Progressive features of the structure of the musculoskeletal system of birds. Birds. excretory system of birds

A bird can fly not only because it has wings. Adapted to flight and the internal structure of the bird's body, and the processes of its vital activity. What features of the internal structure help birds to conquer the airspace?

The musculoskeletal system of a bird, like that of all vertebrates, is formed by a skeleton and muscles attached to it.

Skeleton birds (Fig. 43.1) consists of six sections: the skull, spine, skeletons of the forelimbs (wings) and hind limbs (legs), as well as the belts of the forelimbs and hind limbs. The skeleton of a bird is light: all its bones are thin, and most of them are hollow (Fig. 43.2). In a pigeon, the bones of the skull are slightly thicker than a paper sheet. Birds do not have jaws (they are replaced by a light horny beak) and teeth.

The spine consists of the cervical, thoracic, lumbar, sacral and caudal sections. Due to the almost immovable connection of the vertebrae in the thoracic, lumbar and sacral regions, the bird cannot bend over, as we do. However, this "flaw" in her is compensated by the mobile connection of the vertebrae in the cervical region. Therefore, the dove, bending its neck, deftly collects grain with its beak, and the owl can turn its head 270 °. The limited mobility of the spine is an important adaptation of the bird for flight: in the air it gives the body a compactness.

What is the structure of the chest of a bird? The ribs extending from the vertebrae of the thoracic region are movably connected to the large sternum (sternum). Each rib consists of two parts located at an angle to each other and interconnected semi-movably. This design allows the chest to expand and contract during inhalation and exhalation. The ribs have processes that give the chest additional strength. It not only reliably protects the lungs and heart: the outgrowth of the sternum (keel) is the site of attachment of the main muscles that ensure the movement of the wings.

The clavicles of the pigeon, growing together with the lower ends, form fork. It softens the jolts during the flapping of the wings. The skeleton of the forelimbs, like in all vertebrates, ends with a brush. Its bones are partially fused, creating support for long flight feathers, which experience the greatest stress in flight. The bones of the foot also grow together, forming a tarsus. It lengthens the legs and softens the shock when landing. Birds walk on fingers. material from the site

The pelvic bones in birds do not fuse. They can diverge widely to the sides, so birds can lay large, hard-shelled eggs.

Bird muscles. The most powerful muscles in birds are pectorals, they lower and raise their wings. At one end, these muscles are attached to the keel, and at the other, to the shoulder. Thanks to the developed leg muscles, birds not only move on the ground or swim - they push off the surface with their feet when taking off. The intercostal muscles raise and lower the chest.

Have you noticed that there are light (white) and dark (red) fibers in the muscles of a bird? White fibers are adapted for intensive but short work, for example, during takeoff, and red fibers for long, measured flight. These almost indefatigable muscles work during long flights.

Lesson number 5.

Topic: The evolution of the musculoskeletal system in animals.

Class: 7 B

Goals:

To study the features of the musculoskeletal system of mammals.

To study the complication of the musculoskeletal system in the course of evolution.

Tasks:

educational:

To study the structure and functions of the musculoskeletal system of mammals.

To study the structure and functions of the musculoskeletal system during evolution.

Find out the features of complication in representatives of the musculoskeletal system of different taxa.

developing:

Formation of the ability to establish cause-and-effect relationships.

Developing the ability to work with a book and spreadsheets.

educational:

To generalize the complex of knowledge about the evolution of the musculoskeletal system.

Lesson type: explanation of new material.

Method: illustrative.

Form: group.

Must know after the lesson:

The structure and functions of the musculoskeletal system, ranging from unicellular to chordates.

Features of the complication of the structure of the musculoskeletal system in representatives of different taxa.

During the classes:

Organizational start:

Teacher: Hello guys, sit down! Please open your notebooks and write down the topic of our lesson: "The evolution of the musculoskeletal system."

Learning new material:

Teacher: During a long evolutionary path, animals mastered new territories, types of food, constantly adapted to environmental conditions. In order to survive, animals had to look for food, better hide or defend themselves from enemies, and move faster. Changing along with the body, the musculoskeletal system had to provide all these evolutionary changes.

What do you think are the most remarkable animals?

