vertebra. Each edge consists of two departments - spinal and abdominal, movably connecting with each other and forming an angle directional to the top. The ribs of moving joints are tested with vertebrae and sternum, which, along with a developed intercostal muscles, provides a change in the volume of body cavity (which is important for breathing). The strength of the chest increases with hooked outgrowths, reinforced on the spinal departments and expanding to the subsequent edge. Big and has a keel, to which muscles are attached, lowering wings.

All lumbar, sacrats (two) and part of the tail vertebrae are motionless of each other in the monolithic bone - a complex cross. In total, it includes 10-22 vertebra, the boundaries between which are not visible. The bones of the pelvic belt (sedlication, pubic and iliac) are fixed with it. This ensures the stillness of the torso department, which is very important when walking (slide 10).

Free tail vertebrae (they are 5-9) are fought in the cockerel - Pigty to which the steering feathers are attached to the fan.

In birds, compared with amphibian and reptiles, significant changes were subjected to a skeleton of the front and rear limbs. The skeleton of the front limb is reinforced due to the instance of the bones of the brush and reduce the number of fingers to three (slide 11). The front limb belt is also adapted to the flight: powerful robes (shrocides), the collaborators that form the fork, ensure the movement of the wings (slide 12).

The structure of the skeleton of the rear limb allows birds a born in walking. The bones of the foot are merged into one bone - a set, which is an additional lever that increases the length of the step. The phalange of the fingers (slide 13) are movably attached to the set.

1. So, what adaptations to the flight are in the skeleton of the bird? (Slide 14)

1. lack of teeth;
2. the presence of sternum with a kelle, to which muscles are attached;
3. ribs consisting of two parts - such an articulation ensures their mobility when bird breathing in flight;
4. reducing the number of fingers, the merging of small bones of the brush ensures the strength of this wing part carrying the largest load in flight;
5. the durable connection between the vertebrae of the infant and lumbar sackeling of the skeleton serves as a reliable support of the body during the flight.

Well developed in birds and muscles. The most developed (up to 25% of the masses of the bird) muscles moving with wings. They are shifted to the chest, and this, with one side, facilitates a moving organ (wings), and on the other, it makes a fixed center of gravity of the body, which is very important for a straight-line flight. The most developed in birds are big breast muscles, lowering wings, which make up 50% of the mass of all muscles. Raise the wings of the plug-in muscles, which are also well developed and are located under large chest. The birds of the hind limbs and neck (slide 15) are strongly developed.

IV. Fastening the material studied (3-5 minutes).

1. Exclude superfluous (slide 16):

a) the blades; c) Voronene bones;

b) clavicle; d) shoulder bone.

2. Between the proposed first and second concept there is a certain compliance. Find a similar compliance between the third and one of the five concepts of concepts:

Local bone - forearm Big bone -?

a) Tsevka; b) stop; c) shin; d) thigh; e) brush.

3. summarize the following concepts one (slide 17):

lock bone, shoulder bone, dice brush - ...

4. The same in meaning is the concepts of "Atlant" and:

a) cervical department; c) the second cervical vertebra;

b) the first cervical vertebra; d) the crushes.

5. The science of birds is:

a) poultry farming; c) cynology;

b) ornithology; d) zoology.

Answers: 1 - g; 2 - a; 3 - front limb; 4 - b; 5 B.

Homework. Explore the text of the textbook, p. 210-212. Proceduce a report on laboratory work (Table). Notebook on printed-based task 135. Message (Archeopterix). (Slide 18)

Thank you for attention! (Slide 19, 20)

Card number 1.

1. What feathers are the flying surface of the bird wing?

2. To what bones of the skeleton are they attached?

Card number 2.

1. For what signs of the external structure, the bird can be recognized among other vertebrates?

2. What are the birds among themselves?

Card number 3.

1. What types of feathers are you known?

2. What do they differ among themselves?

3. What are their functions?

Card number 4.

1. The bird body is not completely covered with feathers. Naked or almost bare parts of the body are on the stomach, body sides and neck. How can I explain the presence of the birds of the skin deprived of the feathers?

2. What is the role of feathery in the life of the bird?

Examine the skeleton of the head - skull. Pay attention to the eye and beak. In connection with what caused these features in the structure of the skull? Why is the beak devoid of teeth?

Pay attention to the bone of the body. Why only the cervical spine has a moving connected vertebra? Consider the bones of the chest: breast and breast ribs. Find a high non-spare crest of breasts - keel. What value does it have? What are the features of the structure of the ribs of birds distinguish them from reptiles? Why did these features arise?

