The crab probably came to admire the perfect skeletal structure glass sponges View of the Basket of Venus
Sea sponges are primitive organisms. These are invertebrate animals that spend almost their entire lives attached to rocks or the bottom. Sponges are found almost everywhere, from coastal zones to the deepest places in the ocean. Approximately 8,000 species of sponges are represented. They do not have real tissues and organs; their functions are performed by individual cells and layers of cells. Sponges feed by driving water through their own body. The filtrate, where small creatures and various organic particles fall, serves as food for the sponge.
There are also predatory sponges - there are about 140 species. These predators feed on crustaceans and other small animals. Sponges of the family Cladorhizidae use long sticky threads to hunt. cellular structure. When the victim is glued to the thread, it shortens, pulling the victim towards the sponge, which gradually envelops the victim and digests it. Sponges use water filtration not only to obtain food, but also to obtain oxygen for body tissues. According to experts, every day many types of sponges pump through themselves a volume of water that is 20,000 times greater than their own body volume. One of the most unusual species sponges - Cladorhizidae. These creatures can be called living fiber optics.
This sponge belongs to the class of glass sponges (six-beam sponges), which create their base from silicon dioxide. These living organisms are very beautiful, since the threads of the “skeleton” are intertwined in the most unusual combinations. Glass sponges of the phylum Cladorhizidae usually live with shrimp, which occupy the internal cavity of the skeleton. The shrimp swim inside as larvae, and after molting they remain to live inside, since they cannot pass through the cells of the glass net. The size of glass sponges reaches 20-30 centimeters.
Experts from Bell Labs were previously interested in glass sponges. Representatives of the company, having studied the fibers of the skeleton, concluded that the material is similar in structure to optical fiber. The length of the sponge fibers is 5-15 cm, and the diameter is 40-70 microns. The structure of the fibers is complex; they are multilayer objects. The center is a rod made of, in fact, quartz glass. This rod is surrounded by layers of organic matter and shell. Moreover, the shell has a special structure that makes it possible to conduct light through artificial fibers.
Specialists from Bell Labs were surprised by the fact that sponges create their fibers in water at low temperatures. Man produces optical fiber using expensive equipment at high temperatures in special ovens. According to specialist Joanna Eisenberg, sponges can be an example alternative way fiber optic production. Moreover, a feature of the material produced by sponges is its strength and flexibility. Such fibers are much less fragile and practically do not crack. They can be tied into a knot without any problems, and the optical properties of the channel will be practically unaffected. Light passes through such fibers very well, since the sponges use sodium ions when forming their glass skeleton, which improve the optical properties of the material. Naturally, sodium is added by these organisms under conditions of the same low temperature in aquatic environment. For fiber optic manufacturers, monitoring sodium ions in production process still poses a problem.
Bell Labs studied the structure of sponge optical fiber, finding that it consists of several layers. The optical properties of each layer are different. As mentioned above, the center of the sponge fiber is a rod of pure quartz glass. Concentric layers of glass surround the rod as the sponge grows. It is this structure that makes the fiber formed by the sponge very resistant to breaks and cracks. The individual layers are glued together using a special organic glue. As the skeleton forms, the individual fibers intertwine together to form something like a lattice.
The skeletal structure of glass sponges has much in common with the structure of buildings and structures created by humans. True, the “buildings” that the sponge creates are 1000 times smaller than most objects of this type created by man. The photo shows the Swiss Tower from London, Hotel De Las Artes from Barcelona and a structural element of the Eiffel Tower
The lattice is reinforced by a special substance (mesoglea), and the skeleton of the sponge, under the influence of mesoglea and the sheath of fibers, becomes quite strong. According to experts, such a structure is similar to that used by architects who create buildings under seismic conditions. hazardous areas. Such material can be slightly deformed, but it is very difficult to break. Evolving, sponges learned to build the strongest possible skeletons from minimum quantity material. The researchers say the sponge uses just the amount of material needed and no more.
Interestingly, sponges of the species Euplectella aspergillum (the “Venus’s Basket” already mentioned above) are attached to the bottom using elastic glass spicule needles, the diameter of which is 50 microns. Their length can reach 10 centimeters. These spicules are very strong, so it is very difficult to break them by tearing off the sponge.
