Bird feather under a microscope. The clasp is a zipper on bird feathers. Black plumage of birds

Since childhood, a person's attention has been attracted by winged creatures soaring in the sky - gulls, pigeons, tits, magpies. Tiny sparrows jump amusingly through the puddles. Everyone is familiar with this picture. And now, at an older age, someone, not forgetting about childhood joy, chooses the profession of an ornithologist or zoologist. In the article we will tell and show a photo of what a bird's feather looks like under microscope- this spectacular sight is no less interesting than increasing the fur of animals. And most importantly, it will not be difficult to obtain biological material for research. But first, a little theory, so that your observations are supported by knowledge and facts.

bird feather- this is a formation consisting of cutaneous horny substance and having the most important functional significance in mechanical movement and protection from external natural factors. Between the bare areas of thin boneless skin, pterylia are systematically located - feathers grow from these small depressions.

The plumage allows you to fly, increases the carrying capacity of the wing and its scope, makes the shape of the body streamlined. Without him big birds couldn't take to the air. Another important function is thermoregulation. With the onset of adverse weather, frost, winter cold - the heat is maximally stored inside the body. And in the summer heat, on the contrary, it gives off abundantly. By the way, some types of ancient dinosaurs were also feathered, but unlike birds (considered their only surviving descendants), the cover looked like a small hairy fluff.

In the course of evolution, it gradually turned into real feathers, which (this has been proven) were already, for example, in the bright representative of the Lower Cretaceous era, Sinornithosaurus.

Structure bird feather:

• Barrel or central rod. This is a kind of axis of symmetry, a feather base. It ends with a feather bag deepened into the epithelium;
• Fan (outer and inner plates). They represent a network of connected numerous barbs ending in hooks (they serve to clutch with neighboring ones);
• The bare part of the feather stem is called the chin. This is a semi-transparent horn tube hollow from the inside.

To see the bird's feather under the microscope care must be taken to select the right equipment. It is desirable that your model has two illuminators - the lower illumination will allow you to examine the smallest details of the feather structure “through the light”. And the top one will provide a wide coverage of a large area of ​​the sample in its natural state at low magnification. color scheme. The presence of a video eyepiece will make it possible to take photographs. To install it, the usual eyepiece must be pulled out of the eyepiece tube, and a camera should be inserted in its place (their landing diameter is the same and is 23.2 mm.). The rendered image falls on the touch matrix and is transmitted to the computer via the USB channel. And already in the program window, by pressing interactive buttons, photos and videos are taken.

The finished micropreparation is included in the set "Micromed - Botany and Zoology -14".

To prepare a similar microsample on your own at home, you need to use a slide and cover slip - place a piece of biomaterial between them, smooth it with a dissecting needle or tweezers, drop a drop of colorless fir resin and press the glass surfaces tightly.

Primary focusing is carried out at a low magnification, then, when the image becomes clear, you can change lenses to more powerful ones.

The scientific approach is becoming inextricably linked with modern research technology and magnifying optical instruments. We recommend school light microscopes for viewing pens: Evrika 40x-400x, Levenhuk Rainbow 50L, Bresser Junior 40x-1024x.

The coloring of bird feathers, butterfly wings and some other natural "decorations" is not always due to the presence of specific pigments. Mother-of-pearl, blue, green and some other colors are often given to birds and lepidoptera by the structure of tissues, which sets the ranges of absorption and reflection of visible light.

The structure of the feather also explains the deep black color of the plume of some birds of paradise, found out the authors of an article published in Nature Communications. The black birds that we see in Russian cities - crows and jackdaws - are not so black: they cast either gray or blue. But the plumage of some species of birds of paradise nesting in New Zealand ( Astrapia stephaniae, Seleucidis melanoleucus, Ptiloris paradiseu, Parotia wahnesi and Lophorina superba) are close in blackness to Vantablack artificial paint: they absorb from 99.96 to 99.95% of visible light. In comparison, Vantablack absorbs 99.965% of visible light.

