Birds are human feathered friends. Their role in nature is invaluable. Read about them and their protection in the article.
Birds: general characteristics
Birds are highly organized warm-blooded animals. In nature, there are nine thousand species of modern birds. The characteristic features of the class are the following:
- Feathers.
- Rigid corneal beak.
- No teeth.
- A pair of forelimbs are transformed into wings.
- The chest, pelvic girdle and the second pair of limbs have a special structure.
- The heart has four chambers.
- There is an air bag.
- The bird incubates eggs.
Birds, the general characteristics of which are presented above, are able to fly due to the listed features. This distinguishes them from other classes of vertebrate animals.
Appearance on earth
The origin of birds is explained by several theories. According to one of them, birds are supposed to live in trees. First they jumped from branch to branch. Then they glided, then made small flights within the same tree and finally learned to fly in open space.
Another theory suggests that the origin of birds is associated with the ancestors of the birds, which were reptiles with four legs. As the scales evolved, they became feathers, which allowed the reptiles to jump over a short distance. Later, the animals learned to fly.
The origin of birds from reptiles
Based on this theory, we can say that the ancestors of birds were also crawling reptiles. At first, their nests were on the ground. This attracted predators who constantly destroyed nests along with chicks. Taking care of their offspring, the reptiles settled in the thick of tree branches. At the same time, a hard shell began to form on the eggs. Before that, they were covered with a film. Instead of scales, feathers appeared, which served as a source of heat for the eggs. The limbs became longer and covered with plumage.
The origin of birds from ancient reptiles is obvious, according to scientists. The ancestors of birds begin to take care of their offspring: they feed the chicks in the nest. To do this, solid food was crushed into small pieces and put into the beaks of the babies. With the ability to fly, primitive birds of the ancient time period could better defend themselves against the attacks of their enemies.
Ancestors - water birds
The origin of birds, according to another theory, is associated with their waterfowl cousins. This version owes its existence to the remains of ancient birds that were found in China. According to scientists, they were waterfowl and lived more than a hundred million years ago.
The theory is that birds and dinosaurs have lived together for sixty million years. Among the finds were feathers, muscles, membranes. Examining the remains, paleontologists made the following conclusion: the ancestors of ancient birds swam. They dived to get food from the water.
If you study the origin of birds, it is not difficult to find similarities between them and representatives of other classes. The plumage is the most prominent feature of the bird's appearance. Other animals have no feathers. This is the difference between birds and other animals. the following:
- The toes and tarsus of many birds are covered with corneal scales and shields, like those of reptiles. This means that the scales on the legs can replace feathers. It is characteristic that the rudiments of feathers in birds and reptiles do not differ. Only birds then develop feathers, and reptiles develop scales.
- Investigating the origin of birds, the features of which are incredible with reptiles, scientists have determined that the jaw apparatus is more noticeable. Only in birds it turned into a beak, while in reptiles it remained the same, like in turtles.
- Another sign of similarity between birds and reptiles is the skeletal structure. The skull and spine are articulated with only one tubercle located in the occipital region. Whereas in mammals and amphibians, two tubercles are involved in this process.
- The location of the pelvic girdle of birds and dinosaurs is the same. This can be seen from the skeleton of the fossil. This arrangement is associated with the load on the pelvic bones when walking, since only the hind limbs are involved in holding the body.
- Birds and reptiles have a four-chambered heart. In some reptiles, the septum of the chambers is incomplete, and then arterial and venous blood mix. Such reptiles are called cold-blooded. Birds have a higher organization, in comparison with reptiles, they are warm-blooded. This is achieved by removing the vessel that carries blood from the vein to the aorta. In birds, it does not mix with arterial.
- Another similar feature is the incubation of eggs. This is typical for pythons. They lay about fifteen eggs. The snakes curl up over them, forming a kind of canopy.
- Most of all, birds are similar to reptile embryos, which in the first stage of their development are similar to fish-like creatures with tails and gills. This makes the future chick look like other vertebrates in the early stages of development.
Differences between birds and reptiles
When paleontologists study the origins of birds, they compare facts and finds, collected bit by bit, and find out how birds are similar to reptiles.
