On a hot summer day, high in the sky you can see a beautiful sight: a bird of prey slowly soaring in circles. Her flight seems to last forever. Only occasionally, when necessary, does the bird flap its wings.
The force of gravity, which attracts any object to the ground, also affects birds. Therefore, the bird, by flapping its wings, counteracts this force. Flight requires lift (as described in the article: How airplanes fly), but how does it arise in birds?
Lift occurs in the wings. The wing of a bird is not flat, as it seems at first glance, but has a convex shape in the upward direction. Air, in order to get from the leading edge to the flight wings, must travel a longer distance along the top of the wing than along the inside. The air flow rate on the upper side is higher than on the lower side. Lifting thrust is generated on the upper side of the wing, and pressure is generated on the lower side. They act vertically upward in opposition to gravity. The lifting force, which consists of the traction force and the weight of the bird, depends on the size of the individual and the shape of its wing.
Speed also plays an important role when air flows around the wing, and at what angle the air hits the leading edge of the wing. If this angle changes, then the lift force also changes. If the wings are positioned vertically relative to the air moving towards them, then the flow that flows around the wings, the same one that keeps the bird in flight, will disappear and the bird will end up in an air pocket. This is how the landing occurs.
Penguins and Ostriches. Flightless birdsGoals: repeat the material covered about the internal and external structure of birds and eggs; continue to acquaint students with the structural features and adaptation to the habitat of birds of various orders; teach to recognize studied birds in nature, in pictures, tables; develop attentiveness and ability to speak in front of an audience; cultivate responsibility, initiative, mutual respect; arouse interest in biology.
Equipment: textbook; multimedia projector; photographs of Ostrich and Penguin; tables and visual aids.
Lesson type: learning new material.
Lesson progress
1. The sparrows fluttered onto the fence.
List the characteristics of the class of birds (as a result of a frontal survey, students must name the characteristics and write them on the board)
- Do all birds fly the same?
III. Learning new material
You already know that Birds are the most numerous class of vertebrates living on land. In total there are about 8,600 species of birds.
- Remember the name of the section of zoology that studies birds? (Ornithology.)
Scientists group all types of birds into three superorders: Penguins, Ostriches and Typical birds. Today's lesson is dedicated to Penguins and Ostriches.
Penguins are probably one of the most amazing creatures on earth. Until recently, penguins were a big mystery to researchers. No one could say which group of birds was closest to penguins. This was due to their physiological characteristics, such as wings turned into flippers, as well as a special shape of feathers, the same size and similar to scales. The first penguins appeared 70 million years ago, at the end of the era of dinosaurs. The oldest specimen of a penguin was found in fossils dating back 40 million years. Modern penguins appeared in this form about two million years ago. All penguins lived and live in the southern hemisphere. The only exception is the Galapagos penguin, which is found in Ecuador, which is also the only equatorial penguin. Penguins include 16 living species. In ancient times there were about 36 species of penguins. Penguins are the only birds that walk standing and can swim but cannot fly.
- Does anyone know how penguins got their name? (Penguins had an external resemblance to the great auk; it disappeared in the 19th century. The auk, moving on land, held its body almost vertically, and its wings served as flippers. Scientifically it was called Pinguinus impennis (from English, pin - hairpin and wing - wing ).)
The first Europeans to see penguins were sailors from Vasco da Gama's team. But they decided that they were geese. English sailors, who also saw penguins, but at the end of the 16th century, mistook the penguins for great auks and began to call them penguins, meaning auks. Soon the auks became extinct, and their name remained with the penguins.
Penguins are known for their exceptional adaptation to cold climates. This ability is due to a thick layer of subcutaneous fat and three layers of feathers, which evenly adjoin each other in a tiled manner. For example, with a penguin weighing 38 kg, its body contains 17 kg of fat. It is estimated that 87% of thermal insulation is provided by feathers, and the remaining 13% by fat.
- Why do you think? (Feathers act as fish scales; they also prevent the animal from getting wet and hypothermic.)
Since their wings are not adapted for flight, they are used as fins and, together with the torpedo shape of their body, penguins can develop great speed. However, because of this, they slowly move along the ground, hobbling in different directions. The legs of these birds are moved back, and the wings have transformed into a kind of flippers. Despite the fact that penguins move rather clumsily on land, in water they can reach speeds of up to 30 km/h. In the water, penguins move with the help of flipper wings, and their webbed feet act as rudders. Penguins not only swim well, but also walk quite quickly. The speed does not exceed 1-2 km/h, but the distance that can be covered, for example, emperor penguin, up to 100 km without rest.
