underwater world is so diverse and unique that sometimes difficult to distinguish plants from animals.So bizarre shapes are creatures living there.Large marine giants and very microscopic planktonic crustaceans, colorful and bright, predators and herbivores - a mad variety of living organisms.One of these wonderful creatures and are a sponge, which will be discussed further.
General
characterize the situation of these animals in the organic world, you can:
- Empire - Cell;
- kingdom - Animals;
- subkingdom - Multicellular;
- type - Sponges.
Today we know that there are about 8000 species.300 of them inhabit the seas of our country.
Classification
Type Sponges unites all known representatives of four large classes.
- Calcarea, or lime.Form the exoskeleton in the form of calcium salt deposits.
- Ordinary or Kremnerogovye.Chief Representative - badyaga.
- Glass (six-rayed).The number of classes is low.
- Coral - very poor class types.
All of these sponges have their own characteristics, not only external but also internal structure, way of life and economic importance in human life.
external structure
Perhaps the most unusual in all characteristics of these animals will be just the outer appearance.Features of the external structure of the sponge are defined by a variety of body shapes which they are characterized.Thus, representatives of different classes can be in the form:
- glass;
- bowl;
- tree structure.
symmetry of the body in form of single - bipolar axis, from colonial - mixed.Each individual has a special flat sole with which it is attached to the bottom, or other substrates.Sponges are often immobile lifestyle.
On the top side of the body there is a special hole, which is called "oskulyum."It serves to remove excess water from the internal cavity.Outside, the body covered with a layer of cells - pinakodermoy.They resemble in their structure epithelial tissue of higher animals.
However, there are also distinctive features - the presence of wide pores.The structure of the sponge provides the absorption of food particles through the top opening is not, namely through numerous penetrating body punching that can contract and expand.
Under the outer layer are arranged two to consider in more detail later.The color scheme of both single and colonial forms is quite diverse.There are the following types of stains:
- gray;
- green;
- purple;
- yellow;
- white;
- red;
- brown;
- mixed.
Type Sponges very animates the underwater world, making it even more vivid, colorful and attractive.Moreover, if considered separately taken individual on the land surface, it will have a very unattractive form resembling raw liver brownish slippery ball, publishing is not entirely pleasant aroma.
internal structure of Representatives
types of sponges similar structure, whether it be a single individual or attached to the colony.Just below the outer layer of porous dermal cells is a special intercellular substance, forming a shell enough volume.It loosely arranged cells, and their form is different.The fabric is a bit like the fat in the higher ground of Representatives.This structure is called "mezohil."
Under this layer is the inner cavity, lined with a number of special cells.It gastric layer.All food it gets here, and here comes the digestion.All wastes, along with excess water are sent to the upper opening of the body and excreted through it out.
sponge structure also necessarily involves a kind of skeleton.He formed of lime, phosphorus, organic salts, which are produced in special cells mezohila.It not only gives the lips a certain body shape, but also has implications for safety from mechanical damage to the internal cavity.
characteristic sponge-like would be incomplete if you do not indicate the main feature of these animals - their body does not have a tissue, but only includes different in shape and structure of cells forming layers.It is considered the main difference from all other animals.
Aquifer System is also interesting individuals.Different classes it can be unequal.In total there are three basic types of it:
- Ascon - all communication with the external environment through a system of tubes through which water moves in a special cell chambers.The most simplified Aquifer System, which is found in a few representatives.
- Seacon.A more advanced system, which includes a network of branching tubules and ducts running into the special cell chambers with flagella.
- Leykon - oskulyumov a network, this type of aquifer system is characteristic only of colonial forms.The most sophisticated version of the background of all the previous ones.
reproduction in sponges occurs both sexually and asexually.Germ cells are formed in the layer mezohila.Then the products come out through the pores of the body and a current flows into the other sponge body, where fertilization takes place.As a result, the zygote is formed, giving rise to the larva.Fry may have different names: amfiblastuly, parenhimuly, tselloblastuly.
Speaking of asexual reproduction, then it is based on a process of budding, ie disconnection of the body followed by regeneration of the missing structures.Most of the type of sponges includes hermaphroditic animals.
Features lifestyle
If we consider the diversity of multicellular animals of the world, should be referred to the most primitive sponges on the organization stage.However, it is also the most ancient animals, there will be many thousands of years ago.During the evolution of their organization has changed little, they retain their characteristics over time.The form of life of Representatives has two manifestations:
- single;
- colonial.
most commonly found massive accumulations sponges among the coral reefs.There are both freshwater species (they are a minority), and the inhabitants of the seas and oceans (for the vast number of species group).
Type Sponges includes animals that feed on small organisms or their remains.In the structure of their body cells have special for collar with flagella.They just grab drifting food particles, directing them into the inner paragastralnuyu body cavity.Digestion is carried out inside the cells.
By way of foraging sponges can be called passive hunters.They sit lazily on the attached site in anticipation of sailing nutrient particles.And only when they are already very close, capture them through the pores and is sent along with the flow of water inside the body.
Some species are able to move, even though it still has a sole for attachment to the substrate.However, their speed is so small that for the whole day special unlikely to advance further than a meter.
Variety sponges
For such primitive animal diversity of the quite impressive - in fact there are about 8000 species!And according to some recent data, this figure is already approaching to 9 thousand.External diversity due to differences in body shape, color and type of skeleton body color individuals (or colonies).
Class Glass sponges
Very interesting in its variety of external glass sponges.They are not so numerous as the other, but have an unusual skeleton.This is one of the largest species, which includes the type of cloth.General characteristics of the representatives of this class can be expressed in a few paragraphs.
- Latin name of the class - Hexactinellida.
- The skeleton is formed of silicon compounds is therefore very strong.
- type needle bearing body, which is dominated by six-pointed structure.
- larvae species parenhimuly or tseloblastuly.
- aquifers type leykona.Most colonial
- than single form.
- sometimes up to 50 cm in height.
most common representatives are such as:
- hialonema Siebold;
- euplektella.
class of ordinary or Kremnerogovye, sponges
type sponges, representatives of photos which you can see in this article also includes the most numerous class of the number of individuals - Kremnerogovye or Ordinary.The name received for features in the structure of the skeleton - it consists of silica and spongina.By gentle enough hardness and is easily destroyed.Form needles skeleton is very diverse:
- asterisk;
- anchor;
- mace;
- sharp needles and so forth.
most common freshwater representative of a fresh-water sponge - sponge used as an indicator of the purity of the water body.Externally unattractive brown color of brown, sometimes dirty yellow.Used by man for different needs.
What other representatives found among ordinary sponges?
- Miksily.
- Marine loaf.
- Baikal sponge.
- Marine brushes.
- hondrokladiya Giant and others.
Class calcareous sponge
It includes representatives having strong and beautiful limestone skeleton.They live only in the seas and oceans.Painting pale or absent.Needles skeleton may have about three beams.Key representatives: Ascona, Seacon, leukandry.
Class Coral sponge
most a few representatives that resemble coral branches.This occurs due to the formation of a powerful calcareous skeleton of different colors and patterned structure.
Representatives geratoporella Nicholson, Merlot.Total described only six species of these animals.For a long time they did not differ from the system of coral reefs, so they were opened recently.
use sponges person
important and economic value of individuals belonging to the type of cloth.Representatives used the following needs:
- is a party to the food chain, because they themselves serve as food for many animals.
- used by people for making beautiful jewelry for the body and interior of the house.
- contain substances that can use them for medical purposes (sponge absorbing bodyaga has bruises and wound-healing effect).
- used to create a hygienic sponges - Natural natural products for the cosmetics industry.
- used in engineering and other purposes.