Student: The most primitive are rhizopods, which do not have a support system, move slowly, flowing with the help of pseudopods, while constantly changing shape.

Teacher: For the first time, the speed of movement changes in flagellates and ciliates. Guys, you have to remember which animals formed the outer skeleton?

Student: The external skeleton was formed in crustaceans, arachnids and insects. It is represented by a chitinous cuticle, a chitinous shell that is impregnated with lime. Muscles are attached to this cover, which allows these animals to move quite quickly. Currently, arthropods are the most common type of animal.

Teacher: And what are the disadvantages of such a skeleton?

Student: It should be noted that the external skeleton also has its drawbacks: it does not grow with the animal, and during growth it is necessary to molt the animal several times, while the animal becomes completely defenseless and becomes easy prey for enemies.

Teacher: Guys, let's write down in the table the information that we have spoken to you:

Teacher: Guys, along with the outer one, there is an inner skeleton. Please tell me what are the advantages of the internal skeleton?

Student: The internal skeleton is devoid of such shortcomings - it grows with the animal and allows even more specialization of individual muscles and their groups, while achieving record speeds of body movement. All chordates have an internal skeleton.

Teacher: The skeleton of most vertebrates is formed by bones, cartilage, tendons. The bones of the skeleton can be connected either motionless - growing together, or movably - with the help of a joint. Muscles are attached to bones in such a way that the bones are set in motion. The skeleton has the following parts:

Axial skeleton;

limb skeleton;

Skull skeleton.

Fish, amphibians, reptiles, birds and mammals have a well-developed spine, which consists of vertebrae. Each vertebra consists of a body, upper and lower arches. The ends grow together and form a canal in which the spinal cord is located. The notochord persists throughout life in beluga and sturgeon.

Guys, what parts does the backbone of fish consist of?

Student: The spine in fish consists of the trunk and tail sections.

The spine is formed by biconcave vertebrae, between which remains of the notochord are preserved. The vertebrae of the trunk region have an upper arch and an upper process, ribs are attached to them from below. In the caudal region, the vertebrae have superior, inferior arches, and spinous processes.

The skull consists of the brain and facial sections. The facial section is represented by the jaws, the hyoid arch and the gill apparatus.

The skeleton of the fins is represented by bone rays, the girdle of the forelimbs is connected to the skull. In addition to paired fins - pectoral and ventral, there are unpaired fins - dorsal and anal.

Teacher: Guys, let's write down what we just said to you.

Systematic group	Dep. Skeleton	Departments of the skeleton	The bones that make up the skeleton
Superclass: Pisces		brain department	Consists of many bones fused immobile.
		facial department	Represented by jaws, hyoid arch and gill apparatus.
	Spine	trunk department tail section
	Skeleton free. final	Unpaired fins (dorsal, caudal, anal)	Represented by the radius bones. In the nutria of the body there are supporting bones.
	Skeleton free. final	Paired fins (pectoral and ventral)	Represented by bone rays.
	Limb belts	Forelimb belt	The girdle of the forelimbs is connected to the skull. Both pectoral and ventral fins are attached to both belts by means of small bones.
	Limb belts	Rear limb belt

What do you think, what are the main features of the skeleton in amphibians?

Student: In amphibians, in connection with the aquatic-terrestrial lifestyle, the axial skeleton has become more complex and is represented by the cervical region, consisting of one vertebra, the trunk - from seven vertebrae with ribs that end freely. The sacral region consists of one vertebra, the pelvic bones are attached to it. Tailed amphibians have several vertebrae in the tail region. The skull is movably articulated with the cervical vertebrae.

Musculature loses its metameric structure and is represented by many individual muscles.

The skeleton of a frog, like that of all vertebrates, is divided into four sections: the axial skeleton, the skeleton of the skull, the skeleton of the limbs and the skeleton of the limb belts.

The axial skeleton is represented by the spine, which, in addition to trunk and tail departments characteristic of fish appeared cervical and sacral departments.

The skull of a frog is movably articulated with a single cervical vertebra, which ensures the movement of the head in a vertical plane (the head cannot move in a horizontal plane).

The number of vertebrae in the trunk of a frog is seven. The frog does not have ribs, but in tailed amphibians, short upper ribs develop on the vertebrae of the trunk, and legless ones have real ribs.