Penguins are the world's unrivaled divers. In one breath, the emperor penguin can dive half a kilometer into the depths and stay under water for up to half an hour (usually 6-7 minutes) in search of deep-sea myctophid fish. They feed mainly on small fish and krill, each catching for themselves individually. A huge amount of food is consumed by the penguin colony during the mating season. In studies of Adelie penguins, it was found that adult birds make approximately 40 trips to the sea daily during the feeding period of the chicks, and each time they bring with them about half a kilogram of food. For example, at Cape Crozer, a colony of 175,000 penguins brought almost 3,500 tons of fish ashore for their chicks. And the largest rookery on Cape Adar consists of 250,000 birds.
Penguins are good parents. However, the role of the mother and father is different from most birds, as the father is usually the one who spends most of the time caring for the egg and keeping it warm until the chick hatches. And mothers go hunting to get food for both.
Since penguins are known to be native to Antarctica, which is a very cold place, keeping the eggs warm is very important. Usually, fathers place the egg between their legs and cover it with their belly, which gives the egg the necessary warmth and prevents it from freezing. Fathers usually crowd together so that they themselves do not feel cold. Although penguins live near the ocean, they drink fresh water. They have a special gland behind their beaks that is capable of filtering salt water. They also eat snow and ice because they contain fresh water. Penguins are surrounded by many predators. Some of their main opponents are dolphins and killer whales, so penguins are very careful. Another interesting fact about penguins is that they use sign language to communicate. They shake their heads or flap their wings to communicate something.
Interesting facts from the life of penguins
- Why do you think?
(The structure of the wings does not allow the bird to fly.)
The contour feathers of ostriches are fanned out: they are devoid of hooks, and the beards do not form closed fans. Also, the small sternum of the ostrich does not have a keel. But the long, strong, calloused legs of ostriches allow them to run quickly; birds can reach speeds of up to 70 km/h.
- Ostriches have a small head on a long neck. Why does an ostrich have a long neck?
(To see the surroundings clearly. Helps in catching insects.)
The food of ostriches is insects, small vertebrate plant seeds. There are several species of ostriches: African ostriches, Australian emus, American rheas, cassowaries and kiwis.
African ostrich(Struthio camelus) holds three records! It is the largest, fastest running bird and lays the largest eggs. The weight of an ostrich reaches 160 kg with a height of up to 2.75 meters. Males are heavier and taller than females. The interesting thing is that ostriches are not the largest birds when you consider extinct birds. The giant moa (Dinornis robustus), exterminated by the Maori tribe in New Zealand, reached a height of 3 meters and weighed 250 kg.
The ostrich is the only bird that has only 2 toes on its feet. The nail on the larger one resembles a beak. There is no nail on the second finger. It is believed that the small number of fingers helps the ostrich run so fast. An ostrich can reach a running speed of 70 km/h. He is able to run 20 kilometers without stopping in 15-20 minutes. At full speed, an ostrich's stride length is 5 meters! The ostrich's paws are so strong that it can kill a person with a blow. As a defense, a person can only fall to the ground, but in this case he is in danger of a strong bird's beak. By the way, a baby ostrich can run at the speed of an adult ostrich already at the age of 1 month.
Ostriches can't fly. They use their wings during marriage ceremonies and to protect their children, since the ostrich's wingspan reaches 2 meters.
Ostriches swallow stones and use them to improve digestion. About 1 percent of a bird's weight is ingested stones. It’s the same as if a person swallowed and carried up to a kilogram of rubble inside him. An adult ostrich eats up to 7 kg of food per day. Moreover, ostriches are omnivores - they eat plants and animals - lizards, chicks, turtles and insects - with the same taste. The length of the ostrich's digestive tract reaches 14 meters.
The eggs of other birds seem very fragile and delicate to us. But African ostrich eggs can withstand a mass pressure of 120 kg. These are the largest eggs among all animals - the weight of the egg is 1.5-2 kg, of which the shell weighs up to 300 grams. This is equivalent to 36 chicken eggs. Crocodiles, even weighing a ton, lay eggs no larger than those of a goose. No wonder African Bushmen use ostrich egg shells for storage. drinking water and as vessels.
Ostrich eggs are incubated by males for most of the day, and from many females from the flock at once. However, the main female is responsible for the distribution of eggs - she places her own in the center, and the eggs of other females at the edges. Once in Kenya, an ostrich clutch was found consisting of 78 eggs, of which only 21 were hatched. Such wastefulness has a deep biological meaning: numerous predators first of all pick up the eggs scattered around the nest, without touching those that lie in its center.
Cooking scrambled eggs from 1 ostrich egg can be equivalent to 25 chicken eggs.
Now listen to the reports of your comrades about other species of Ostrich.