Last year, scientists studying glass sponges conducted a simulation mechanical properties artificial fibers of these creatures. The goal was to find the optimal sequence of cylinder thicknesses to achieve maximum tensile strength of the skeleton. As it turned out, the calculated parameters are very close to the real ones. Sponges use a decrease in thickness from the center to the edge.
Joanna Eisenberg argues that the glass sponge skeleton is one of the best solutions in mechanical engineering. Perhaps this material can help humans discover new possibilities in materials science and improve engineering design. This structure is very complex, this applies to both individual fibers and the entire skeleton as a whole. “This baffles me. I can’t imagine how sponges form their skeleton from individual fibers, creating almost perfect structures,” Eisenberg said. Scientists now suggest that in the center of each fiber during its formation there is a protein that plays important role in the creation of both the core and the entire optical fiber as a whole.
"It's amazing how many engineering construction techniques use sponges to create the skeleton," says James Weaver, a scientist at the University of California, Santa Barbara.
Basket of Venus, or Euplectella aspergillum- one of the most beautiful sponges. It would be more accurate to say that this sponge has the most beautiful skeleton, presented in the form of a cylindrical openwork plexus of skeletal elements. It is the skeleton of the Basket of Venus that is considered valuable decoration and the dream of many collectors, and thanks to him the sponge received such a romantic name. Its unique skeletal lattice, like a basket, is woven from thin translucent fibers, and could easily touch even the goddess of beauty, love and gardens - Venus.
The first description of this creature was made by the famous English zoologist and paleontologist Sir Richard Owen in 1841, while studying the fauna of the Philippines.
Euplectella aspergillum belongs to the squad Lyssacinosida, part of the class of Six-beam or glass sponges ( Hexactinellida or Hyalospongia). Genus Euplectella currently unites about 15 species of sponges, which popular rumor has dubbed the Baskets of Venus for the beauty and grace of their skeletal structure.
These are typical marine animals, mostly solitary, less often colonial, living in deep-sea places - from 100 m to kilometer depths, preferring, however, to settle at a depth of 400-600 m.
The Basket of Venus can be found in the eastern regions Indian Ocean and in the west Pacific Ocean, mainly in the tropics. The waters around the Philippine archipelago are especially famous for the abundance of glass sponges. More often, Baskets of Venus inhabit deep-sea areas of the shelf zone of continents and islands.
Glass sponges are very ancient animals - the fossilized remains of their skeletons date back to the Silurian period, that is, they are at least 420-440 million years old.
The lifestyle of these animals is poorly understood, since Baskets of Venus are found at considerable depth. Like all sponges, they are sessile animals, attaching themselves to stony or rocky substrates at the bottom. Their food is microorganisms and organic remains found in the water that the sponge passes through the channels of its body.
The Venus Basket sponge has a cylindrical body, the basis of which is a silicon skeleton made of six-rayed needles. The rays of the needles are oriented in three mutually perpendicular planes; there are needles with underdeveloped rays. The silicon skeleton literally looks like glass, so the Basket of Venus, as well as many other representatives of the class of six-rayed sponges, justify the name of their class - glass sponges.
These animals extract silicic acid compounds from sea water and convert them into silica, forming a complex skeletal frame of natural fiberglass. The thickness of the elements of such a frame can be no thicker than a human hair, for this reason the skeletons of glass sponges are very delicate and fragile.
The body height of most species of the Basket of Venus does not exceed 10-20 cm, but can reach more than 30 cm (according to some sources - up to 120 cm). At its top there is a wide mouth, which in adult individuals is closed by an openwork lattice of skeletal formations.
The sponge skeleton is covered with a soft shell, represented by epithelium, mesoglea, in the thickness of which there are other types of cells characteristic of most sponges. It should only be noted that the mesoglea of glass sponges does not contain myocyte cells, characteristic of sponges of other classes. The thickness of the mesoglea between the epithelial cells is penetrated by channels that have chambers along their length, inner surface which are covered with choanocytes - flagellated cells that push water through channels through the body of the sponge.