The sacral region includes one vertebra, bearing long transverse processes, to which the iliac bones of the pelvis are attached.

The tail section of the frog ends with a tail bone - urostyle- a bone, which is several vertebrae merged in the process of embryonic development.

The forelimbs are four-fingered (the first finger is reduced), they consist of three sections: shoulder- brachial bone, forearm- fused radius and ulna and brush, represented by bones wrist, metacarpus and phalanges of fingers.

The hind limbs consist of three sections: hips, shins and feet. The thigh consists of the femur, the lower leg is made of the fused tibia and tibia, the foot is made of bones tarsus, metatarsus and phalanges of fingers.

Shoulder girdle frog encircles the body with a wide semicircle and is fixed in the muscles. It is represented by several paired bones: the shoulder blades, ending in wide suprascapular cartilages, crow bones and clavicles, as well as one unpaired bone - the sternum.

Pelvic girdle consists of three paired bones, fused due to heavy loads: iliac, pubic and ischial. With the help of the ilium, the pelvic girdle is attached to the transverse processes of the sacral vertebrae.

Teacher: Guys, please fill in your plate with the help.

Systematic group	Dep. Skeleton	Departments of the skeleton	The bones that make up the skeleton
Class: Amphibians		brain department Facial department	The number of bones is less, as there are no gill covers.
	Spine	Cervical department (1 line) Trunk department (7 stars) Sacral department (1 line) tail section	Formed by vertebrae of different structures. (False) ribs are attached to the trunk vertebrae.
	Skeleton free. final	Forelimbs
	Skeleton free. final	Hind limbs
	Limb belts	Forelimb belt
	Limb belts	Rear limb belt

And now, let's see what features the musculoskeletal system of reptiles has. I am listening to your answers.

Students: The spine of reptiles has five sections: cervical; chest; lumbar; sacral; tail.

In the cervical region, the vertebrae are movably connected. They provide the mobility of the head - a necessary condition for existence on earth. The thoracic and lumbar vertebrae bear the ribs. In some, the ribs connect to the sternum to form the ribcage, providing protection to the organs and better airflow to the lungs. The sacral region consists of two vertebrae. The tail section is well developed. In snakes, all parts of the spine bear ribs, except for the tail. It should be noted that the ribs end freely, which allows them to swallow large food.

Teacher: With the help of a textbook, please write down the listed features on a plate.

Systematic group	Dep. Skeleton	Departments of the skeleton	The bones that make up the skeleton
Class: Reptiles		No difference	No difference
	Spine	Cervical department (more than 1 star) Thoracic Lumbar region Sacral region (2 stars) tail section	Formed by vertebrae of different structures. Ribs are attached to the trunk vertebrae.
	Skeleton free. final	Forelimbs	Shoulder (humerus), forearm (radius and ulna), hand (wrist, metacarpus and 4th phalanges of fingers).
	Skeleton free. final	Hind limbs (There are no differences from amphibians)	Femur (femur), tibia (tibia and fibula), foot (tarsus, metatarsus and 5 phalanges of fingers)
	Limb belts	Forelimb belt (There are no differences from amphibians)	The shoulder blades to which the bones of the forelimbs are attached.
	Limb belts	Rear limb belt (There are no differences from amphibians)	Consists of 3 pairs of fused bones (ilium, pubis and ischium)

Let's see, what is the complication of the musculoskeletal system in birds?

Students: The spine of birds has five sections, like that of reptiles. In the cervical region, there are from 9 to 25 vertebrae connected movably. The fused thoracic vertebrae and ribs connected to the sternum form the chest. The sternum of many birds has a special protrusion - the keel. Muscles that are actively working during flight are attached to the keel. The final thoracic, lumbar, sacral and first caudal vertebrae have fused, creating a powerful sacrum that serves to support the hind limbs, which increases the strength of the skeleton - fitness for flight. The bones of birds are light, many of them are hollow inside.

Despite some differences, the skeleton performs similar functions:

body support;

protection of internal organs;

movement of the body in space.

But at the same time, the skeleton is light and strong due to the thinness of the bones and their pneumaticity.

brain department the skull is large, articulated with the spine by one condyle, as in reptiles.