Nandu
Rheas live in South America. Rheas grow up to 170 cm. Rheas live in flocks; in September - December, the male takes 2-4 females away from the flock. The courtship of the rhea is peculiar. The males ruffle their feathers, wave their inflated necks at the female and make sounds similar to “nan-doo!” The male himself prepares the nest in the form of a hole covered with grass. One female lays 10-15 eggs in a nest. Usually there are about 20 eggs in the nest, but sometimes there are up to 80. When the eggs are laid, the male rolls them out with his beak and incubates them next to the nest. Only males incubate rhea eggs: at night and in the morning, covering them with their body and wings. Hatching lasts 40 days, but the chicks do not hatch in one day. It happens that the last chicks die because... The male has already left with the other chicks. At the slightest danger, a caring father hides the babies under his wings. By the way, the ostrich needs wings for braking while running and making sharp turns. Nandu runs away from enemies not in a straight line, but in zigzags. It's easier to break away that way. After six months, striped rhea chicks become identical to their parents, and after 2-3 years they change their plumage. The color of the rhea is gray. The head, hips and neck are covered with feathers (African ostriches do not).
Cassowaries
There are 3 types of cassowaries. These birds live in the tropical forests of Australia, New Guinea and nearby islands. The cassowary is a relative of the emu. These birds live alone, not in the steppes, but in dense forests. Cassowaries have black plumage and a high horny crest on their heads. Their neck is tricolor: red, yellow, blue. With its helmet, the bird pushes aside the thickets of plants. Cassowaries feed on small animals, fish, and fallen fruits. The eggs (there are 3-8 of them) are hatched by the male. The chicks are striped. Unlike the rhea, the cousoir has only one female. Cassowaries are loners and very quarrelsome. They are quite aggressive birds and have some formidable weapons on their middle fingers - 10cm long claws. Birds often fight among themselves. The cassowary is capable of jumping 1.5 m from a standstill. Papuans make daggers from the bones of birds, and needles from the bones of their wings. In New Guinea, young cassowaries are caught and tamed to be sold to zoos.
Emu
These birds live in the scrubby sandy deserts and steppes of Australia and Tasmania. Their food is fruits, seeds and small animals. Emu height reaches 1.5-1.8 m, weight 45-54 kg. The bird's legs are very strong, three-toed. The emu is armed with a long, sharp claw on its inner toe. Male and female emus are very similar and difficult to tell apart. The mating season begins at the end of September - October. In January-February, the female leaves the male, laying 10 or more eggs. The female does not take care of the chicks, this is the responsibility of the male. The male emu incubates the chicks for 53 to 66 days. Hatching is not an easy task, the male eats almost nothing, in addition, during the first and last days of the incubation period he does not leave the nest at all. Emus feed on fruits, berries and seeds that have fallen from trees. Before hatching the eggs, the male weighs 50-55 kg; after hatching, he loses up to 16 kg. After hatching, the 400-gram chicks are tenderly cared for by their father.
Kiwi
These smallest ostriches are found only in New Zealand. The birds got their name from the sounds made by the males. By the way, the female kiwi is much larger than the male, and her beak is also much longer. Europeans first encountered kiwi in 1811. Brown kiwis live in large families, but other kiwis are solitary or live in pairs. Kiwi is small (50-80 cm), similar in size to a chicken, but kiwi eggs are 6 times larger than chicken eggs. Therefore, kiwis only lay one egg per year, but brown kiwis are capable of laying 4 eggs per year. Eggs are so large because they are 60-65% yolk. After three 3 months, the chicks hatch from the eggs, they grow quickly, and become independent after 3 weeks of life. Kiwi chicks peck the egg shell from the inside not with their beaks, but with their feet. The kiwi's body is covered with hair-like feathers that look like fur. Kiwi wings are tiny and have a claw at the end of the wing. These birds feed mainly on invertebrates, but also eat berries, mushrooms, crayfish and frogs. Kiwis can live 30-40 years. Kiwis, the only birds in the world, have nostrils located at the tip of their beak. This small bird has a good sense of smell.
IY. Consolidation.
Compare African, American and cassowary ostriches? What do they have in common?
How are they different?
Y. Homework
§ 27.28 (up to Anseriformes). Answer the questions at the end of the paragraph. Prepare a message “The ostrich is the largest bird on the planet”, poems, riddles about penguins and ostriches, interesting facts from the life of birds (optional).
When I see birds soaring in the sky, I am always amazed: “How do they manage to stay in the air?” After all, it is known that there is a gravitational force, which, in theory, should pull them down. Then what is their feature?
Flight - complex process. Of course, its main mechanism is its wings. They are designed in birds in such a way that they are capable of creating a lifting force, which, in turn, resists the force of gravity. This force occurs when the wind hits the wing. But what do birds do if there is no wind?
They actively flap their wings, thereby creating a flow of air that lifts them above the ground. This is the most important stage take-off, thanks to which, having flown upward, the bird can soar without moving its wings.