The low reflectivity of the feathers makes these birds seem to be flat: it looks especially strange when the male L. superba performs a mating dance in front of the female. As you can see in the photo, at some moments of this dance, the male turns into a completely flat black figure with an azure pattern:

Very black birds of paradise

Scientists examined the feathers of very black birds of paradise under a scanning electron microscope and modeled their structure using computed tomography, and also traced the trajectory of the beam incident on the feather.

The contour feathers of most birds consist of a rod covered with barbs, to which barbs are attached, covered with hooks that serve to hook the barbs and fix the shape of the feather. In black birds of paradise, the geometry of the hooks is such that it gives additional scattering of light, and, as a result, more complete absorption.

Dakota E. McCoy et al. Nature Communications, 2018 On the left is the feather structure of a paradise crow (Lycocorax pyrrhopterus), no more black than a common crow. On the right is the feather of Wanes' parotia (Parotia wahnesi), a very black bird of paradise.

Researchers believe that the blackness of feathers developed in birds of paradise due to sexual selection; against the background of velvety deep black, the bright elements of their plumage look more advantageous and give an advantage to males with the most black feathers during mating rituals, which in birds of paradise always include a demonstration of the parade plume.

“The feathers of black birds of paradise are very hard and strong, and made of very cheap material. If we manage to describe the structure of feathers so that we can print something similar on a 3D printer, I'm sure we could find a use for such a material, ”Jack Dumbacher, an ornithologist from the California Academy of Sciences, tells Wired in an interview.

American scientists, intrigued by the deep black coloration 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 caused by pigments - melanins - as is usually the case in birds. It's all about the structure of the feather beards, at the ends of which there is a "fringe" of nanogrowths. Such a structure perfectly absorbs light - up to 99.95% of the visible spectrum, which leads to a very saturated black color. In terms of absorption, the feathers of birds of paradise are close to Vantablack - the blackest known material.

In wildlife, color can be formed in two ways - pigment 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. Details about structural coloring are described in the article by T. Romanovskaya. A particular variant of structural coloration 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 correctly ordered fibers of the upper layer of keratin, iridescence occurs (a variant of structural coloration). Iridescence is expressed in iridescent overflows and / or metallic sheen.

"Elements" is already about the unusual behavior of the males of the wonderful bird of paradise. When caring for a female, the male folds its wings and spreads its feathers so that it ceases to look like a bird at all (Fig. 1, g)! Experienced observers noticed another feature of this and a number of other species of birds of paradise (the Paradisaeidae family). 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 United States 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 of them are shown in Fig. 1) - six species of birds of paradise and one species - melampitta - from a close family (Melampittidae). In melampitta and the crow of paradise, the black color is 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" plumage batches. Typically, they are used in mating demonstrations. In some species, for example, the wonderful bird of paradise, along with super black feathers, there are ordinary melanin black feathers. They are located on the back and the male does not specifically show them to the female during mating. Scientists have studied not only the super-black feathers of this species, but also ordinary ones taken from the back.

First, the feathers were studied using a spectrophotometer and a DH-2000-BAL deuterium-halogen light source from Ocean Optics. This source, thanks to deuterium and halogen lamps, as well as special filters, can, in particular, give output light of a given intensity, which includes equally the entire visible spectrum is represented. This makes it possible to avoid distortions in the spectra of the studied samples, since they are illuminated by a balanced light beam.

Spectrophotometry showed that the super black plumage reflects only 0.05–0.31% of light (that is, it absorbs up to 99.95% of the visible spectrum). And ordinary black feathers (paradise crow, melampitta, and those that were taken from the back of a 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 super black bird of paradise feathers approaches that of artificial materials with a very high degree of absorption. So, the blackest material 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 it is repeatedly reflected from the walls of the nanotubes.

In addition to the feathers of birds of paradise, the wings of some butterflies absorb light well. By absorbing up to 98-99% of visible light, they also look very black. This is due to the special microstructure of the scales. (Recall that the wings of butterflies are covered with small scales overlapping one another like tiles.) Super black scales of a male butterfly Troides aeacus from the family of sailboats (Papilionidae, Fig. a) consist of an upper antiglare part and a thin film underneath. The upper part consists of evenly distributed Λ-shaped ridges. The ridges are interconnected by jumpers - veins. As a result, a grating with elongated holes with dimensions of about 490 × 380 nm (and a diagonal of about 620 nm, Fig. c-e) is formed.