V facial region huge eye sockets and elongated jaws, modified into a beak.

The skeleton of the body consists of spine and chest. The spine includes five sections: cervical, thoracic, lumbar, sacral and caudal. Saddle joints are characteristic of the cervical vertebrae, which provides greater mobility of the neck (in owls, the angle of rotation of the head reaches 270 degrees).

The posterior thoracic, lumbar, 2 sacral and anterior caudal fused into a complex sacrum.

The middle tails remained free, the latter merged, forming the coccygeal bone.

The chest is formed by ribs, consisting of two bones connected by a joint at an angle to each other. Due to this structure of the ribs, the sternum can approach and move away in relation to the spine during respiratory movements.

On the upper part of the ribs are flat outgrowths that overlap the back ribs, which increases the strength of the chest.

Most birds have a keel on the sternum, to which the pectoral muscles are attached, which set the wings in motion.

The forelimbs consist of the humerus, the forearm is represented by the ulna and radius, the hand consists of fused bones of the wrist and metacarpus, forming a common bone - buckle, and three fingers: second, third and fourth.

Basin of birds open, ischial and pubic bones do not fuse, this is due to the laying of large eggs.

Due to the fact that the main load during walking falls on the hind limbs, the pelvic bones are massive, firmly fused with the posterior thoracic, lumbar, sacral vertebrae, as well as with part of the caudal vertebrae, forming a complex sacrum.

Teacher: Well done guys, let's fill in the remaining columns of the table using your textbook.

Systematic group	Dep. Skeleton	Departments of the skeleton	The bones that make up the skeleton
Class: Birds		Facial department brain department	Formed by fused bones. There are huge eye sockets and a horny beak without teeth.
	Spine	Cervical (from 9 to 25 vertebrae) Thoracic Lumbar sacral department tail section	Formed by vertebrae of different structures. Ribs are attached to the trunk vertebrae, which fuse with the sternum, and it forms a keel, to which the muscles are attached. In birds, the posterior thoracic, lumbar, 2 sacral and anterior caudal fused into a complex sacrum.
	Skeleton free. final	Forelimbs
	Skeleton free. final	Hind limbs	Femur (thigh bone), lower leg (tibia), a tarsus appears (fused bones of the tarsus and spit) and from 1 to 4 phalanxes of the fingers.
	Limb belts	Forelimb belt	The shoulder blades and clavicles are fused and form a fork.
	Limb belts	Rear limb belt	The pelvic bones are fused and adhered to the lumbosacral spine.

Teacher: Now guys, let's look at the skeleton of mammals and describe it in the same way:

Systematic group	Dep. Skeleton	Departments of the skeleton	The bones that make up the skeleton
Class: Birds		Facial department brain department	There is a movable mandibular bone. Formed by fused bones.
	Spine	Cervical department (7 stars) Thoracic (From 9 to 24 stars) Lumbar (from 2 to 9 stars) Sacral department (3–4 stars) tail section	Formed by vertebrae of different structures. Ribs are attached to the trunk vertebrae, which fuse with the sternum, below there are false ribs. The sacral vertebrae fuse together to form the sacrum.
	Skeleton free. final	Forelimbs (Like reptiles)	The shoulder (humerus), forearm (radius and ulna), the hand is modified. There is a reduction of bones and 1 phalanx remains.
	Skeleton free. final	Hind limbs