What are their differences, read below:
- When the birds got their first wing, they began to fly.
- The body temperature of birds does not depend on external conditions, it is always constant and high, while reptiles fall asleep during cold weather.
- In birds, many bones are spliced; they differ in the presence of a tarsus.
- The birds have air sacs.
- Birds build nests, hatch eggs, and feed chicks.
Firstbirds
Fossil remains of ancient birds have now been found. After careful research, scientists came to the conclusion that they all belong to the same species that lived one hundred and fifty million years ago. These are Archeopteryx, which means "ancient feathers". Their difference from today's birds is so obvious that Archeopteryx were singled out into a separate subclass - lizard-tailed birds.
Ancient birds have been little studied. General characteristics boil down to determining the appearance and some features of the internal skeleton. The first bird was notable for its small size, about the size of a modern magpie. Her forelimbs had wings, the ends of which ended in three long toes with claws. The weight of the bones is large, so the ancient bird did not fly, but only crawled.
Habitat - coastal areas of marine lagoons with dense vegetation. The jaws had teeth and the tail had vertebrae. No connections have been established between Archeopteryx and modern birds. The first birds were not the direct ancestors of our birds.
Importance and protection of birds
The origin of birds is of great importance in biogeocenoses. Birds are an integral part of the biological chain and participate in the circulation of living matter. Herbivorous birds feed on fruits, seeds, green vegetation.
Different birds play different roles. Granivores - they eat seeds and fruits, some species - store them, transferring them over long distances. Seeds are lost on the way to storage. This is how the resettlement of plants occurs. Some birds have the ability to pollinate them.
The role in nature is great. They control the number of insect populations by eating them. If there were no birds, the destructive activity of insects would be irreparable.
Man, as far as possible, protects birds and helps them survive in severe winters. People hang temporary nests everywhere. They are inhabited by tits, flycatchers, blue tits. Winter periods are characterized by a lack of natural bird feed. Therefore, the birds should be fed, filling the nest with small fruits, seeds, bread crumbs. Some birds are commercial species: geese, ducks, hazel grouses, capercaillie, black grouse. Their value to humans is great. Woodcocks, sandpipers, snipe are of sports interest.
From time immemorial: the body and legs of Archeopteryx were covered with long feathers, three and a half centimeters. It can be assumed that the bird did not swing its legs. Feathers were inherited from ancestors who lived in more ancient times and used all four wings during flight.
Today: filling the nesting place of birds with food, you need to make sure that no salt gets there. It is a white venom for birds.
Goal:
- Find and show similarities in the organization of birds and reptiles, discuss hypotheses about the origin of birds from ancient reptiles, the formation of ecological consciousness.
- Form students' general educational skills and abilities using the lesson material.
Tasks:to form ecological consciousness: human ecology and environmental ecology. Students need to master the basic knowledge and skills of preserving biological diversity and protecting birds, protecting the environment.
Personal: to teach students to establish links between the purpose of educational activity and its motive; to form cognitive interests and motives aimed at studying wildlife; intellectual skills (to prove, reason, analyze, compare, draw conclusions, etc.); aesthetic attitude to living objects
Regulatory: definition of the purpose of the work, the plan for its implementation; control and correction of material assimilation; mastering the components of research activities, including skills: (to see a problem, put forward hypotheses, give definitions to concepts, classify, observe, draw conclusions and conclusions, structure material, explain, prove, defend your idea)
Cognitive: compile tables, compare biological objects; establish links between structure and lifestyle (adaptation of birds to flight), find biological information in various sources (textbook text, popular science literature, biological dictionaries and reference books), analyze and evaluate information, transform information from one form to another;
Communicative : ability to adequately use speech means for discussion and argumentation of one's position, to compare different points of view, to argue one's point of view, to defend one's position; learn to listen and engage in dialogue, work in pairs.
Equipment: The skeleton of a bird and a reptile, tables "Origin of birds". “Type Chordates. Bird class. Dove". Digital microscope, handouts (chicken legs, bird feathers, tortoise horny scales, egg shells). Wet preparation of lizard, snake. Laptops. Presentation .