The unique symbiosis of the Basket of Venus with deep-sea shrimp and some species of crustaceans formed the basis of a beautiful Japanese tradition - to give newlyweds the skeleton of this sponge with a pair of crustaceans that have settled in its internal cavity as a wedding gift.
Small crustaceans enter the cavity through the mouth of the sponge and live there, feeding on organic matter pumped by choanocytes along with water. Inside the Basket of Venus, shrimp and crustaceans feel safe, well-fed and supplied with fresh water, so they do not feel the desire to leave their patron, settling in the cavity of the sponge for a long time. After some time, the shrimp grow up and become prisoners of the skeleton of the Basket of Venus, since they cannot leave it through the openwork lattice of the mouth. However, the shrimp (and there are always a pair of them - a male and a female) are not at all worried about this - they feel great in their “imprisonment”. They reproduce right in their “prison”, and the young shrimp swim away through the mouth of the sponge, most often looking for shelter similar to their “parental home”. 
According to naturalists, shrimp feed in the cavity of the Basket of Venus not only with the “leftovers” of its feast - it turns out that in the darkness of the depths the sponge is capable of emitting light that attracts the smallest microscopic animals to it, which become prey not only for the sponge, but also for its symbiotic tenants. The crustaceans remain to live in the sponge until the end of their days, maintaining marital fidelity to their soulmate. It was this fact that served as the reason for the emergence of the custom described above - to give the newlyweds a Venus Basket with a pair of crustaceans inside as a symbol of marital fidelity.
Apparently, the case of symbiotic relationships presented here should be classified as mutualism, since there is no benefit for the sponge from cohabitation with crustaceans and shrimp, and there is no harm, at least obvious, either.
It is curious that physicists are interested in the skeletons of glass sponges - the properties of the constituent elements of this natural structure ideally correspond to the requirements of the “wires” of fiber optics. Optical fiber production technology is currently associated with high temperatures, which makes it difficult to control the quality and properties of the resulting materials.
Glass sponges produce their “fiber” at a considerable depth, where the temperature does not exceed 2-10 degrees. C. Having adopted the technology of making a skeleton from silica from these animals with low temperatures, physicists would be able to produce better optical fibers and materials.
In addition, the skeletons of glass sponges can help create inexpensive and efficient solar cell elements.
But at present, the skeleton of the Basket of Venus is of greatest value as an amazing souvenir decoration created by nature.
This group includes glass sponges, in which the microsclera are represented by various hexasters. Often the large needles of these sponges, connecting with each other, form a skeleton in the form of a spatial lattice.
Characteristic representatives of the detachment:
basket of Venus(family Euplectellidae), having a cylindrical body, large goblet-shaped
or saccular Ross sponges(family Rossellidae)
And colonial sponges from the family. Euretidae, the body of which is formed by branched and unevenly fused thin-walled tubes.
Some glass sponges have a very beautiful and graceful skeleton. Cleared from organic matter The skeleton of such sponges is used as decoration and souvenirs.
The already mentioned sponge is especially beautiful basket of Venus(Euplectella). Her skeleton looks like a delicate openwork cylinder of such an intricate and delicate structure that it seems to have been made by a skillful human hand. They say that the first copy of this sponge, brought to Europe, was bought for the fabulous sum of 600 marks. And to this day, the basket of Venus is considered a very valuable decoration.
Another glass sponge hyalonema(Hyalonema), has a rounded body sitting at the end of a rod of very long thick needles. The skeleton of this sponge is used as a whole or its individual parts are glued together into fancy artificial decorations.
The fishery for both of these sponges is concentrated mainly off the coast of Japan and the Philippine Islands. The extraction of glass sponges is fraught with great difficulties, since they live at considerable depths and have a very fragile skeleton.
Order Amphidiscophora
The sponges of this order contain microsclera in the form amphidisks, whereas hexasters are completely absent from their skeleton.
A typical representative of the squad is sponge hyalonema(family Hyalonematidae), has a goblet-shaped or oval body sitting on a long bunch of needles, with the help of which the sponge takes root in the ground.
This also includes giant sponge monoraphy(Monorhaphis chuni), having a strongly spongy cylindrical body about 1 m in height, which is pierced in the form of an axis by a needle reaching a length of 3 m with a thickness of 8.5 mm.
