Animals, like all organisms, are at different levels of organization. One of them is cellular, and its typical representatives are the amoeba proteus. The features of its structure and life will be considered in more detail below.
Subkingdom Unicellular
Despite the fact that this systematic group unites the most primitive animals, its species diversity already reaches 70 species. On the one hand, these are indeed the most simply arranged representatives of the animal world. On the other hand, these are simply unique structures. Just imagine: one, sometimes microscopic, cell is capable of carrying out all vital processes: respiration, movement, reproduction. Amoeba Proteus (the photo shows its image under a light microscope) is a typical representative of the Protozoa subkingdom. Its dimensions barely reach 20 microns.
Amoeba proteus: a class of protozoa
The very specific name of this animal testifies to the level of its organization, since proteus means "simple". But is this animal so primitive? Amoeba Proteus isa representative of a class of organisms that move with the help of non-permanent outgrowths of the cytoplasm. Colorless blood cells that form human immunity also move in a similar way. They are called leukocytes. Their characteristic movement is called amoeboid.
In what environment does the amoeba Proteus live
This simple organism prefers to live in fresh and s alt water. Waterlogging conditions are especially favorable for it, since the process of decay implies the presence of a large number of bacteria that these simple organisms feed on. However, its dysentery appearance feels comfortable in the human intestinal lumen. At first glance, it may seem that this is a parasitic species. But this opinion would be wrong. Being in the intestines, it feeds on a variety of bacteria and does not bring any harm to a person. But if the intestines are affected, the amoeba enters the blood vessels and begins to feed on red blood cells. In this case, ulcers form on the walls. You can get infected with dysenteric amoeba by drinking raw water, dirty vegetables and fruits.
The amoeba Proteus living in polluted water bodies does no harm to anyone. This habitat is the most suitable, since the protozoan plays an important role in the food chain.
Building features
Amoeba Proteus is a representative of the class, or rather the sub-kingdom of Unicellular. Its size barely reaches 0.05 mm. With the naked eye, it can be seen in the form of barelynoticeable jelly-like lump. But all the main organelles of the cell will be visible only under a light microscope at high magnification.
The surface apparatus of the amoeba Proteus cell is represented by a cell membrane, which has excellent elasticity. Inside is a semi-liquid content - the cytoplasm. She moves all the time, causing the formation of pseudopods. Amoeba is a eukaryotic animal. This means that her genetic material is contained in the nucleus.
Movement of protozoa
How does the amoeba Proteus move? This occurs with the help of non-permanent outgrowths of the cytoplasm. She moves, forming a protrusion. And then the cytoplasm smoothly flows into the cell. The pseudopods retract and form elsewhere. For this reason, the amoeba proteus does not have a permanent body shape.
Food
Amoeba proteus is capable of phago- and pinocytosis. These are the processes of absorption by the cell of solid particles and liquids, respectively. It feeds on microscopic algae, bacteria and similar protozoa. Amoeba proteus (the photo below shows the process of capturing food) surrounds them with its pseudopods. Next, the food is inside the cell. A digestive vacuole begins to form around it. Thanks to digestive enzymes, particles are broken down, absorbed by the body, and undigested residues are removed through the membrane. By phagocytosis, blood leukocytes destroy pathogenic particles that penetrate the human and animal body every moment. If these cells did not protectthus organisms, life would be virtually impossible.
In addition to specialized food organelles, inclusions can also be found in the cytoplasm. These are non-permanent cellular structures. They accumulate in the cytoplasm when there are necessary conditions for this. And they are spent when there is a vital need for it. These are grains of starch and droplets of lipids.
Breathing
Amoeba Proteus, like all unicellular organisms, does not have specialized organelles for the respiration process. It uses oxygen dissolved in water or other liquid, when it comes to amoebas that live in other organisms. Gas exchange occurs through the surface apparatus of the amoeba. The cell membrane is permeable to oxygen and carbon dioxide.
Reproduction
Asexual reproduction is typical for the amoeba. Namely, cell division in two. This process is carried out only in the warm season. It takes place in several stages. First, the nucleus is divided. It is stretched, separated by constriction. As a result, two identical nuclei are formed from one nucleus. The cytoplasm between them is torn apart. Its sections separate around the nuclei, forming two new cells. The contractile vacuole is in one of them, and in the other its formation occurs anew. Division occurs by mitosis, so the daughter cells are an exact copy of the parent. The process of amoeba reproduction occurs quite intensively: several times a day. So the lifespan of each individual is quite short.
Pressure regulation
Most amoebas live in the aquatic environment. A certain amount of s alts is dissolved in it. Much less of this substance in the cytoplasm of the simplest. Therefore, water must flow from the area with a higher concentration of the substance to the opposite one. These are the laws of physics. In this case, the body of the amoeba would have to burst from an excess of moisture. But this does not happen due to the action of specialized contractile vacuoles. They remove excess water with s alts dissolved in it. At the same time, they provide homeostasis - maintaining the constancy of the internal environment of the body.
What is a cyst
Amoeba proteus, like other protozoa, has adapted in a special way to the experience of adverse conditions. Her cell stops eating, the intensity of all vital processes decreases, the metabolism stops. The amoeba stops dividing. It is covered with a dense shell and in this form endures an unfavorable period of any duration. This happens periodically every autumn, and with the onset of heat, a unicellular organism begins to intensively breathe, feed and multiply. The same can happen in the warm season with the onset of drought. The formation of cysts has another meaning. It lies in the fact that in this state, the amoeba carries the wind over considerable distances, settling this biological species.
Irritability
Of course, about the nervous system in these protozoaunicellular speech does not go, because their body consists of only one cell. However, this property of all living organisms in the amoeba Proteus manifests itself in the form of taxis. This term means a response to the action of stimuli of various kinds. They may be positive. For example, an amoeba clearly moves towards food objects. This phenomenon, in fact, can be compared with the reflexes of animals. Examples of negative taxis are the movement of the amoeba Proteus from bright light, from an area of high salinity, or from mechanical stimuli. This ability is primarily defensive.
So, the amoeba proteus is a typical representative of the sub-kingdom Protozoa or Unicellular. This group of animals is the most primitively arranged. Their body consists of one cell, but it is able to perform the functions of the whole organism: breathe, eat, multiply, move, respond to irritations and adverse environmental conditions. Amoeba proteus is part of the ecosystems of fresh and s alt water bodies, but is able to live in other organisms. In nature, it is a participant in the cycle of substances and the most important link in the food chain, being the basis of plankton in many water bodies.
