Shell amoebas: habitat and structure
Amoeba is a known representative of the simplest organisms. But it turns out that among them there are quite unusual species. Shell amoebas are one of them.
General characteristics of the single kingdom
These organisms are typical representatives of protozoa or unicellular animals. Detachment Shell amoebas belong to the class Kornozhki.
They have the typical features of the simplest. Their body consists of a single cell that performs the functions of the whole organism. Like all amoebas, this species does not have a permanent body shape, since it does not have a compacted surface layer. Amoebas move with the help of prolegs - non-permanent protrusions of the cytoplasm. The organelles of the simplest animals include the nucleus, contractile and digestive vacuoles.
Shell amoebas: habitat
The main medium of these protozoa are fresh and salty reservoirs. But they can also be found in wet soil, silt, mosses.A special feature of marine life is a large number of holes in the shell, through which numerous pseudopods or pseudopods can be seen. Some species prefer to live in highly polluted water.
In the life cycle of the shell amoebas, the state of the cyst begins. This is the adaptation of these animals to changes in environmental conditions. For example, to the drying up of water bodies. During this period, the cell membrane becomes more dense, the intensity of physiological processes decreases markedly. When the situation is normalized, amoebas go to the usual form of existence.
Structure and vital processes of shell amoebas
These unicellulars are very similar to their "namesakes". Like amoeba protei, they do not have a permanent body shape. The organelles of motion are pseudopodia or pseudopods. Such organisms lead an active lifestyle. But the body of shell amoebas is not visible. It is completely hidden in the sink, from the mouth of which the protozoa only release their paws.
The movement of shell amoebas is very interesting. They cling to the support with one paw, pulling up the body with the sink.With the help of movement organelles, food particles are captured. Their digestion occurs by phagocytosis in special vacuoles. Breathing is carried out all over the body. Contractile vacuoles are responsible for the regulation of water-salt metabolism.
Like all protozoa, this type of amoebae multiplies in a primitive way - by dividing the cell into two parts. This process has its own characteristics. The shell begins to form first, and only then the cell is divided. Initially, the maternal and affiliated organisms are anatomically interconnected by a cytoplasmic bridge. Then it disappears, and shell amoebas become independent individuals.
Another method of reproduction is multiple division. This process is carried out inside the sinks. From them go naked amoebas. In the water they divide again. In this case, the shell is formed around the new cell. Among the amoebas are unusual forms. Their sink is soft. Therefore, the division occurs by pereshnurivki in half.
The shell of this amoebae can have a different shape. It can be round, bag-shaped or flat.The chemical composition of the shells is also characterized by diversity. It can be organic or chitin-like.
But most often shells are made up of the main substance. It is allocated by the animal itself. It happens in two stages. First, amoebas draw in solid particles inside the body. These can be fragments of shells of diatoms or sand. Then there is the release of these substances, as a result of which the amoeba shell of this species is formed.
Anatomically, the shell amoeba consists of three parts. At the top of the shell are the nucleus and intermittent cellular structures called inclusions. The middle zone of the body is called vacuolation. Here intensive processes of splitting of organic substances and regulation of osmotic pressure occur. This happens with the help of digestive and contractile vacuoles. In the area of the hole in the sink is the third zone. It is called a protoplast. It is here that the formation of prolegs.
Value in nature and human life
It is hard to believe, but such major sedimentary rocks, like limestone and chalk, are the result of the vital activity of these organisms.The importance of shell amoebas as part of natural ecosystems is great. This is an integral link in the food chain of aquatic biogeocenoses. By the presence of shell amoebas, scientists often determine the degree of contamination of water bodies.
There is a dangerous species among them. Although cases of infection are few, such an amoeba is a human pest. She lives in fresh water. It enters the human body through the nasal cavity, from where it moves along the channel of the olfactory nerve to the brain. The simplest destroys this organ, which leads to headaches, a sharp increase in body temperature, chills, fever, hallucinations. In all cases, this infection was fatal.
So, shell amoebas are representative of the simplest kingdom Sarkodovye. These are inhabitants of fresh and salty reservoirs, where they move with the help of pseudopods. The structure of the shell amoebas is represented by a single cell. It has no permanent form, it is outside covered with a sink. It may consist of organic or mineral matter. The main importance of these organisms in nature is the formation of sedimentary rocks: limestone, chalk and shell rock.