>> Sponge "Venus Basket"Sponge "Venus Basket"
The goddess Venus reigns not only among flowering gardens; even the ruler of the ocean Neptune and the inhabitants of his deep-sea kingdom do not dare to resist her power of beauty and perfection. The lace of the best Flemish craftswomen, which by a whim of nature ended up on the seabed, biologists did not hesitate to name after the most beautiful one - in honor of the goddess of love Venus. Euplectella aspergillum or Venus' Basket is an amazing living creature, unanimously recognized as the most beautiful of the sea sponges. Her skeleton has a truly unearthly beauty, simultaneously reminiscent of an elegant vase, a lace scarf, and a bride’s veil. A basket woven by nature from silicon salt fibers, in which you would not be ashamed to present flowers even to Venus herself.
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Sponge "Venus Basket" |
Encyclopedic data. Kingdom - animals, phylum - sponges, class - glass or six-rayed sponges, order - Lyssacinosida, family - Euplectellidae. First to classify and describe mysterious creature famous explorer Flora and Fauna of the Philippines, English zoologist and paleontologist Sir Richard Owen in 1841. Currently, science knows 15 species of sponges, which are united by the name Basket of Venus.
An interesting fact: the first basket of Venus brought to Europe was sold for 600 marks, a fantastic amount at that time even for jewelry.
The Basket of Venus is a sea animal. Its habitat extends mainly to a tropical climate: the western Pacific Ocean and the eastern Indian Ocean. Most sponges, the Venus basket and absolutely all its species, are found in the waters of the Philippine archipelago, namely local residents were the first to find a way to carefully process a sponge and began to use its skeleton as an amulet or decoration. The shelves of islands and continents are a favorite place for sponges to settle. The Basket of Venus is a predominantly solitary animal, with rare exceptions it is colonial. A comfortable depth for sponge life is 400-600 meters; some specimens can be found either a hundred meters from the sea surface or one kilometer.
The Basket of Venus, in addition to its beauty, can also boast of its age. This is the oldest animal, the fossilized remains of which are 400 million years old and belong to the Silurian paleontological period.
It is worth noting that the meaning of the name of the sponge is fully revealed only when its calcareous skeleton becomes visible. A special solution and a gentle digestion process remove the soft tissue, and after this the unique pattern of the internal structure of the sponge is always revealed.
The lifestyle of the basket of Venus is largely unknown, since it is not yet possible to conduct research at a depth of more than 400 meters. A sponge is a sessile animal, that is, attached to the bottom or rocky substrate. Sponge food consists of organic remains and microorganisms.
The sponge skeleton is covered with a soft shell, which includes epithelium and mesoglea. The thickness of the mesoglea between the epithelial cells is penetrated by channels, which have chambers along their length, the inner surface of which is covered with choanocytes - flagellated cells that push water and microorganisms through the channels through the body of the sponge.
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Sponge "Basket of Venus" |
The basket of Venus is a small creature, the average length of a fragile sea vase is 10-12 centimeters, but there are exceptions up to one and a half meters long. The body of the sponge is a cylinder, the base is living geometric figure- this is a skeleton made of silicon, which, in turn, is a connection of six-beam needles. The fragile snow-white creatures are real chemists, they synthesize silicic acid compounds from sea water and then convert them into silica. Silica further serves as a major component in the formation of the natural fiberglass Venus Basket skeleton frame. Each element of the frame is a thin thread, approximately equal in thickness to a human hair, so it is not difficult to guess that the skeleton of a sponge is fragile, delicate, weightless, and airy.
The orientation of the six-rayed spines of the skeleton is interesting, which creates the amazing structures of the sponge skeleton. The needle beams are in a mutually perpendicular position relative to each other. The basket of Venus is often called a glass sponge; the thinnest silicon needles literally look like the work of the best glassblowers, so the name is justified in every letter. Even biologists added to the classification an equivalent synonym for six-rayed ones - glass sponges.