Of course, in addition to wings, muscles, skeleton, and internal organs. To make it easier for a bird to rise into the air, it should be as light as possible. For this reason, her bones are filled with air. Also, a short intestine promotes rapid elimination of food, which lightens the weight of the bird.
If we can still somehow guess about the reasons for the flight process, then how can we explain why most large birds fly in a wedge? It's amazing how synchronously and harmoniously they do this.
As it turns out, they choose this arrangement in order to save energy. The first bird sets the air flow, and the subsequent ones, roughly speaking, take advantage of this - they pick up this flow and, thanks to synchronized movements, make their flight easier.
So, what does a bird need to fly:
Not all birds have all these qualities; accordingly, they are deprived of the ability to fly. For example, penguins and ostriches certainly do not fall under the last point.
There are birds that stopped flying in the process of evolution due to the fact that the need disappeared. They had no one to fly away from; there were no enemies in the surrounding nature. Now they are on the verge of extinction. Among them, for example, is the kiwi bird.
While working on the “Secrets of Birds” project, we decided to find out whether all birds fly and why some of the birds have lost the ability to fly. After viewing this presentation, you can get acquainted with flightless birds and find out why they cannot fly.
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Project: “Do all birds fly? Why can't some birds fly? Head: teacher primary classes MBOU - Poluzhskaya secondary school Pinchukova Elena Fedorovna. Performers: 3rd grade students
Flightless birds do not have a keel, a growth on the sternum to which powerful muscles responsible for flight are attached. All flightless birds have either a very small keel or no keel at all. For this reason, their wings are weak, and the birds are not capable of flight.
Ostriches are the largest birds living on Earth. Some of them reach a height of 2.7 meters. Ostriches live on the open plains of Africa. Ostriches feed on seeds, fruits, as well as lizards and insects. Ostriches cannot fly, but they run fast. Over short distances they can reach speeds of up to 70 km/h.
Emus are large flightless birds living in Australia, they reach a height of 2 m. These birds feed on seeds, fruits and insects.
So why don't ostriches fly? Here's why! They are too big, a bird can fly if its mass does not exceed 20 kg, and ostriches weigh 120 kg.
This is interesting! One ostrich egg is equal to 40 chicken eggs and can support the weight of a person.
Penguins are flightless birds. There are 18 different species of penguins. They live only on the coasts of the seas of the Southern Hemisphere - on islands off the coast of Australia, New Zealand, South Africa and the southern part of South America. Penguins are excellent swimmers; they can move in the water at a speed of 30 km/h. Those penguins that live among snow and ice do not build nests.
The emperor penguin is the largest of the penguins. His height is about 1.2 meters and his weight is about 75 kg. When the female lays an egg, the male protects it from contact with the ice by placing it on his own webbed feet. When the chick hatches, the male, having eaten nothing for two months of incubation, goes in search of food, while the female remains with the chick to feed and protect it.
The jumping penguin is so named because it jumps very deftly from rock to rock. Its most noticeable difference is the long crest on its head. Newly hatched Leaping Penguin chicks are covered in soft down. They are helpless, and their parents have to feed and protect them for several weeks.
The donkey penguin makes a sound similar to the cry of a donkey. It is also known as the black-footed penguin.
King penguins live in Antarctica. They can slide on their stomachs on ice at high speed to escape from enemies.
Why don't penguins fly? Penguins used to fly, but more often, hiding from enemies, they hid under water, and gradually their wings lost their feathers and turned into fins.
But that’s not all that these birds can surprise us with. We eat three times a day, but penguins can go without eating for up to three months. A person cannot live without air, and penguins can go without breathing for almost 18 minutes. How interesting!
The kakapo, or owl parrot, is the only parrot that has forgotten how to fly. He lives only in New Zealand, he had no enemies around and did not need to hide or fly away. Kakapo lives in burrows. He spends the whole day in them and only after sunset leaves there to go in search of food - plants, seeds and berries.
The little Kiwi bird also lives in New Zealand and is protected by the state. She has no wings at all.
Kiwi is a small and shy nocturnal bird. The kiwi has an excellent sense of smell, and its nostrils are located at the end of its long beak. Kiwis stick their beaks into the ground to find food.
The Tristan rail, which lives on Inaccessible Island, is the smallest flightless bird in the world. Its length is only 17 cm and its weight is less than 30 g.
So, let's conclude: there are flightless birds on earth. But why don't they fly? 1. They are large in size and body weight. 2. Because of predators, birds swam more than they flew. 3. There were no predators and birds had no need to fly.
Lesson type: general Educational goals: Expand the understanding of wintering birds. Form the concept of wintering birds. Clarify and activate vocabulary on the topic, learn to answer questions...
For an extracurricular activity for Bird Day. "Miracle - Birds"
This presentation was compiled for Bird Day. It can also be used in lessons about the surrounding world in elementary school....