Birds are animals that not only move on the ground, but also rose into the air, soar in the sky. Therefore, as a result of evolutionary development, a change in the mass and shape of their body was observed. At the same time, there was an accumulation of fat - an energy reserve, friction decreased during movement, and muscle mass increased. At the same time, their skeleton and muscles changed; musculoskeletal system of birds.
In many ways, it is the same as in mammals. The musculoskeletal system of birds consists of the skull, humerus and forearm, shoulder blade, pelvic and femur bones, etc.
At the same time, it is completely different from the musculoskeletal system of mammals. For example, the head of birds is small, because. all the bones of the cerebral skull fused, and their number decreased. The skull is greatly lightened due to the fact that the bones are mostly hollow, and there is a toothless beak, which is covered only by a horny cover. Birds do not have spinal curves like humans do. The "human" chest is expanded, while in animals and birds it is laterally compressed.
The cervical region of the bird skeleton is represented by 11-25 free vertebrae, but the vertebrae of the thoracic region are firmly fastened together and at the same time with the department. The sacral region fused with the girdle of the hind limbs, and the sacrum was formed.
There is a difference in the facial skeleton, and in the girdle of the limbs, and in the limbs themselves. For example, only birds have a keel - a cartilaginous outgrowth that was formed during the fusion of the clavicle with the sternum. In flying birds, the sternum is quite strongly developed, and the keel is large.
The musculoskeletal system of birds includes the hind limbs, which are two large, powerful fused with a complex sacrum. And since the bird walks on two legs, the sacrum itself is also powerful. The sacrum is formed by fused sacral, lumbar, and caudal vertebrae; therefore, it is believed that birds do not have a lumbar region.
The skeleton of a bird differs from the skeletons of other living beings in that it is strong and light. This is achieved, firstly, because the bones of birds are tubular. Secondly, lightness is explained by the cavity of the bones. Therefore, the mass of the skeleton of a bird is somewhere between 5 -15% of its body mass. With the exception of the cervical region, the entire spine is immobile.
Since the forelimbs, as a result of evolutionary development, turned into wings, the hand is almost not developed. But in birds that fly well, large birds make up about 15-20% of the mass, and their special arrangement contributes to the stability of birds in the air.

Standing lower in development than birds and mammals is the class of reptiles. The body of such a reptile consists of a head, necks, torso and limbs, except for snakes, which are devoid of limbs. In structure, the musculoskeletal system of reptiles is close to amphibians, but unlike them, it has a more ossified skeleton. The more progressive structure of the bone skeleton and muscles of such animals determined their mobility. The skeleton of reptiles, like the musculoskeletal system of birds, also consists of their cervical, thoracic, sacral and tail sections. The long ribs join with the sternum to form the ribcage.
Reptiles, unlike other animals, have more dissected muscles, in particular, intercostal muscles. They can regulate the volume of the chest, compress and expand it, thereby performing the process of breathing. Since the ribs of reptiles end freely, this allows them to swallow rather large food. They have a well developed tail.
Summing up, it can be noted that the skeletons of all animals have distinctive features, but perform similar functions. They serve as a support for the body, protect internal organs and help all living things move in space.

Task 1. Perform laboratory work.

Topic: "The external structure of a bird. The structure of feathers".

Objective: to study the features of the external structure of birds in connection with flight.

2. Using the instructions given in paragraph 44 of the textbook, do the laboratory work, draw the structure of the feathers and make an explanation for the drawings.

3. Make a conclusion about the features of the external structure of birds.

The feathers of birds develop from those primordia of the epithelium as the scales of reptiles. Birds are well adapted to flight: the forelimbs are turned into wings, the body has a streamlined shape and is covered with feathers. The main role in flight is played by flapping movements and tail feathers.

Task 2. Fill in the table.

Task 3. Write down the numbers of the correct statements.

Statements:

1. All birds are capable of flight.

2. Birds are the largest class of terrestrial vertebrates in terms of the number of species.

3. Birds usually have four toes on their feet.

4. The flying surface of the wing is formed by contour feathers.

5. There is no fluff in the feather cover of the dove.

6.Down feathers and down are one and the same.

7. The contour pen consists of a rod and a fan.

8. The skin of birds is thin and dry (there is only a coccygeal gland).

Correct statements: 4, 7, 8.

Task 4. Complete the laboratory work.

Topic: "The structure of the skeleton of a bird".

Objective: to study the structural features of the skeleton of birds; note the features associated with flight.

1. Make sure that the workplace has everything you need to complete the lab.

2. Using the instructions given in paragraph 45 of the textbook, complete the laboratory work.

3. Color the bones of the bird's skeleton (green - bones of the spine, blue - bones of the girdle of the forelimbs, brown - forelimbs, red - girdle of the hind limbs, yellow - hind limbs) and label them.