IN Lately Physicists began to become interested in the skeleton of Venus's basket. It turns out that the properties of the sponge skeleton, or rather most of its components, ideally meet the requirements of fiber optics technology; wires created by “nature” are superior in quality to analogues developed by man. What exactly do physicists need from a deep-sea sponge? On at this stage development, the production of optical fiber takes place at high temperatures, which does not allow for maximum effective monitoring of the quality and properties of the final product. The basket of Venus “can” produce fiber at temperatures from 2 to 10 degrees! Consequently, scientists are scratching their heads about how to adopt the technology from animals and successfully produce optical fiber from silica at low temperatures. This would not only simplify and reduce the cost of the manufacturing process, but would also allow humanity to obtain higher quality optical materials and fibers.
And more about the practical use of glass sponges. The Venus basket skeleton can help create inexpensive and productive elements for solar cells.
The basket of Venus is named after the Roman celestial goddess not only for amazing beauty. Don't forget that Venus is the goddess of love. The deep-sea namesake of the goddess does not lag behind her patroness and demonstrates a unique symbiosis for nature with deep-sea shrimp - Spongycola venus - and some species of the smallest crustaceans.
Small crustaceans at the beginning of their life path penetrate into the cavity of the sponge and happily live in it, feeding on organic matter that Venus’s basket pumps through itself along with water. A kind of cornucopia that, in addition, provides safety. The shrimp are in no hurry to leave their cozy home in the cavity of the sponge, but sooner or later you have to pay for any comfort: the shrimp grow, the openwork mouth of the sponge through which they climbed becomes narrow for them, and the satisfied inhabitants turn into no less satisfied, but now prisoners. Surprisingly, the prisoners are always a male and a female; they reproduce in their glass prison and do not experience the discomfort of lifelong imprisonment. Young shrimp are released into freedom the same way their parents got into the sponge - through the mouth. According to natural biologists, a pair of shrimp living in the cavity of Venus’s basket receives food not only from the vital activity of the sponge itself. The skeleton of the sponge in the deep-sea darkness emits a rather bright glow, attracting microscopic animals, which become both prey for both the basket of Venus and the shrimp living in it. The above case of symbiotic relationships should be classified as mutualism, since there is no benefit or benefit for the sponge from the “tenants,” but there is no harm, or at least science has not yet identified any harm.
A pair of shrimp spends their entire life in the cavity of Venus's basket. The Japanese saw this as a symbol of marital fidelity and endless love. Therefore, a long time ago, a tradition arose in the Land of the Rising Sun: to give newlyweds a basket of Venus with a pair of shrimp inside. The souvenir should be kept as long as the marriage lasts. And not only do two small crustaceans help the bonds of love, Venus herself favors those who take care of the talisman that bears her divine name.
Target: study the type of sponge as the first multicellular animals.
Tasks:
- consider the history of the appearance of sponges, their diversity and significance;
- attract students' attention to a little-studied group of animals;
- introduce the variety of sponges.
Equipment: tables on the classification of sponges, presentation “Sponges”. Video fragment: “Regeneration of sponges.”
Basic terms and concepts: multicellularity, cell differentiation, choanocytes, biofilters, regeneration, symbiosis. A systematic approach to developmental training was used.
DURING THE CLASSES
I. Organizational moment
Students' mood for the lesson.
II. Check of knowledge
Instead of dots, choose the appropriate words
Option 1.
- Amoebas move using...
- The food composition of ciliates - slippers mainly includes...
- In freshwater protozoa, metabolic products and excess water are excreted through...
- The reactions of protozoa to stimuli are called...
- Green euglenas... react to light.
- When advancing unfavorable conditions Most protozoa go into a state...
- The disease is caused by malaria when it enters the blood...
Option 2.
III. Teacher's story:
1. The history of the discovery of sponges
How much do we know about sponges? And most textbooks mention sponges somewhat casually, not in great detail and, it seems, not very willingly. What is the matter, why was a whole type of animal, quite numerous and widespread, so unlucky?
Zoologists still don’t know exactly where, in what part of the animal kingdom to place sponges. Either these are colonies of protozoa, that is, unicellular organisms, or primitive, but still multicellular animals. And sponges received the status of animal organisms only in 1825, and before that they, along with some other sessile animals, were classified as zoophytes - half-animals, half-plants.
