Bird feather under a microscope. Abstract of GCD in the senior group Topic: “Experiments and experiments with bird feathers

American scientists, intrigued by the deep black color of the feathers of some species of birds of paradise, studied their structure under an electron microscope. It turned out that the black color is not due to pigments - melanins - as is usually the case in birds. It's all about the structure of the feather barbs, at the ends of which there is a “fringe” of nanogrowths. This structure perfectly absorbs light - up to 99.95% of the visible spectrum, which leads to a very rich black color. In terms of absorption, bird of paradise feathers are close to Vantablack, the blackest known material.

In living nature, color can be formed in two ways - pigmentary and structural. In the first case, it occurs due to special molecules - pigments, which selectively absorb, reflect or emit light with a certain wavelength. In the second case, the color depends on the structure of the surface on which the light falls and which selectively absorbs and/or reflects it. Structural coloring is described in detail in the article by T. Romanovskaya. A particular variant of structural coloring is structural absorption, that is, the absorption of light by a surface. If all or almost all of the visible spectrum is absorbed in this way, a black color is obtained.

Black plumage of birds

In most birds, the black color of plumage is due to pigments - melanins. They are responsible for the blackness of birds well known to us - crows, rooks, blackbirds, etc. In addition, in some birds, due to the correctly ordered fibers of the upper layer of keratin, iridescence occurs (a variant of structural coloring). Iridescence is expressed in iridescent tints and/or metallic luster.

“Elements” is already about the unusual behavior of males of the wonderful bird of paradise. When courting a female, the male folds his wings and spreads his feathers so that he ceases to look like a bird at all (Fig. 1, g)! Experienced observers have noticed another feature of this and a number of other species of birds of paradise (family Paradisaeidae). The black color of their plumage visually appears darker (blacker) than the black plumage of other birds (Fig. 1). Recently, a group of scientists from the USA confirmed this observation and, most importantly, figured out how this effect occurs. To do this, the researchers studied the black feathers of seven species (all depicted in Fig. 1) - six species of birds of paradise and one species - Melampittidae - from a closely related family (Melampittidae). Melampitta and paradise crow have black coloration due to melanins, that is, their black color is quite normal. And the rest of the birds of paradise in the study have “super black” batches of plumage. They are typically used in mating displays. Some species, such as the wonderful bird of paradise, have regular melanin black feathers in addition to super black feathers. They are located on the back and during mating the male does not specifically show them to the female. Scientists studied not only the super-black feathers of this species, but also ordinary ones taken from the back.

To begin with, the feathers were studied using a spectrophotometer and a deuterium-halogen light source DH-2000-BAL from Ocean Optics. This source, thanks to deuterium and halogen lamps, as well as special filters, can, in particular, produce output light of a given intensity, which equally represents the entire visible spectrum. This avoids distortions in the spectra of the samples being studied, since they are illuminated by a balanced light beam.

Spectrophotometry has shown that the super-black plumage reflects only 0.05–0.31% of light (that is, absorbs up to 99.95% of the visible spectrum). And ordinary black feathers (paradise crow, melampitta, and those taken from the back of the wonderful bird of paradise) reflect one or even two orders of magnitude more: 3.2–4.7% of radiation (Fig. 2).

These values ​​indicate that the light absorption capacity of the super black feathers of birds of paradise is close to artificial materials with very high degree absorption. Thus, the blackest material available today absorbs 99.965% of visible light. Vantablack consists of vertically oriented carbon nanotubes, and absorption occurs due to the fact that light penetrates into the material, where multiple reflections occur from the walls of the nanotubes.

In addition to the feathers of birds of paradise, the wings of some butterflies absorb light well. Absorbing up to 98-99% of visible light, they also appear very black. This is due to the special microstructure of the scales. (Recall that the wings of butterflies are covered with small scales that overlap one another like tiles.) Super black scales of a male butterfly Troides aeacus from the sailboat family (Papilionidae, Fig. a) they consist of an upper anti-reflective part and a thin film underneath it. Top part consists of evenly distributed Λ-shaped ridges. The ridges are connected to each other by bridges - veins. The result is a lattice with elongated holes measuring about 490 × 380 nm (and a diagonal of about 620 nm, Fig. c-e).

Since the wavelength of visible light falls in the range of 380-780 nm, the holes are sized to allow most of the visible light to pass through. Photons of light “enter” the holes and are reflected from them many times. Light with a longer wavelength is reflected mainly from the ridges, since it cannot pass inside the holes. Repeated reflection leads to absorption of light - just like in the case of Vantablack.