Consider the forefinder belt and wing skeleton. List the main front limb departments. What is the similarity of the front limb of bird and reptile? Why did differences arise?

Consider the belt and skeleton of the back limb. How are bones among themselves? Why? What departments are distinguished in the skeleton of the bird's rear limb?

Summing up the work: fill in the table.

Bird skeleton structure

Musculoskeletal system. Skeleton and muscles of birds.

Topic: Skeleton birds.

Goal: Examine the skeleton of birds.

Tasks:

1. Educational: Familiarize students with the features of the skeleton of birds in connection with the adaptability to flight; Give the concept of "Tsevka", "Kiel".

2. Developing: Development of concepts: "Spine", "Taz", "Cresks", "Ground"; skills work with a textbook; Development of thinking.

3.Toist: The formation of scientific worldview, environmental education (on the example of identifying adaptations to the factors of the environment in the structure of the skeleton).

• The skull represents a single bone, only the lower jaw is movably connected to it.

Pelvic bones are growing with the spine. Delivering, sacral and part of the tailing vertebrae form a complex cross.

1 - lumbar vertebrae, 2 - sacral vertebrae, 3 - tail vertebrae,

4 - iliac bone, 5 - Sedal Bone, 6 - Lobcovaya Bone

Light bones: All long bones are tubular, have air cavities, there are small air cavities in some flat bones.

• The skeleton of the trowel body on the side:
• 1 - the last cervical vertebrae, 2 - thoroughly vertebrae (spinal bone),
• 3 - cervical ribs, 4 - breast ribs, 5 - hook-shaped processes, 6 - sternum body,
• 7 - Kiel, Breasts, 8 - Complex, 9 - movable tail vertebrae,
• 10 - Pigtyl, 11 - Koracaid, 12 - Village, 13 - Shovel,
• 14 - articular wpadin for the shoulder head, 15 - iliac bone,
• 16 - Sedal Bone, 17 - Lobcovaya Bone,
• 18 - Gearing Wpadina for High Head

Spinal departments

1. The following (9-25 transcriptions), 2. Herpic (3-10 vertebrae), 3. Family (6 vertebrae), 4.Crestz (2 transcription), 5. Equate (5 Grounded with a complex sacrum, 6 remained free, 4 last Grounded in the tailbone).

• The chest, or thoracic bone (6) - a wide and long, concave from the inside of the bone plate, carrier in the midline high bone ridge - spider spray (7). A sharp increase in the surface of the sternum due to its growth and the formation of keel - direct device to flight; It provides the possibility of attaching powerful muscles leading to the movement of the wing. At the front end of the sternum on the sides of the keel, large articulated areas are located, providing a durable attachment to the body of the sternum of Korakoids (11). On the side edges of the sternum are small recesses, which serve for articulation with the lower ends of the abdominal departments of the ribs.

Front limb belt

The belt of the front limbs consists of pair of sword-shaped blades, two wicked claviers and two large cacopids resting in the sternum.

• 1. Description. 2.Lock. 3, Voronary Bone. 4.Grudin. 5.Kil.

Skeleton Front Free Limit - Wing

• Skeleton Wing Crows: 1 - shoulder bone, 2 - radiation bone, 3 - elbow bone, 4 - independent wrist bones, 5 - buckle (sprinkled wrist bones and peasants), 6 - Falangi II finger, 7 - the only phalanx I finger, 8 is the only phalanx III of the finger

Changes in connection with the adaptation to the flight.

• The skeleton of the front limb, which turned into the wing, was subjected to significant changes. Shoulder ( 1 ) - Powerful tubular bone, which is included in the articular shock joint. The character of the joint surfaces is noticeably limited to the possibility of rotational movements in the shoulder joint, which ensures the stability of the wing in flight. Powerful epiphesis of the distal end of the shoulder form the articular surfaces for articulation with two bones of the forearm: more direct and thin radiation (, 2 ) and more powerful, slightly curved elbow bone ( 3 ). On the surface of the elbow bone, the tubercles are visible - the places of attaching the churches of secondary flying feathers. The nature of the joint surfaces of the elbow joint provides a strong connection of the bones of the shoulder and the forearm and limits the rotational movements and in this joint. At the same time, a large mobility remains in the same plane - the wing plane, which allows the bird to fold the wing alone and change its area when changing the flight mode. Sharp changes due to adaptation to the flight occurred in the brush structure. In the proximal session of the wrist, only two independent bones are preserved ( 4 ). They almost motionless connected with bones of the forearm. The movable joint is located between them and the rest of the wrist bones, so it is called intercardal. The remaining bones of the wrist and all the bones of the income merge into a single formation - a buckle ( 5 ). The skeleton of fingers is dramatically reduced. Two phalanges of the II of the finger are preserved ( 6 ), continuing the axis of buckles. From the finger, one phalanx is preserved (Fig. 7 ), a beam of feathers forming a ward is attached to it (, 4 ). III finger is also represented by one phalange ( 8 ) attached to the base of the first phalanx II of the finger. These conversions in the skeleton of the brushes provide a solid support for primary flying feathers - parts of the wing carrier in flight the greatest load.