Calcareous sponges have been known since the Precambrian, glass sponges since the Devonian. Currently, most researchers, following Ivan Mechnikov, consider a hypothetical animal, the phagocytella, as the ancestor of sponges. This is evidenced by the structure of the sponge larvae, which is close to the most archaic animals from the subkingdom of phagocytelliformes - trichoplaxes.
However, Haeckel believed that sponges evolved from collared flagellates, in whose colonies anatomical and functional differences arose.
Sponges turned out to be a blind branch of evolution; no one descended from them.
2. Multicellular animals - sponges
– Guess what features sponges will have in contrast to protozoa? Use paragraph 5 of the textbook, page 22. Write down the features in your notebook.
Teacher's additions:
1. The presence of choanocyte cells or collar cells with flagella, the beating of which creates a flow of water necessary to supply the body with food and oxygen and to remove carbon dioxide and metabolic products. Choanocytes of some complex sponges are capable of “pumping” a volume of water every minute equal to the volume of the sponge itself.
Cross section through the wall of the sponge body 1 – mouth, 2 – body cavity, 3 – channels
2. The body consists mainly of a gelatinous substance, inside of which there is a skeleton of protein, calcium carbonate or silica. Sponges belong to the cellular level of organization
3. Sponges already have cell differentiation, but there is still no or almost no coordination between cells necessary for organizing them into tissues.
4. The cells form a very loose, fragile complex, and if you rub a sponge through a silk sieve, the connections between them can be completely disrupted, although the cells themselves are not damaged. The cells can then unite again into a complex similar to the original one.
5. Since sponges have a number of unique morphological features characteristic only of this type, they are usually considered a side branch of the evolutionary trunk of multicellular animals. They evolved from flagellates independently of other Metazoa and did not give rise to any other phylum.
6. Living sponges resemble a piece of raw liver; They usually have a dirty brown color, a slimy surface and an unpleasant odor.
7. Sponges are sessile organisms of various sizes from 1 cm to 2 m in height; they may form a flat growth, may be spherical, fan-shaped, or have the shape of a bowl or vase.
Three types of sponge body structure: the dark stripe indicates the choanocyte layer
8. Most sponges are hermaphrodites. Reproduction is sexual and asexual. Asexual reproduction occurs by budding, sometimes internally. The buds that form on the body, as a rule, are not separated from the mother’s body, which leads to the appearance of colonies of the most bizarre shape.
9. During the sexual process, a sperm fertilizes an egg; A larva emerges from the egg, floats in the water for some time, and then attaches itself to the bottom.
10. When the larvae transform into adult sessile forms, the germ layers of sponges are distorted: the outer flagellar cells migrate inward, and the cells of the inner layer move outward.
11. Sponges respond slowly and weakly to various irritations, since there are no nerve cells in their body.
12. The receipt of oxygen and the release of dissimilation products occurs through the internal and external surfaces of the body.
13. Digestion, like that of protozoa, is intracellular.
14. Substances decomposed as a result of digestion partially diffuse into other cells and are absorbed there, and are partially assimilated in place.
VI. Did you know?
History of sponge use
1. Toilet sponge in ancient Rome.
The ancient Romans did not know toilet paper; instead they used a simple device - an ordinary Mediterranean sponge on a stick.
A little about the sponge. It is a marine invertebrate animal whose skeleton consists of silica, or silica and spongin, or spongin alone. This skeleton has been used by people since ancient times.
Toilet sponge
When dried, it is hard and brittle, but when wet, the sponge becomes soft and holds water well. In addition, due to the presence of antiseptic substances in tissues, the sponge has bactericidal properties
The “life” of a bath sponge in modern conditions for one owner is a couple of months. Sponges are still a commercial item, and in the markets of almost all Mediterranean countries you can see sponges lying around.
Judging by the testimony of contemporaries, sponges were in common use (it would be strange to imagine a Roman carrying a personal sponge into a public toilet). In the toilet room there was usually a vessel - a bucket or basin, often made of stone, in which there were several sponges. It is suggested that before and after use it should be washed in a small channel of running water, which was usually located in the center of the toilet. In a decent toilet, a attendant looked after the sponges.