Part 1: Checking homework. 10 min.
Knowledge check on questions:
What are the features of the annual life cycle of birds? What birds are called migratory? What is the biological significance of bird migration? How is bird migration studied?
What is the difference between the lifestyle of sedentary birds and nomadic ones?
What sedentary, migratory and nomadic birds live in the Moscow region?
It is proposed to build a diagram containing the main stages of the life cycle of birds:
Possible student records in circles: reproduction, ritual behavior, nest building, incubation. Caring for offspring. Preparation for winter, wintering, migration. The meaning of birds. The origin of birds. Who completed the task correctly, put a plus next to it.
I bring the students to the conclusion: birds have a more complex organization, which manifests itself not only in their structure, but also in their annual life cycle. I ask you to write down biological and concepts: sedentary birds, nomadic birds, migratory birds and explain how they understand the terms: "invasion", "introduction", "synanthropus", anthropogenic environmental factors, ecology. How do you understand the term environmental awareness?
Part 2: Learning new material 25 min.
Frontal work with the class (5 min.)
- How the structure of birds differs from the structure of reptiles - we compare it according to the table.
- What are the similarities between birds and reptiles: in the external structure, in the structure of the skeleton, systems of internal organs, reproduction and development? (skeleton models used, egg shells)
- What are the similarities between birds and reptiles?
Formulate the topic of our new lesson, think over the purpose of the lesson. How are environmental ecology and human ecology interconnected, the past, present and future of our planet? Today we are going to get acquainted with various hypotheses about the origin of birds.
For the addition and answers I give pluses and ratings.
I make a generalization: indeed, many signs indicate the relationship of birds with reptiles. Both have dry skin, devoid of glands, many cutaneous horny formations: horny shields and claws on the legs, horny sheaths on the jaws. Feathers develop from the same epithelial buds as the horny scutes of reptiles. There are also great similarities in the embryos of birds and reptiles (egg structure). Birds have especially many common features with small ancient reptiles - thecodonts, who lived about 200 million years ago.
Working with the textbook (5 min.)
To clarify the structural features of the first bird, it is proposed to read the section of the textbook page 99 - additional information, consider Figure 189 and fill out the table (Find at least 3 signs) ( Appendix 1
).
(we check and evaluate the work - 2 students) 2 pluses for the table completely filled.
Practical work (10 min.)
Let's check the information in the table by conducting laboratory tests. On the tables, you have instruction cards and research material, do the work in pairs. ( Appendix 3 )
Working with printed material (5 min.)
You have materials on the origin of birds on your tables. Get acquainted with the presented hypothesis. Emphasize what you agree with and what you do not understand or doubt. Present your arguments for the origin of birds from reptiles or against, express your point of view. On the blackboard table:
| The origin of birds from reptiles | ||
| Arguments for | Arguments against | doubt |
Part 3 Generalization of the material. 10 min.
The first bird is an ancient primitive bird, much like a reptile. She is able to run on the ground on two strong legs, climb tree branches using elongated clawed fingers located on the wings. It should be noted that this bird did not fly well, but could glide, covering short distances, thanks to its wings and a long, wide tail.
We tried to find out who is the possible ancestor of birds. You got acquainted with different hypotheses, but maybe your future research in this area will bring some new theories about the origin of birds. At the moment, your task is to preserve for your descendants the diversity of birds that is now on Earth, and for this you need to know more about your environment, what birds are next to you, and for this you need to form ecological consciousness. What do you think, can the anthropogenic factor be decisive in reducing the biological diversity of birds on the planet?
Let's remember the birds living in Moscow and the Moscow region. As a person, you guys can help preserve the birds of your land. Suggest bird protection measures. An irreconcilable fight against the destruction of bird nests, collecting eggs, destroying birds with slingshots, frightening birds from the nest. Measures for attracting birds: preparing food for them, making and installing feeders. Hanging nesting and birdhouses.