4. Note how the structure of the bird's skeleton is adapted to flight.

The musculoskeletal system well reflects the adaptations of birds to flight. The skeleton is light and durable. Lightness is provided by the pneumaticity of the bones, strength - by their fusion. in the hand, the bones have grown together into a buckle, in the foot - into a tarsus.

Task 5. Write down the numbers of the correct statements.

Statements:

1. The keel (sternum outgrowth) of birds contributes to the dissection of air in flight.

2. The tarsus in birds was formed as a result of the fusion of several bones of the foot.

3. The wing skeleton of a bird is similar to the wing skeleton of an ancient flying lizard.

4. The beak of a bird is a modified upper and lower jaw, devoid of teeth.

5. The wings of a bird rise and fall due to the action of the pectoral muscles.

6. The belt of the forelimbs in birds consists of two shoulder blades and two clavicles.

7. One finger is well preserved in the bird's wing hand.

8. The position of the wings provides the birds with stability in flight.

9. The presence of horny scales is a common feature of reptiles and birds.

10. The length of the neck in birds depends on the number of vertebrae.

Correct statements: 1, 3, 4, 5, 8, 9.

Plan-summary of an open lesson in biology in grade 7B.

Photo report on the site: http://bal-sch30.edumsko.ru/about/news

Lazareva Tamara Vasilievna MBOU "School No. 30", Balashikha

Work experience

Biology

Textbook for 7th grade students of educational institutions / Ed. prof. V.M. Konstantinov

Lesson topic

"The musculoskeletal system of birds"

http://bal-sch30.edumsko.ru/about/news

Class characteristic

The quality of class teaching in I and II academic quarters is 93%. Basically, all students are able to communicate, can draw their own conclusions, analyze, think, and reflect. The class is functional. Almost everyone has the skills of independent work and group activities.

Technological map of the lesson:

Subject, class	Biology, 7 "B" class
Lesson Objectives	For the teacher	For the student
Lesson Objectives	Creation of conditions for the assimilation by children of the structural features and fitness of the musculoskeletal system for flight	Find out the features of the structure of the supporting and motor apparatus of the bird in connection with the ability to fly;
Educational Outcomes	Personal: Formation of a responsible attitude to learning, readiness and ability for self-development and self-education.
	Metasubject: Regulatory UUD: Setting a learning task, Completion of tasks in accordance with the set goal, Answer the questions asked Performing laboratory work Cognitive UUD: Work with text, Work according to a given algorithm, Understanding the information received. Communicative UUD: Ability to listen and engage in dialogue; participate in a group discussion of problems.
	Subject: Mastering the conceptual apparatus of the subject of biology, Formation and consolidation of experience in the use of laboratory observation methods, Find out the structural features of the skeleton and muscles of a bird in connection with its ability to fly.
Educational environment of the lesson	Textbook “Biology. Animals. ”, Grade 7, Konstantinov V.M., Babenko V.G., Kuchmenko V.S. : a textbook for students in grade 7 educational institutions / Ed. prof. V.M. Konstantinov Dove skeletons. Tables. Unified collection of digital educational resources. Interactive tutorial “Animals. Visual Biology.
Technologies and technological methods of organizing educational activities	Problem learning technology
Lesson stages	Teacher actions	Student actions
1. Organizational	Checking students' readiness for the lesson	Get ready for the lesson. Teacher greeting.
2. Checking homework	Distributes the text with the task. Work performance control. Organizes peer review.	Work with text. Analysis and error correction Under the guidance of a teacher, they check the work of a classmate.
3. Updating knowledge	Have you seen a flying dog? What features of the external and internal structure of birds provide the ability to fly?	They give answers to the questions posed, based on previously acquired knowledge and try to suggest the features of the internal structure that allow birds to fly.
4. Setting goals and objectives	Organization of search work of students (goal setting and action plan) What is the backbone of the bird's body? Leading students with leading questions to determine the goal and objectives when studying a new topic. Presentation of the topic and objectives of the lesson.	Answers to questions and, as a result, formulate the goal: elucidation of the structural features of the skeleton and muscles of the bird in connection with the ability to fly
5. Learning new material	Organization of independent work with the textbook. Drawing a parallel with previously studied material (comparison with reptiles). Conducting briefing on the implementation of laboratory work No. 6 "The structure of the skeleton of a bird "I.K. pp. 212-213 Work performance control.	Work with the text of the textbook, answers to the questions posed. Performing laboratory work No. 6 "The structure of the skeleton of a bird "according to the instructional map, pp. 212-213. Filling the table « Features of fitness in the structure of the skeleton of a bird associated with flight
6. Comprehension and consolidation of the studied material	Organization of a collective check of filling in the table « Features of fitness in the structure of the skeleton of a bird associated with flight "using the interactive tutorial" Animals. Visual Biology»	Formulation of conclusions of observations. Expressing your opinion. Frontal and individual work with interactive tests.
7. Reflection	Focusing attention on the final results of educational activities in the lesson.	Identification of the main positions of the new material and how they learned them.
8. Homework	Comments on homework.Learn §45, questions 3, 4. (oral) p. 213	Recording homework in a diary.
9. Summing up	Analysis of the results of the lesson and its compliance with the goals. Announces and comments on student grades.	Formulate the end result of their work.