Small private toilet in the bath complex of a Roman villa
1) Sponges provide an extremely convenient refuge for other organisms, and whole line small aquatic inhabitants use their pores as homes. Here it is necessary, first of all, to name the larva of the lacewing - Sisyra fuscata, which is 4.5 mm in length, black-brown in color. In addition, sponges provide shelter to some species of caddisflies (Hydropsyche ornatula), chironomids (Glyptotendipes), water mites (Unionicola crassipes), etc. Some species of ciliates and rotifers are permanent commensalists of sponges. Sometimes sponges live in close cohabitation with bryozoans, and these organisms even germinate each other.
2) Sponges are active biofilters; some of them are capable of passing tens and hundreds of liters of water per day through their bodies.
3) It happens that sponges, growing in water bodies, cause some, albeit small, harm.
4) It was observed that they clogged the openings of water pipes and thus disrupted the operation of waterworks.
5) The bottoms of wooden ships can become overgrown with sponges, which impedes their speed of movement.
6) In fish ponds, thistle is considered undesirable. When it develops strongly, it spoils the water, giving it bad smell and taste.
2. Bodyaga sponge is used in medicine.
A person who comes into contact with a sponge may develop severe itching and mild swelling of the fingers, possibly due to the histamine-like effect of the extract from the sponge.
Finally, let's mention the Japanese. They, as always, “ahead of the rest”, started toilet sponge plantations, and those who came up with such a good idea clearly made the right decision. They make good money.
VII. Checking your understanding of the material. Completing the crossword
1. Deep-sea forms of sponges up to 50 cm high. Skeletal spines contain silicon. Body color is white, gray, yellow or brown.
2. Natural, correct location parts of the body relative to the center in multicellular animals.
3. Sponges with a calcareous skeleton, living in the shallow waters of seas and oceans. The color is yellow-gray.
4. The way of life of the animal when it is fixedly attached to the substrate (rock bottom or large object).
5. A sponge used by humans in medicine to treat rheumatism, bruises, and bruises.
6. Sponges with a silicon skeleton. The coloring is varied. They can reach sizes up to 1 meter.
7. Unicellular algae, found in the cytoplasm of sponges and providing it with oxygen.
8. Cells that perform an individual function.
9. Skeletal formations present in the gelatinous substance of the body of sponges.
Internet resources:
Original news:
Literature:
- N. Green, W. Stout, D. Taylor. Biology, vol.1. – M.: Mir, 1996.
- V.A. Dogel. Zoology of invertebrates. – L.: graduate School, 1983.
- V.A. Dogel. Well comparative anatomy invertebrates. – L.: Leningrad University, 1967.
- V. M. Koltun. Animal life, vol. 1, M., 1968
- A.A Yakhontov. Zoology for teachers publishing house "Prosveshchenie". Moscow 1968
- Basics of paleontology. Sponges, archaeocyaths, coelenterates, worms, M., 1962;
This living organism is unique in its age. The Antarctic sponge is the longest-lived of long-livers. It is possible that sponges grow very slowly due to low temperatures. Their metabolism is slow.
Scientists have discovered that the oldest Antarctic sponge is more than one and a half thousand years old. Now imagine for a moment how many interesting things this sponge has seen in its lifetime. It is these living creatures that hold the record for longevity in the animal world.
Sponges for giants and dwarfs. Slide 11
Among the primitive marine animals - sponges - the highest is Neptune's cup.
The “height” of this sedentary, truly goblet-like creature can reach 120 centimeters. But the heaviest sponge was found in the Bahamas. She had a girth of almost two meters and weighed 41 kilograms. True, after it was dried, the weight of the sponge became much smaller - only 5 kg 440 g. Well, even Thumbelina, perhaps, could not wash herself with the smallest sponge: its diameter is only 3 mm.
Neptune cup sponge Swarczewski papyrus 1-4 mm.
The body is cylindrical, up to 30 cm long, and consists of hexagonal needles, which contain silica. Deep-sea view of the tropical Pacific and Indian oceans.
In Japan, Euplectella is associated with the wedding ceremony. When young people get married, they receive a beautiful translucent basket with a pair of dried shrimps inside as a gift. The Japanese have long noticed that in each such sponge there live two shrimp - a male and a female. They get there at the larval stage and, when they grow up, they can no longer leave it. Therefore, the gift has a symbolic meaning for the newlyweds - it serves as the personification of constant love, fidelity and long-term marital happiness. Translated from Japanese, the sponge is called “to live, grow old and die together.”