Skeleton free rear limb.

• Powerful long bones of the skeleton of the hind limbs, the appearance of an additional lever, a sharp relief of the articular surfaces - all this ensures the strength and mobility of the hind limbs.

The skeleton of the rear limb of a croron : 1 - femoral bone, 2 - Bedroom Cheschka, 3 - Goleza-replous), 4 - Small Berbsovaya Bone, 5 - Tsevka (Rights Robes are reputed and plus), 6 - interbranch joint, 7 - phalanges of fingers; I - IV - fingers

• Well developed neck muscles. More than 30 muscles provide the movements of the hind limbs. They begin on the bones of the pelvis, hips, shin. Long tendons are suitable for fingers, which when landing the birds are stretched on the branch, squeezing the fingers, so the birds do not fall from the branches during sleep. Intercostal and some other muscles provide the mobility of the chest. There are special muscles moving feathers.

Muscle contraction scheme

Scheme of muscle contraction when picked up (a) and lowering (b) wings: 1 - big breast muscles; 2 - Connect Muscles

• Important for the flight of birds are large breast muscles lowering wing. They are attached to a quille of breasts and end in tendons on the bones of the wing.

Ostrich - Labor Birds.

Ostrich - Labor Birds. They are characterized by a complete absence of a keel and a weak thigh muscles; The skeleton is not pneumatic, with the exception of femoral bones. Wings in ostrichs are underdeveloped; Two fingers end with claws, or spurs. The hind limbs are long and strong, with all two fingers. One of the fingers ends with the likeness of the horny hoof (the resulting claw) - the bird relies on it when running. Ostrich when running is able to develop speed up to 60-70 km / h.

Penguin or penguins - Family of fluttering seabirds, the only one in the detachment pingguin-shaped (Sphenisciformes.). In the family of about 20 modern species (according to various sources - from 18 to 20). All representatives of this family swim well and dive.

• The forefoulder fines of the penguins are modified into elastic flippers, which, thanks to a special skeleton device, are in a half-hearted state and during swimming under water rotate almost purifying in the shoulder joint. The wings of these birds are practically not bended, as they are flippers covered with scaly short feathers. They help penguins only to row during swimming and diving. Some types of penguins are able to perform up to 120 flywheel movements per minute. The connecting paws and tail serve the penguins a kind of steering wheel. A powerful breasting muscles, controlling the movement of wings-flops, are attached to a well-developed quille. In some types of penguins, breast muscles make up a quarter of the entire body mass, which is much more than many flying birds. The bones forming the skeleton of the wings are thoroughly glorified. Bone density penguins are very different from other birds and are similar to marine mammals.

Exercises on the material passed.

• What changes in the structure of the skeleton of birds compared with the reptiles occurred in connection with the adaptability of the flight?
• What are the features of the location and structure of the muscles of birds? Explain the reasons.
• Why is the flying birds high kil?
• What are the features of the structure of the pelvis of birds? What is the associated such structure?

Homework: § 45, Fill out a table

Skeleton departments

Bones forming department

Features

• Vague. Teacher Biology-N.F.neverova. MBOU SS №10 City Dimitrovgrad Ulyanovsk region.

The bird can fly not only because she has wings. Adapted to the flight and inner structure of the body of the bird, and its vitality processes. What features of the internal structure help birds conquer the airspace?

The musculoskeletal system of the bird, as in all vertebrates, is obsessed with a skeleton and muscles attached to it.

Skeleton birds (Fig. 43.1) consists of six departments: skull, spine, the skeletons of the front limbs (wings) and the hind limbs (legs), as well as belts of the front and rear limbs. The skeleton of the bird is light: all its bones are thin, and most of them are hollow (Fig. 43.2). At the bone of the skull's bone slightly thicker paper sheet. In the birds there are no jaws (they replaced the light horny beak) and teeth.