To deal with unusual features black plumage of birds of paradise, scientists used raster electron microscope. As is known, bird feathers consist of a shaft from which first-order barbules extend, from which, in turn, second-order barbules extend (see Shaft, barbs and hooks). The beards of the first and second orders are located more or less in the same plane, forming the fan of the feather.

It turned out that the super-black feathers of birds of paradise have a special structure of second-order barbs. First of all, the tips of the second-order barbules diverge into many microprotrusions that form a fringe (Fig. 3). There is one more feature: the barbs of the second order are, as it were, raised above the plane in which the shaft of the feather and the barbs of the first order are located. As a result, they form a dense (due to microgrowths) layer, rotated approximately 30° towards the tip of the pen.

The layer of tiny nanogrowths is responsible for absorbing light. The fact is that the cross section of microgrowths is less than the wavelength of light. This allows light to penetrate into the pen. Thus, part of the light hitting the pen is absorbed, and part penetrates inside, but almost nothing is reflected out. Inside the feather, photons of light are again reflected, and some of them are again absorbed. Due to large quantity Microgrowths undergo multiple reflections, and each time some part of the light is absorbed. This results in the feather absorbing most of the light. In general, the absorption principle is the same as that of Vantablack.

Due to this structure of the feather, in general, it does not matter what pigment color it has. After all, virtually all the light is absorbed anyway. Researchers have confirmed this in an original way: Covered the feathers with gold dust. The ordinary black melapitta feather (the black color of which is due to melanins) became golden after this operation. But nothing happened to the super-black feather: it remained black, absorbing most of the visible light (Fig. 4).

Interestingly, in birds of paradise, as in butterflies, super black areas are often adjacent to very dark spots. bright colors, as if shading them. Based on this observation, scientists suggested that the super black color evolved to highlight the bright parts of the plumage. And those, in turn, can play a role in mating behavior. For now, however, this is only a hypothesis.

How does a pen work?

The theory of evolution, which states that birds evolved from reptiles, cannot explain the enormous differences between these two classes of living beings. Birds, with their skeleton consisting of hollow and weightless bones, their lung system, their warm-blooded metabolism and other similar features, are very different from reptiles. And one more property that creates an insurmountable gap between birds and reptiles is feathers, which are unique to birds.

Protein-based feathers are made from a substance called keratin. Keratin is a strong and durable material formed as a result of the death of old cells that are located in the lower layer of skin tissue and die, moving away from sources of nutrition and oxygen and making room for young cells.

Bird feathers are designed to be so complex that it cannot be explained by the evolutionary process. Renowned ornithologist Alan Feducchia notes: "Everything distinctive features feather is that it has aerodynamic properties. Feathers are light, have the power of lifting and easily return to their previous shape." And Feducchia reacts to the failures of the theory of evolution as follows: "I cannot understand how such an organ, which was originally conceived and planned for flight, could have originally appeared for other purposes." .

This pen device also made Darwin think. In his own words, extraordinary beauty created peacock feathers for him headache. In a letter to his friend Asa Gray dated April 3, 1869, Darwin writes the following:

"I have lost interest in my own theory because I always think about the eyes on peacock feathers. Over time, I came to terms with this problem. Currently, I am very worried about some devices in nature, the existence of which we had not noticed before. I, for example, come to confusion when I see a peacock feather.

FEATHERS AND HOOKS
If you examine a bird's feather under a microscope, it becomes clear how unusually it was conceived and executed. In the middle there is the well-known long and hard tube. And on both sides of this tube there are hundreds of small feathers. It is the varying degrees of softness and varied sizes of these feathers that underlie the aerodynamic properties of the bird. However, what is most interesting is that on each of the feathers there are even smaller and invisible fibers called fluff. There are small hooks on this cannon. Thanks to these hooks, each fluff is, as it were, connected to each other with a zipper. To better explore this magnificent creation, consider a crane feather. One feather has 650 thin feathers on both sides of the tube, and on each of these feathers 600 feathers are randomly arranged. All these fluffs are connected to each other using 390 hooks. And the hooks are fastened on both sides, like in a zipper. The fluffs are pressed so tightly against each other by these hooks that they don’t even allow air to pass through. If the hooks somehow become separated from each other, then the bird only needs to shake itself or, in the worst case, clean the feathers with its beak to return them to their previous state.