State reserves, including ornithological ones, play an important role in the system of nature protection in our country. They carry out a lot of work to study the biology and protection of birds. More than 200 birds are listed in the Red Book of the Moscow Region. (Decree of the Government of the Moscow Region dated February 13, 1997 No. 11/4 "On the establishment of the Red Book of the Moscow Region")
I suggest that you get acquainted with some representatives of birds, think over a project plan for the conservation of this species.
Search for possible new nesting sites for eagle owls and the organization of specially protected natural areas here. Regulation of the number of wild boar and stray dogs in the nesting areas of the species. Promotion of the need to protect the species among hunters and the local population.
Grades for work in the lesson and additions (2-3 students)
Assignment for home: P.50, questions # 5.6 pis. Create a project for the conservation of rare birds: one bird species from the Red Data Book of the Moscow Region (optional)
Introspection lesson.
Lesson type: traditional in the system-activity paradigm with the posing of problematic questions. In the lesson, basic, corporate and personal values \u200b\u200bare formed through the content of the lesson, such as environmental awareness, human ecology and environmental ecology, citizenship, kindness. Respect for nature, protection of rights and responsibility.
In the lesson, UUD are formed according to the Federal State Educational Standard (listed at the beginning of the synopsis):
- comparison (analysis and synthesis), terms: synanthropes, sedentary, nomadic and migratory birds.
- ability to analyze
- ability to simulate (compile tables)
- work with practical material (research activities), work with a computer and a digital microscope.
- formation of competent speech: formulating hypotheses and putting forward arguments for and against, working with various types of text
- ability to correct material
- work in pairs
12-15 marks per lesson.
Appendix 1.
Filling the table.
Similarities between the first bird and birds and reptiles.
Appendix 2
Laboratory research
Confirmation of the table data in laboratory studies using a digital microscope:
Instructional card number 1
1. View the feather structure of a bird at 10 * and 60 * magnifications, overhead lighting.
2. Find the main parts.
3. Take photos
- Bird feather structure 60 *
- Ochin, fan, rod, barbs.
5. Save the drawing in your folder under the name "Origin of birds".
Instruction card number 2
1. Examine the structure of the skin on the tarsus of a bird at 10 * and 60 * magnification, top lighting and the horny scales of the tortoise shell.
2. Determine what the legs and toes of the bird are covered with, and what kind of body cover the reptiles have.
3. Take photos
4. In the Paint editor, complete the captions:
- Horny formations of a bird 10 * 60 * and
- Horny formations of reptiles 10 * .60 *
Instruction card number 3
1. Look at the structure of a bird's egg shell at 10 * and 60 * magnifications, overhead lighting.
2. Determine how important such an egg structure is for the development of an organism on land.
3. Take photos
4. In the Paint editor, complete the captions:
- Egg shell 10 * 60 *
5. Save the drawings in your folder called "Origin of Birds".
After completing independent work, we check how it was done. Add data to the comparison table. I invite students to make a presentation in the next lesson. Make a presentation: 4-5 slides: Archeopteryx.
Instruction card number 4
1. 1st slide - the title of the presentation. Who made it up.
2. 2nd slide - Similarity to birds.
3. 3rd slide - Similarity with?
4. 4th slide - Similarity with?
5. Save the presentation in your folder called "Origin of Birds".
Show 1-2 graded presentations (2 students)
1. What is the role of herbivorous birds in natural ecosystems?
Herbivorous species feed on fruits, seeds, vegetative parts of plants. The role of different birds of this group in natural communities is different. Granivorous birds eat a lot of seeds and fruits of plants. Sometimes they store fruits and seeds, sometimes they carry them over considerable distances. Losing them, they contribute to the dispersal of plants. Small tropical birds - hummingbirds and sunbirds pollinate plants.
2. Tell us about the importance of insectivorous birds in nature.
They play an extremely important role, eating many insects, regulating their numbers in natural communities. Insectivorous birds render a great service to humans, destroying pests in gardens, squares and parks. They reduce the damaging effect of insects on plants in planted forests, forestry and in fields, orchards and vegetable gardens.
3. Name two or three species of game birds. Where do they live, what kind of life do they lead?
Geese and ducks; chicken birds; hazel grouse, black grouse and wood grouse. They live in Siberia, Europe, on the coasts of the Far North.