The spine consists of a cervical, thoracic, lumbar, sacred and tail departments. Because of the almost fixed connection of calls in breast, lumbar, and sacral divisions, the bird can not be touched as we do. However, this "disadvantage" of her com-pensated by moving vertebrae in the cervical unit. Therefore, the pigeon, bending the neck, deftly collects the beak grain, and the owl can turn the head to 270 °. Limited mobility of a post-night light is an important feature of the bird to the flight: in the air it gives the body compactness.

What is the structure of the poultry chest? Ribs, separating from calls of the thoracic, movably connected to a large breast coach (sternum). Each edge consists of two parts located at an angle to each other and interconnected semi-moving. This design allows the chest expand and narrow during inhalation and exhalation. The ribs have processes that give the chest additional strength. It not only reliably protects the lungs and heart: the ease of sternum (keel) is the place of attaching the main muscles, providing the movement of the wings.

Clavicle pigeons, fucked by lower ends, form fork. She softens the shock at the wailing of the wings. The skeleton of the front of course steits, as in all vertebrates, ends with a brush. Its bones partially grow up, creating a support for long flying feathers experiencing the greatest loads in flight. The bones of the foot are growing, forming a set. It lengthens the legs and softens the push when the landing. Birds walk on the fingers. Material from site.

The bones of the pelvis in the birds do not grow. They can scatter to diverge to the sides, so the birds can postpone large, coated with solid shell eggs.

Muscles of the bird. The most powerful muscles in birds are breasts, they lower and raise wings. One con-tsom these muscles are attached to Kil, and the other to the shoulder. Thanks to the developed muscles of the birds, the birds are not only moved along the ground or float - they are repelled from the surface when taken. Intercostal muscles raise and lower the chest.

Have you noticed that there are bright (white) and dark (red) fibers in the muscles of birds? White fibers are adapted to intense, but short work, for example, when taken, and red - to a long time-dimensional flight. These almost tireless muscles work during long flights.

Bird class - warm-blooded animals whose body is covered with feathers (the only group of animals), and the front co-nonsense turned into wings; Fellows - legs. Birds fly beautifully, surpassing all other vertebrates in this regard. Also, birds are well moved along the ground, climb on trees, many dive and swim in water. Birds are extremely diverse in size, forms, painting, chants and adapted to habitat in various climatic conditions. There are about 9 thousand species.

The exterior structure of the bird

Birds have a head, neck, torso, limb and tail. The head of birds is small, there are beaks, eyes, nostrils. The beak is formed by the bone jaws stretched forward, which are covered with horny covers from above. There are no teeth in birds, which makes it easier to skull. At the base of the top of the beak are nostrils. Rounded eyes are covered with two centuries and a blinking meal. Ear holes are hidden under the neck under feathers. The movable neck connects his head with a compact torso.

Features Body Body

Signs	Body body features
Body shape	Thrust
	Dry skin covered with horny feathers
Types of Peryev	1. Contour - creates a body shape and helps when flying; 2. Down feather and fluff - keep warm
	Easy and durable due to: Estraging bones (bones brushes, pelvis, skull) Air cavities inside the bones of the aircraft muscles are attached to the keel (chest)
	Big chest (lower wings); Connected (raise wings)
Digestive system	Food digestion in 2-3 hours (rapid metabolism for maintaining a pedigree body temperature) Beak -\u003e Through -\u003e Esword (with Goobom) -\u003e Stomach (from two departments - muscular and ferrous) -\u003e Intestinal -\u003e Cloac
Respiratory system	Cellular lungs and additional air bags in body cavities and bones - to improve gas exchange and overheating protection. Double breathing.
Circulatory system	Four-chamber heart (two atrium and two joy-daughter), two circles circulation
Nervous system	The cerebellum is well developed; The hemispheres of the front brain are developed (complex behavior, instincts)
Reproduction	Internal fertilization, the female laying eggs containing the supply of nutrients for the embryo and protected by a limestone shell and a subseposition shell
Development of birds	Spring: formation of pairs -\u003e Changing of males -\u003e Nest -\u003e Singing eggs (from 1-2 to 15-20 pcs.) -\u003e On-sitting eggs -\u003e Caring for offspring. Chicks: 1. Out - appear dressed by Pup, with open eyes and can get out of the nest and follow the mother. 2. Nests - appear helpless, with strokes of eyelids, long do not leave the nests for a long time.