Basket of Venus
Few zoologists study sponges. This is explained simply - they do not have much practical significance, they are unattractive in appearance, not like, for example, birds, tigers or sea stars. At the same time, the name of one of the largest Russian specialists in sea sponges is known to everyone. Nowadays, few people remember that the great Russian traveler, ethnographer and anthropologist Nikolai Nikolaevich Miklouho-Maclay was a zoologist by training. A student and assistant of the great Ernst Haeckel, he worked a lot on the sponges of our seas. At the end of many scientific names sponges living in northern seas, we meet the name of the author of the species description – Miclucho-Maclay.
Kalymnos. Sponge divers.
Kalymnos is a fairly small island in the Aegean Sea, part of a group of over 50 Dodecanese islands in southern Greece. Although sponge diving has been a source of income for many Greek islands in recent centuries, Kalymnos is known as the center of the Greek sponge industry. The waters around the Greek islands are favorable for their growth due to the high water temperature. The best quality sponges were in the south Mediterranean Sea. It is not known exactly when the sponge came into use. In ancient writings (Plato, Homer) a sponge is mentioned as an object for washing. In Kalymnos, sponge diving also dates back to ancient times. This is one of the oldest professions on the island. Sponge diving brought social and economic development to the island. In the past, diving was done using the skin diving method. The team went out to sea on a small boat. To search for sponges at the bottom, a cylindrical object with a glass bottom was used. As soon as there was a sponge, the diver took it out from the bottom. He usually carried a 15 kg flat stone, known as a "skandalopetra", in order to quickly reach the bottom. The cut sponge was collected in special nets. The depth and time of the dive depended on the size of the diver's lungs. Although it was quite difficult to obtain this way, a lot of sponges were obtained and sold this way. Many merchants on Kalymnos became very rich. Since 1865 there has been a boom in the sponge trade. The reason for this was the introduction of a standard diving suit or Spacesuit as the Greeks called it. A merchant from the island of Symi brought equipment, probably Sibe Gorman. The advantages were obvious. Now, divers could stay as long as they wanted and for great depths. The best sponges were found at a depth of about 70 meters. The diver could now walk along the bottom and look for them.
In 1868 the sponge diver fleet consisted of:
300 ships with divers (from 6 to 15 divers on each ship) 70 ships that caught sponges with harpoons.
With the advent of the suit, trade experienced enormous growth. From Kalymnos, ships left for the Aegean and Mediterranean seas. They went as far as Tunisia, Libya, Egypt, Syria. They were at sea for 6 months.
The profit from the extraction and sale of sponges was high. For divers, there were working conditions in the suit. However, there was great danger during diving – decompression illnesses. Soon after the introduction of the suit, the first accidents with divers occurred. The symptoms, severe pain, paralysis and death were ultimately terrifying for the divers and other crew as they had no idea what was causing it all!
Daily dives to 70 meters or more and ascents without safety stops had a devastating effect: in the first year of use of the suit, about half of the divers were paralyzed or died from decompression sickness. Between 1886 and 1910, about 10,000 divers died and 20,000 were disabled.
It had big influence for all residents of Kalymnos. Each family had fathers, children, brothers and other relatives who were paralyzed or did not return from the season. Towards the end of the 19th century this caused great unrest in Kalymnos, especially among women. At that time the island was occupied by the Turks. The women asked the Turkish Sultan to ban the spacesuit, which he did in 1882. Profits fell, divers returned to the old method of mining (skin diving). After about 4 years, the suit began to be used again and new accidents occurred.
Modern mining sponges
Most wide application from ancient times to the present day, they have toilet sponges, the skeleton of which is devoid of mineral needles. Toilet sponge fishing is carried out in temperate, subtropical and partly tropical seas at shallow depths.
The diver lifts the sponge from a rock or other substrate and places it in a net, which is then lifted with a rope into the boat. Sometimes a dredge or an iron grapple is used, but with this method of extraction many sponges are damaged.
VIII. Advance homework: repeat § 5, find Interesting Facts according to the “Coelenterate” type.
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