In addition, birds, by fluffing their feathers, do not allow their body temperature to decrease. In hot weather, the feathers, pressed tightly to the body, do not allow the heat to pass through.

Lyudmila Maksimova
“How do bird feathers work?” Summary of experimental activities with children of senior preschool age

Integration of educational areas

Cognition:

Establish a connection between the structure of a feather and lifestyle

Introduce the structure of the flight and down feathers

Form an idea about harmful influence on waterfowl birds pollution of reservoirs, rivers, seas with oil

Artistic word:

Develop in children creative imagination, skill see characteristic features objects and compare them.

Health + physical culture:

Promote the development of fine and gross motor skills

Prevent children from becoming tired.

Communication + socialization:

Expand emotional sphere children.

Develop the ability to interact with adults and children

Cultivate goodwill and compassion for birds who are in trouble.

Develop independence.

Safety:

Follow the basic safety principles when organizing experiments.

Methods and techniques:

Sociogame situations

Artistic word

Productive activity

Experiments

Preliminary work:

Games “Describe bird»

Looking at illustrations

Drawing birds

Modeling birds

Development organization environment:

1. Box for laboratory research

2. Flight feathers, downy, wings

4. Scales, lightning

5. Feather, wing, flight patterns birds, tails

6. Pipettes, container with water, vegetable oil, paper wing

7. Magnifying glasses, wire, brushes, napkins

8. Scissors, oilcloth

10. Gouache, silhouettes birds in flight

11. Colored feathers

1 part. Introductory.

The teacher brings in a box for laboratory research (reads to children)

What do you think is in the box? (shaking, sniffing). I'm asking a riddle

“It flew through the forest, dangled in the water.

It fell into the water and became dry.”

Children guess - feather.

I open it and show it. Yes, it’s a feather.

Whose feather is this?

What role do you think they play? feathers for birds. Let's try to find the answer.

To do this, we need to go to the laboratory of Professor Znayka. (Owl symbol) and explore how the pen is arranged.

The children sit down at the tables.

What is the difference birds from animals? Of people?

They can fly.

I put the plumage diagram on the board birds.

Because all bird covered with a huge number feathers. Birds, the only ones on earth who have feathers.

Why do they fly? birds?

They have wings (schemes of wings, flight)

Showing wings from different birds.

Are they the same? (birds of different sizes, pen color is different)

Now look at your wings, which Professor Znayka prepared for you for research.

Looking for differences (color, differences)

Find the longest feather.

This feather is called "fly". These feathers located along the edges of the wings.

We are considering.

Touch the feather. What is it like? (dense, hard, large)

Let's examine with our fingers.

I wonder if it's light or heavy?

Children put a feather on one hand and a stone on the other.

They conclude that it is easy.

We weigh on the scales - a feather, a stone, two feathers.

We draw a conclusion.

Toss the feather. What do you see?

It falls slowly, spinning smoothly.

Why is it light? The rod is empty.

Cut off the edge of the feather - we see emptiness (you can try inserting colored wire to check for emptiness.)

That's why it's light, the core is empty. Wave the pen, what do you feel?

When bird flaps its wings, the feather springs elastically without releasing the hairs.

Let's see the feather (fan) through a magnifying glass.

You see on the grooves of the feather there are protrusions and hooks that connect firmly and easily, fastening the surface of the feather, and if they come loose, then the bird connects them with its beak.

(pen diagram,)

Experience with lightning.

We confirm that this is a feather "fly"

And what you still have feathers?

Downy (small, fluffy, thin, hairs are not interlocked, the shaft is thin).

We superimpose and compare with the flywheel (we run it along the hand - soft, fluffy)

Why such a feather bird?

The down feather serves bird to keep warm. They are found on the body, head, wings, and paws.

I wonder which feather is lighter - the feather feather or the flight feather?

Let's blow - which one will fly away faster - downy or flywheel?

Finding down ones feathers on the wings.

- Feathers on the tail are called "steers". they help change the direction of flight.

Tail diagrams.

So why birds feathers?

They help you take off, stay in the air, and protect you from bruises, drying out, and getting wet.

Why do you think waterfowl feathers don't get wet? Because they have a special fat gland and birds they lubricate themselves with their beaks feathers.

Let's do an experiment.

You have a paper pen, apply grease (vegetable oil, and Now drop water with a pipette. The water rolls down like this bird feathers It’s not for nothing that the proverb says "Like water off a duck's back".