The theme of the open lesson: "The musculoskeletal system of birds."

The purpose of the lesson: Create conditions for students to learn the structural features and fitness of the musculoskeletal system of birds for flight

I. Knowledge update

"The external structure of birds":

Birds - cold-blooded (warm-blooded)animals whose forelimbs, in connection with the adaptation to flight, turned into wings. The body is covered with feathers and is divided into a head, --(neck), trunk, tail, limbs. The head is small, bears a short beak, consisting of the mandible and mandible. at the basemandibles ( mandibles) nostrils lie. On the sides of the head are large eyes, equipped with movable eyelids and a nictitating membrane. Behind the eyes are ear openings, covered with a tympanic membrane and covered with feathers. The head sits on a longmotionless (mobile)neck. The body of birds is ovoid, compact. The tail is short, tail feathers are attached to it. The forelimbs - wings - are located on the sides of the body. The hind limbs perform a supporting function when moving on the ground.

The skin of birds is thin, dry,not without (deprived)skin glands. Only above the root of the tail is preservedtail (coccygeal)gland. Its fat-like secret is used to lubricate the feathers. It is especially well developed inforest (waterfowl)birds. The secret of the coccygeal gland in the sun turns into vitamin D, which is swallowed by the bird when cleaning the feather. Growths of the stratum corneum of the epithelium form horny covers of the lower and upper jaws, scales on the tarsus and toes, and claws. The feather cover, consisting of contour and down feathers, also belongs to the horny formations of the skin.

The contour pen consists of a core, a core andplanes (fan). The fan is formed by horny plates extending from the rod on both sides - first-order barbs, from which numerous second-order barbs extend with hooks located on them. Hooks of neighboring barbs, interlocking with each other, connect them into a light elastic plate of a fan. The lower part of the trunk, devoid of a fan, is calledby the way. Its base is immersed in leather and secured in a feather bag. Contour feathers are tiled superimposed on each other, covering the entire body. The long and strong contour feathers that form the plane of the wing are called flight feathers, located on the tail -guides (helmsmen).

Beneath the contour feathers lieloose (downy) feathers. They have a very thin stem, and the barbs do not have hooks, so they do not form a fan. Down are down feathers with a very short shaft and heavily pubescent beards that extend in a tuft from the quill. Down feathers and down provideventilation (thermal insulation), because contain a lot of air between the barbs.

Additional questions:

1. What features of the external structure of birds confirm their ability to fly?

2. Why do birds take great care of their feathers?

3. Why don't waterfowl get supercooled on the water in cold weather?

II. Work on the topic:

The task of the lesson is to find out the structural features of the musculoskeletal system of birds in connection with their fitness for flight.

Why don't dogs fly?

What features of the external and internal structure of birds provide the ability to fly?

A. Bird skeleton. Working with the tutorial:: page 211

a) the meaning of the skeleton (support, body shape, movement, protection, etc.)

b) what changes in the structure of the skeleton of birds in comparison with reptiles occurred in connection with the fitness for flight? (The skeleton is strong and light. The bones have air cavities. Many bones have fused.)

B. Laboratory work No. 7 Instructional map p.212-213

Topic. The structure of the skeleton of a bird.

Target. To study the structural features of the skeleton of birds. Note the traits associated with flight.

