Shell amoeba, the structure of which we will consider in our article, have a number of features that significantly distinguish them from other representatives of unicellular animals. What is special about these amazing organisms?
Shell amoeba: distinctive features
Let's start with the classification of these animals. They are representatives of the Unicellular kingdom, belonging to the Sarcode group. Their body has an unstable shape, as it lacks a densified parietal layer. These cells move with the help of pseudopods - temporary protrusions of the cytoplasm. The cell has a typical amoeba structure. It consists of a membrane, cytoplasm and organelles: nucleus, mitochondria, contractile and digestive vacuoles.
Features of the amoeba shell
Most of the body of amoeba of this species is in the sink. This structure is from 50 to 150 microns in size, has a rounded or pear-shaped shape. Through the opening, which is called the mouth, conch amoeba release pseudopods. This is necessary for their movement. Shells can be formed by pseudo-chitin or organic matter.
In some, they are composed of a substance that is in the environment. The process of forming such shells occurs in several stages. First, the amoeba, using pseudopods, begins to draw in grains of sand, fragments of the shells of diatoms, or other solid particles into the cell. Then they stick together with the help of the cytoplasm and stand out. Anatomically, the cell of the shell amoeba can be divided into three parts. At the top in its cytoplasm are the nucleus and various types of inclusions - reserve nutrients. In the middle are digestive and contractile vacuoles. And closer to the mouth, the cytoplasm is devoid of both organelles and inclusions. Pseudopods form from it.
The relationship of structure and habitat
Shell amoeba are widespread in fresh and salt ponds, silt, well-moistened areas of soil, plant surfaces, and marsh mosses. Their habitat affects certain features of the structure. For example, conch amoeba difflugy, which is a typical resident of freshwater bodies, has one mouth. In the few inhabitants of the seas, the shell is pierced through with calcareous needles, so the pseudopods come out of a large number of holes.
Interesting research
Among the freshwater inhabitants there are a number of amoebas that prefer to live only in heavily polluted water. Other species die under such conditions. This is also proved by numerous laboratory experiments. Imagine that several species of conch amoeba were placed in moist soil at once. Further, this environment is artificially polluted with oil. After a few days, species diversity will begin to decline significantly. Some conch amoeba begin to blacken and change shape.
Amoeba physiology
Shell amoeba are characterized by a number of features of the physiological processes. The reproduction of their cells is carried out by dividing in two, like other representatives of the kingdom. However, due to the presence of a shell, there are a number of differences. So, first a new shell begins to form around the protruding part of the amoeba, and only then division takes place. At first, daughter organisms still remain interconnected by the cytoplasmic bridge. Then it is laced up. As a result, daughter individuals separate and pass to independent existence.
For some species, the method of cell multiplication is multiple division. In this case, the crushing process occurs inside the sink. As a result, naked cells appear outward. They form a shell independently in the process of their life.
Amoeba move with the help of pseudopods. These inconsistent protrusions of the cytoplasm are also called pseudopodia. To move, the amoeba stretches forward the pseudopod, which is held by the support, and then pulls the whole body towards it. In nature, this type of movement is also characteristic of blood leukocytes and phagocytic cells, therefore it is called "amoeboid."
Amoeba are fed by capturing its particles with pseudopodia and subsequent digestion in specialized vacuoles. Gas exchange occurs through the surface apparatus of the cell. The regulation of osmotic pressure is carried out by contractile vacuoles, with the help of which excess water with salts dissolved in it is removed.
With the onset of adverse conditions, shell amoeba fall into a cystic state. Their shell thickens, and the intensity of metabolic processes is significantly reduced. When changing the conditions of existence, the cells switch to normal functioning.
Shell amoeba: significance in nature
These are important organisms in the ecosystem. Shell amoeba, in conjunction with other unicellular organisms, are an integral part of it. These organisms are a link in the food chain, an indicator of the degree of purity of a fresh water reservoir. The value of shell amoebas in the formation of rocks is invaluable. Freshwater and marine protozoa as a result of their life created limestone, chalk and other sedimentary rocks.
In nature, the species of sarcodes is also known, which is very dangerous for humans. The killer amoeba literally feeds on the human brain. At the moment, 23 cases of human infection with this organism have been recorded. This type of unicellular is an inhabitant of fresh water bodies. Inside a person, he penetrates through the nasal cavity, continuing his path in the canal of the olfactory nerve to the brain. As he moves, he destroys all the tissues that serve as his barrier. At the same time, a person experiences severe headaches, chills caused by fever. Then signs of brain damage such as fever and hallucinations begin, which inevitably leads to death.
So, representatives of the Shell amoeba order are unicellular animals belonging to the Sarcode class. Their cells have an unstable body shape and pseudopods as movement organelles. Outside the membrane, this type of amoeba independently forms a shell.