Guys, what could happen to birds, if unexpected pollution of water bodies, rivers, seas with oil occurs (this is a viscous, thick, black fuel). It is transported on large ships in containers and accidents occur and oil spills on the water.

They may die (picture)

Because birds those caught in an oil spill contaminate themselves feathers. They stick together and lose their ability to repel air. AND birds die.

We are conducting an experiment.

Spilling oil into a container of water (vegetable oil, painted black, throw in a feather)

The feather became heavy, the hairs stuck together.

We must protect nature in order to birds We didn’t find ourselves in such a situation.

Where in everyday life can we use a pen?

Previously, there were no pens; people wrote with a pen. (picture)

Can be painted feathers for crafts(showing in color feathers) .

They decorate hats and clothes.

Pooh pillows are stuffed with feathers, clothes, jackets (light, warm).

Can you draw? Let's try.

Outline the silhouette birds in flight(gouache).

What did we learn about today in Professor Znayka’s laboratory?

How How bird feathers work and their purpose.

- Birds take care of their own every day feathers, carefully clean their plumage, remove foreign objects, wipe off fat and periodically change excess feathers.

ABOUT we know a lot about birds,

And at the same time it is not enough

And everyone needs: both for you and for us,

So that there are more of them.

For this we will save

Your feathered friends,

Otherwise, we will reduce it to zero

Our winged singers,

Eat trees and fruits

Insect larvae.

And all the gardens will thin out

Without ours familiar birds.

Summary of GCD in senior group

Topic: “Experiments and experiments with bird feathers”

Tasks:

O.O. " Cognitive development»:

expand and consolidate ideas about birds, the importance of feathers in the life of birds;

Encourage children to carry out basic experiments, develop the ability to observe and draw verbal conclusions.

O.O. “Social and communicative development”:

continue to teach children how to interact with peers.

O.O. " Speech development»:

practice using comparisons, selecting definitions and antonyms. expand children's active vocabulary (“mA hovoe", "fluff"O voe", "boronO dka").

O.O. “Artistic and aesthetic development”:

learn to create an image of what you see;

develop in children an interest in music and a desire to listen to itand imitate the sounds of birds with the help of musical pieces.

O.O. “Physical development”:

development fine motor skills hands

Materials for the lesson:

Research kit: (flight and down feathers, stones, scales, zippers, pipettes, container with water, vegetable oil, paper wing, magnifying glasses, wire, brushes, napkins, scissors, oilcloth). Microscopes.

Org. moment : children enter the group and see bird tracks

and feathers. –

Who left traces? (birds)

How did you guess? (by tracks and feathers)

What do we call the birds that winter with us? And the ones that fly in and out from us? Name the migratory (wintering) birds.
Guys, why do birds fly to warmer climes?

What birds could have left tracks and feathers today? (wintering). Why?

- Can animals that walk on two legs be called birds?(No. Humans also walk on two legs, but dinosaurs used to walk.) Why?

Can animals that eat grains be called birds?(No, many animals eat grains - rodents, horses.)

Can animals and insects that fly be called birds?(Which ones have wings?) (No. In addition to birds, butterflies, beetles, mosquitoes, and bats fly.)

Can animals and insects that lay eggs be called birds?(no. In addition to birds, all insects, worms, turtles, snakes lay eggs)

Can animals that have a beak be called birds?(No, some animals also have a beak, for example the platypus.)

So what do birds have that no other animal has?

After some thought, the children independently come to the conclusion that the named animal species do not have feathers.

Right. After all, Birds also have a second name: Feathered Ones. Nobody except birds has feathers.

This distinguishes them from other animals and insects. (Feathers)

But what interesting feathers are, what different ones, I propose to study them in our laboratory.

Main part.

Experience No. 1. - Touch the feather. What is it like? (dense, hard, large) - I wonder if it is light or heavy? Children put a feather on one hand and a stone (lung) on ​​the other.

Experience No. 2 Toss the feather. What do you see? (falls slowly, smoothly spinning). - Why is it light? (rod empty)

Experience No. 3 Cut off the edge of the feather - we see a void (you can try inserting colored wire to check the void.)

That's why it's light, the core is empty.

Experience No. 4 "How the pen works"

Wave the pen, what do you feel? (Air) - When a bird flaps its wings, the feather elastically springs without releasing the hairs. These feathers are called flight feathers.

Let's look at a feather under a microscope.