Since the wavelength of visible light falls in the range of 380-780 nm, the dimensions of the holes allow most of the visible light to enter them. Photons of light "enter" the holes and are repeatedly reflected from them. Light with a longer wavelength is reflected mainly from the ridges, since it cannot pass into the holes. Repeated reflection leads to the absorption of light - the same as in the case of Vantablack.

To understand the unusual features of the black plumage of birds of paradise, scientists used a raster electron microscope. As you know, bird feathers consist of a rod, from which first-order barbs extend, from which, in turn, second-order barbs extend (see Rod, barbs and hooks). Barbs of the first and second orders are located more or less in the same plane, forming a fan of the feather.

It turned out that the super-black feathers of birds of paradise have a special structure of second-order beards. First of all, the tips of the barbs of the second order 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 pen shaft and barbs of the first order are located. As a result, they form a dense (due to microprotrusions) layer, turned by about 30° towards the feather tip.

The layer of tiny nanogrowths is responsible for the absorption of light. The fact is that the cross section of microoutgrowths is less than the wavelength of light. This allows light to enter the pen. Thus, some of the light that hits the pen is absorbed, and some gets in, but almost nothing is reflected out. Inside the pen, photons of light are again reflected, and some of them are again absorbed. Due to the large number of microoutgrowths, multiple reflections occur, and each time some part of the light is absorbed. This results in the feather absorbing most of the light. In general, the principle of absorption is the same as that of Vantablack.

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

It is interesting that in birds of paradise, like in butterflies, super-black areas often coexist with spots of very bright colors, as if shading them. Based on this observation, the scientists hypothesized that the super black color arose to emphasize the bright parts of the plumage. And those, in turn, can play a role in marital behavior. So far, however, this is only a hypothesis.

Ludmila Maksimova
How are bird feathers arranged? Synopsis of experimental and experimental activities with children of senior preschool age

Integration of educational areas

Cognition:

Establish a link between feather structure and lifestyle

Introduce the structure of the fly and down feather

To form an idea of ​​the detrimental effect on waterfowl birds pollution of water bodies, rivers, seas with oil

art word:

Develop children's creative imagination see characteristic features of objects, compare them.

Health + physical culture:

Encourage the development of fine and gross motor skills

Prevent fatigue in children.

Communication + socialization:

Expand emotional sphere children.

Develop the ability to interact with adults and children

Cultivate goodwill, a sense of compassion for birds who got into trouble.

Develop independence.

Safety:

Observe the basics of security when organizing experiments.

Methods and techniques:

Socio-game situations

art word

Productive activity

Experiences

preliminary work:

Games "Describe bird»

Examining the illustrations

Drawing birds

modeling birds

Organization of developing environments:

1. Box for laboratory research

2. Flight feathers, downy, wings

4. Scales, lightning

5. Feather, wing, flight schemes birds, tails

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

7. Magnifiers, 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 make a riddle

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

It fell into the water and became dry

Children guess - pen.

I open it, I show it. Yes, it's a pen.

Whose pen 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 to Professor Znayka. (symbol Owl) and explore how arranged pen.

The children are seated at the tables.

What is the difference birds from animals? Of people?

They know how to fly.

I put the plumage scheme on the board birds.

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

And due to what they fly birds?

They have wings (schemes of wings, flight)

Display of wings from different birds.

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

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

Looking for differences (color, differences)

Find the longest feather.

This pen is called "flywheel". These feathers located along the edges of the wings.

We are considering.

Feel the pen. What is it? (dense, hard, large)

Exploring with fingers.

I wonder if it's light or heavy?

Children put a pen on their hand, a stone on the other.

Conclude - easy.

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

We draw a conclusion.

Throw up your pen. What do you see?

Falls slowly, gently spinning.

And what makes it easy? The rod is empty.

Cut off the edge of the pen - we see the void (you can try to insert a colored wire, check the emptiness.)

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

When bird flapping wings, the feather elastically springs, without disengaging the hairs.