4. Describe two or three breeds of poultry. What products do you get from them? Where and how are they bred? .
Domestic ducks occupy a significant place among farm birds. They were bred from the mallard duck, which is widespread in Eurasia and North America. Ducks are bred near reservoirs. The most widespread are the breeds of Peking ducks, Moscow whites, and Ukrainian.
- Chickens are bred for meat, eggs and feathers. There are fighting roosters and decorative chickens. In the process of domestication, the productivity of chickens increased significantly.
- Turkeys were domesticated by Indians in Central America. Domestic turkeys grow rapidly, reaching a mass of 10-35 kg (males) to 5-11 kg (females). They lay 100-150 eggs in one season.
5. What are the main similarities in birds and reptiles.
The similarity of birds and reptiles is noticeable both in the external and in the internal structure. Both have dry skin, devoid of glands, many cutaneous horny formations: horny shields and claws on the legs, horny sheaths on the jaws. Feathers develop from the same epithelial buds as the horny scutes of reptiles. Both have a cloaca - the last section of the digestive system, into which both the ureters and the ducts of the sex glands open. There are also great similarities in the embryos of birds and reptiles.
6. Consider Figure 189. What are the structural features of Archeopteryx? Compare it to a modern bird. What are their differences?
His body was covered with feathers, which even in the smallest detail were similar to the feathers of modern birds. The forelimbs were wings, at the ends of which there were three long fingers with claws. There was no keel on the sternum. The bones were heavy, so it is believed that Archeopteryx did not fly, but climbed branches and could glide, jumping from one branch to another. The first bird grasped the branches not only with the fingers on its legs, three of which, like in modern birds, were directed forward and one back, but also with the fingers located on the wings. The chicks of modern South American birds of the goatzin do the same. "They retain their fingers on their wings.
No connections between Archeopteryx and modern birds have been established. Archeopteryx was not a direct ancestor of modern birds, but was a lateral branch in their evolution. Real birds appeared at the end of the Mesozoic era.
Birds play an important role in natural ecosystems. Herbivorous birds feed on fruits, seeds, and vegetative parts of plants. However, the role of different birds of this group in natural communities is different. Granivorous birds eat a significant part of the seeds and fruits of plants. Many species store fruits and seeds and carry them over considerable distances. Losing them along the way, they contribute to the dispersal of plants. Small tropical birds, for example hummingbird and sunbirdspollinating plants.
The role of insectivorous birds is great. They play an extremely important role in controlling insect populations. In natural habitats, birds consume many insects, reducing their destructive activity. Insectivorous birds play a particularly useful role in gardens, squares and parks.
Therefore, man protects and attracts birds by hanging artificial nests - titmouses, birdhouses, nest boxes (Fig. 187). They are occupied by insectivorous hollow-nesting birds: great tit, blue tit, pied flycatcher.
In the harshest and most feeding periods of winter, birds need feeding. You need to make sure that the bird feeder always has food: seeds and fruits of wild plants, sunflower seeds, crumbs of white bread. If you regularly feed the birds until spring, you can ensure that they stay here to nest. Be careful not to accidentally spill salt on the bird feeder. It's poison for birds!
Hunting birds. Some birds have not lost their importance as game animals. Usually they hunt large birds: from waterfowl - to geese and ducks; from upland game - on hazel grouse, black grouse, wood grouse... Fishing is of great importance for the inhabitants of the northern regions ptarmigan... Sport hunting has long played a role. Hunting for small nimble in flight is associated with purely sporting interest. waders: woodcock and snipe - during their current flights, when they fly over forest glades on a thrust with peculiar sounds in the morning or evening hours. Now, due to excessive fishing (overfishing), the number of sports hunting and hunting birds has sharply decreased.
For the preservation of game, hunting rules have long existed, including regulations on the timing and objects of hunting. Hunting during the breeding season is completely excluded. It is forbidden to hunt for species, the number of which has sharply decreased, for species included in the Red Data Books.