Seeunder the microscope, we discover a stunning sight.

The teacher offers a picture of a feather under a microscope.

As we all know, there is a shaft in the middle of the pen. There are a lot of little barbs coming out of each side of the shaft. Beards of varying softness and sizes. Moreover, a huge number of small, small burs are attached to each beard.O daughters that can only be seen under a microscope. These barbs are held together by means of hooks.The hooks are easily connected, fastening the surface of the feather, and if they disengage, the bird uses its beak to connect them.

Repeated viewing of the pen under a microscope, comparing what is seen in the picture with the image in the microscope.

Once upon a time, very attentive people saw this and invented the zipper.

Experience No. 5 with lightning and fly feather.

What other feathers do you have?

PoohO high (small, fluffy, thin, hairs not interlocked, thin shaft).

Feather comparison

Apply fluffO howl feather on mA hovoe and compare by size. Which one is bigger?

Then we move the down feather along the hand - soft, fluffy. -Why do you think a bird needs such a feather? (Down feathers serve the bird to retain heat. They are found on the body, head, wings, and paws).

I wonder which feather is lighter - down or flight feather? “Weigh” it on your palms, then blow on the feathers. (Children are blowing - which one will fly further - downy or fly?)

Why do you think waterfowl’s feathers don’t get wet? Because they have a special fatty gland and the birds themselves lubricate their feathers with their beaks.

Let's do an experiment.

Experience No. 6

You have a flight feather, drop some water on it. Water rolls off the feathers of birds like this. It’s not for nothing that the proverb “Water off a duck’s back” says. That's why the feathers don't get wet!

What did we learn about in the laboratory today? - About how bird feathers are arranged and their purpose. Having examined feathers in our laboratory, we can conclude - why do birds need feathers? (Help the bird take off, stay in the air, protect it from getting wet, keep it warm)

Birds take care of their feathers every day, thoroughly clean their plumage, and remove dirt.

Now I will tell you something interesting. A long time ago, people wrote with pens because there were no pencils, etc. then.

Let's try to do this too: draw beards on the feathers with a pen.

Conclusion: Today we did a lot of experiments with feathers. We learned a lot about birds. Next time we will meet at the bird feeder and find out what the birds that stay with us for the winter most like to eat.

The theory of evolution teaches that birds evolved from reptiles. However, it is unable to explain the enormous difference between these two classes of living beings. Birds exhibit properties that differ from reptiles: they have a skeletal structure consisting of hollow and extremely light bones, they have a unique respiratory system and are warm-blooded creatures. Another unique difference that creates an unbridgeable gap between birds and reptiles is feathers.

The phrase “light as a feather” describes the perfection of the complex structure of a feather. The design of bird feathers is so complex that evolution simply cannot explain it. Scientist Alan Feduccia says feathers have "a structural complexity that provides mechanical and aerodynamic perfection that has never been achieved by other means."

The design of the feathers gave Darwin pause. Moreover, the ideal aesthetic feathers of a peacock had, in his own words, a depressing effect on him. In a letter to Asa Gray dated April 3, 1860, he wrote: “I well remember the time when the thought of an eye made me tremble, but I have overcome that phase...” Then he continued: “... and now the minute details of this structure make me feel uncomfortable . Seeing the tail feathers of a peacock every time I look at it depresses me!”

Examining the bird's feather under a microscope reveals a stunning design. As you know, there is a rod in the middle of the feather. Hundreds of small barbs emerge from each side of the shaft. The beards of varying softness and size give the bird its aerodynamic nature. Moreover, each barbule has thousands of barbules attached to it, which cannot be seen with the naked eye. These barbs are held together by means of hooks.

The hooks snap together like a zipper. These barbules close together so tightly that even smoke directed at the feather cannot pass through it. If the hooks come off for any reason, the bird can easily restore the feathers to their original shape by shaking itself or straightening the feathers with its beak.

To survive, birds must keep their feathers clean, well groomed, and always ready to fly. They use an oil-secreting gland at the base of their tails to keep their feathers in shape. They use this oil to clean their feathers. This oil also provides waterproof protection when birds swim, dive or fly in the rain.

In addition, in cold weather feathers keep the bird warm, preventing its temperature from dropping. IN hot weather feathers are pressed closer to the body.

Even a superficial acquaintance with such unique system, like a bird’s feather, allows us to conclude the existence of a Creator, Whose infinite intelligence ideally designed and brought into existence the world around us.