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

You see, there are protrusions and hooks on the grooves of the feather, which are firmly and easily connected, fastening the surface of the feather, and if they disengage, then the bird connects them with its beak.

(pen outline,)

Experience with lightning.

We fix that this is a pen "flywheel"

And what you still have feathers?

Downy (small, fluffy, thin, the hairs are not linked, the rod is thin).

Superimpose and compare with flywheel (we drive along the hand - soft, fluffy)

Why such a pen bird?

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

I wonder which pen is lighter - feather or fly?

We blow - which one will fly away faster - downy or flyweight?

We find downy feathers on wings.

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

Tail plans.

So why bird feathers?

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

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

Let's do an experiment.

You have a paper pen, apply grease to it with a brush (vegetable oil, and now pipette water. Water rolls down, like this bird feathers no wonder the proverb says "Like water off a duck's back".

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

They may die (picture)

Because birds caught in an oil slick pollute themselves feathers. They stick together, lose their ability to repel air. And birds are dying.

We're doing an experiment.

Pouring oil into a container of water (vegetable oil dyed black, drop pen)

The pen became heavy, the hairs stuck together.

Nature must be protected birds didn't get into that situation.

And where in everyday life can we use a pen?

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

Can be dyed feathers for crafts(color display feathers) .

They decorate hats, clothes.

Downy pillow stuffed with feathers, clothes, jackets (light, warm).

Can you draw? Let's try.

Outlining the silhouette birds in flight(gouache).

What did we learn today in Professor Znaika's laboratory?

How arranged bird feathers and their purpose.

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

O we know a lot about birds,

And at the same time, little

And everyone needs: both you and us,

To have more of them.

For this we save

Your feathered friends

Otherwise, we will reduce to zero

Our winged singers,

Eat trees and fruits

Insect larvae.

And all the gardens will thin out

Without our familiar birds.

To the question how is the pen arranged? given by the author User deleted the best answer is The theory of evolution, which claims that birds evolved from reptiles, cannot explain the vast differences between these two classes of living beings. Birds, by their skeleton, consisting of hollow and weightless bones, by their lung system, by their warm-blooded metabolism, and other similar features, are very different from reptiles. And another property that creates an insurmountable abyss between birds and reptiles is feathers, which are peculiar only to birds.
Feathers, which are based on protein, 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 in the lower layer of the skin tissue and die, moving away from sources of nutrition and oxygen and making room for young cells.
Bird feathers are so complexly conceived that it cannot be explained by the evolutionary process. Renowned ornithologist Alan Feduccia remarks: "Everything distinctive features pen are that it has aerodynamic properties. Feathers are light, have the power of lifting and easily return to their previous shape. "And to the failures of the theory of evolution, Feduccia reacts as follows: "I cannot understand how such an organ, which was originally conceived and planned for flight, could appear originally for other purposes" .
This device of the pen made Darwin think too. In his own words, the extraordinary beauty of peacock feathers gave him a headache. In a letter to his friend Asa Gray dated April 3, 1869, Darwin writes the following:
"I cooled off own theory, because all the time I think about the eyes on peacock feathers. Over time, I came to terms with this problem. At the present time, I am greatly concerned about some devices in nature, the existence of which we did not notice before. For example, I am confused when I see a peacock feather.
FEATHERS AND HOOKS
If you look at a bird's feather under a microscope, it becomes clear how unusually it is conceived and executed. In the middle is the well-known long and hard tube. And on both sides of this tube are hundreds of small feathers. It is the varying degrees of softness and the diverse 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 villi, 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 the crane feather. In one feather there are 650 thin feathers on both sides of the tube, and on each of these feathers 600 fluffs are randomly arranged. All these fluffs are connected to each other with 390 hooks. And the hooks are fastened on both sides, like in a zipper. The fluffs are so tightly pressed against each other by these hooks that they do not even let air through. If the hooks are somehow separated from each other, then the bird needs only to shake itself or, in the worst case, clean the feathers with its beak to return them to their previous state.
In addition, birds, fluffing feathers, do not allow the body temperature to drop. In hot weather, the feathers, tightly pressed to the body, do not let the heat through.