Equipment: bird skeleton, tweezers.

Progress

Consider the skeleton of a bird. Determine the shape of the skull. Consider the bony base of the beak and the large eye sockets, the junction of the mandible to the skull, and the skull to the spine.

Examine the sections of the spine. Name them.

In the cervical region, pay attention to the structure of the first two vertebrae, and the saddle shape and movable connection of other vertebrae. Note the significance of this feature in the life of a bird.

Locate the thoracic spine, pay attention to the fixed connection of the vertebrae. Consider the structure of the sternum and ribs.

Name the bones of the girdle and free forelimbs. Pay attention to the bones of the shoulder, forearm, buckle, fingers.

Locate the hindquarters. Consider it, paying attention to the strength of the connection of the pelvic bones with the spine. Explain the significance of this structural feature of the skeleton in the life of a bird.

Examine the bones of the hind limbs. Name them. Pay attention to the tarsus - the long bone of the foot. Count the number of fingers.

Note in the structure of the bird's skeleton the traits of fitness associated with flight. Fill the table

Structural features, connection with flight

The skull is bony, characterized by lightness and a voluminous braincase. In front, it ends with a beak, and from the sides it carries large eye sockets. Teeth and secondary palate are absent.

Spine

The thoracic vertebrae (from 3 to 10), fusing motionlessly, form a complex breast bone. All lumbar, sacral and part of the caudal vertebrae fuse and form a complex sacrum, with which the pelvic bones are fixedly fused. The coccygeal vertebrae form the tail section. The last few caudal vertebrae fuse into the coccygeal bone. Steering feathers are attached to it.

Rib cage

Each rib of birds consists of two parts - dorsal and ventral, which are respectively articulated with the thoracic spine and sternum. Both parts of the ribs are also movably connected to each other. All birds (except ostriches) have a high keel on the sternum. The muscles that move the wing are attached to it.

Limb belts

The shoulder girdle is formed by three paired bones, the scapula, the coracoid and the clavicle. The clavicles fuse from below and form a fork.

The pelvic girdle provides strong support for the hind limbs due to the fixed fusion of the complex sacrum with the ilium. Due to the fact that the pelvic bones in the abdominal region are widely spaced and do not grow together, birds can lay large eggs. On the sides of the pelvis are the articular cavities for the heads of the femur.

limbs

The forelimbs are modified into wings and consist of the humerus, bones of the forearm (ulna and radius). The bones of the wrist and metacarpus fuse into an unpaired metacarpal-carpal bone. Of the fingers, only three are preserved, corresponding to the 2nd, 3rd, and 4th fingers of the five-fingered hand. The reduction in the number of fingers and the formation of the metacarpal bone provide strength to this section of the wing during flight.

The hind limb consists of the thigh, lower leg, tarsus and foot. The tibia and fibula are fused. In connection with the fusion of the bones of the metatarsus and tarsus, a tarsus was formed. Most birds have four toes on their feet: three pointing forward and one backward.

B. Student's message (leading task):

D. Musculature of birds:

a) What muscles lower the wings?

b) What are they attached to?

c) What muscles raise the wings?

d) How many muscles provide movement of the hind limbs?

The muscular system, due to the variety and complexity of movements, is more differentiated than that of reptiles. The most powerful muscles are located on the body and the movements of the limbs are carried out. The largest - the pectoral muscle, serves to lower the wings. On the one hand, it is attached to the sternum, coracoid and carina, and on the other to the humerus. The subclavian muscle is located under the pectoral and raises the wing. It starts from the coracoid and sternum and attaches to the head of the shoulder. About 30 muscles are involved in the movement of the hind limb. They are especially strongly developed in running birds. Well developed neck muscles. The intercostal muscles are attached to the ribs.

III . Consolidation of knowledge:

Completion of task No. 11 (orally) and 18 in a notebook from the interactive tutorial “Animals. Visual Biology»

IV . Homework:

learn §45, questions 3, 4. page 213

V . Material used:

Textbook for 7th grade students "Biology" of educational institutions / Ed. prof. V.M. Konstantinov

Photo report on the open lesson on the website: http://bal-sch30.edumsko.ru/about/news