Poultry. The domestication of birds took place in ancient times (Fig. 188). The ancestor of all modern breeds of domestic chickens was one species - banking, or shrub, chickencommon in the forests of Southeast Asia. Domestication occurred in India several millennia BC. Chickens were brought to Europe in ancient times. Chickens are bred for meat, eggs and feathers. There are fighting roosters and decorative chickens. In the process of domestication, the productivity of chickens increased significantly. If wild bank chickens lay 12-15 eggs per year, then modern egg-bearing breeds - 200-300 eggs and are laid almost daily. These are the breeds leghorn, bred in many European countries and the USA, and derived from them russian white... The Leghorns have lost their incubation instinct. Commonly used breeds have been bred, from which both meat and eggs are obtained. They breed in Russia yurlov's vociferous and may Day chickens... The body weight of Yurlov chickens reaches 4 kg, while the bank chicken has a weight of about 800 g.
In poultry farms, chickens are bred on an industrial basis. Large poultry farms operate here, where hundreds of thousands of chickens are kept, from which millions of eggs are obtained a year. When caged, laying hens are on a slatted floor with a slope. The laid egg is rolled out on an inclined chute. After checking, the eggs are placed in special boxes and sent for sale. The poultry farm has incubator (apparatus for artificial breeding of birds from eggs) and a room in which chickens are raised.
Domestic ducks occupy a significant place among farm birds. They were bred from the wild duck mallardwidespread in Eurasia and North America. Ducks are bred near reservoirs. The most widespread are breeds peking ducks, Moscow white, Ukrainian... They grow rapidly and by autumn they reach a mass of more than 2 kg (Fig. 189).
Home geese descended from wild gray goose (European breeds) and from dry-nosed (Chinese breeds). Turkeys were domesticated in Central America. Domestic turkeys grow relatively quickly: turkeys reach a mass of 10-35 kg, turkeys - 5-11 kg. These birds lay 100-150 eggs in one season.
The importance of birds and their protection
Birds are our winged friends. Some birds are more beneficial than others, but there are no useless birds. What are the benefits of this or that bird? What do they eat? How many pests of forests and fields eat and what?
These and other questions can be answered only by observing the life of birds in natural conditions.
Birds are of great importance for forestry, field cultivation, horticulture, and truck farming. Birds are also an object for hunting. And, therefore, it is very important to study the biological characteristics of commercial species of birds. The aesthetic value of birds as beautiful and original elements of nature is also great.
For a long time, the cuckoo was considered a harmful bird, believing that it reduces the population of other birds, throwing eggs from their nests and laying their own. Birdwatching observations have established that the cuckoo feeds on furry caterpillars, which no other bird eats. Since then, the cuckoo has ceased to be considered "harmful", and when you hear the familiar "cuckoo" in the forest, you immediately understand that this forest is not threatened by caterpillars, that it is clean.
Observing migratory birds, ornithologists have established not only the location of wintering and nesting grounds, but also the places lying on their way, favorable for feeding and resting. It was found that many birds perish during the flights. They die from lack of food, storms, at the hands of poachers. Observation points are set up along the bird migration routes. With the help of data from these points, the flight speed of flocks, the number of birds in them, and the time of passage are established. Taking care of the number of birds, in many countries it is forbidden to hunt on the days of nesting and hatching of chicks, during their flight.
Having found out, as a result of observation, that many waterfowl perish from oil spilled by sea vessels, an international treaty "On the protection of the world's oceans" was signed. According to this agreement, scientists monitor the waters and, if an oil slick is found somewhere, they destroy it with the help of chemical reagents, and “dirty” birds soiled with oil are caught, washed, thereby saving their lives and preserving the population size.
Reserves are being created to protect birds.
Observing starlings, ornithologists found that their populations began to decline due to a decrease in the number of trees in the forests in which they nested. And then people began to make houses for them - birdhouses. Now, as a result of observations, it has been established that the number of tits, redstart and pied flycatchers is sharply decreasing, and therefore ornithologists appeal to the population to make houses not only for starlings, but also for small birds and hang them in gardens, parks, squares.
So, observing the behavior of birds, ornithologists answer many questions from their lives, increase their number, can talk about the benefits of birds, instill in a person a love of nature, introduce him to the beauty and mystery of life in the wild world.
