The variety of the simplest: habitats and structural features
In our article we will get acquainted with the structure and variety of the simplest. Representatives of this animal kingdom include more than 70 thousand species. And this figure is not final.
General characteristics of unicellular
The variety of the simplest (7th grade studies this topic in the course of zoology) is due to their structure. Most of them are represented by unicellular forms, but there are also colonial ones. An example of the latter is the circular ciliate infusoria of the dog. They have the appearance of attached stalks and are physiologically related.
Both the shape of the cells and the sizes of the protozoa differ in great variety. So, euglena is elongated, plasmodium is rounded, and the infusoria resembles a shoe. The cage of foraminifera and arcellas is protected by a shell of silica and calcium carbonate. But the shape of the amoeba is generally impossible to describe - it is not permanent.
The sizes of protozoa vary from 3 to 150 microns. Despite the cellular level of development, they independently carry out all physiological processes. These are heterotrophic nutrition, regulation of osmotic pressure, reproduction by dividing in two, diffuse respiration, active movement in space.
The simplest soil
We begin to consider the variety of protozoa with soil inhabitants. They settle in water droplets. Soil and naked amoebae, ciliates, flagellates and rootstocks are unicellular soils. Their characteristic feature is the ability to create cysts.
During this process, the cell forms a dense protective sheath, stops moving. It reduces the amount of water and slows down metabolic processes. There are cases that in the cysts stage, the simplest remained until 20 years. With the onset of a favorable period, the shell collapses and life activity is activated.
Many single-celled have adapted to life in other organisms. However, they can even benefit the owner. For example, flagellates live in the intestines of termites, which break down fiber to simple carbohydrates.Without them, insects will simply die from hunger.
But among the variety of protozoa known and those that are true parasites. One of them is Plasmodium Malaria. Initially, his cells enter the bloodstream of a person when a mosquito bites. Moving through the vessels, the parasite enters the liver, where it actively multiplies. The place of his next dislocation are red blood cells - red blood cells. Plasmodium destroys them, while releasing into the blood poisonous products of metabolism. The consequences for a person are fever, pain in the joints and muscles, fever. With the active development of the disease, renal failure occurs, which can be fatal.
Parasitic protozoa also include dysenteric amoeba, trypanosomes, and Toxoplasma. They all inhabit the organs of mammals, humans, causing their destruction.
Acquaintance with a variety of aquatic protozoa
The conclusions about the ability of unicellulars to adapt to different conditions are unambiguous: they easily adapt to dwelling in any environments. The simplest bodies of water are no exception. Here they float freely with the help of flagella and cilia.Freshwater single-celled are the source of food for other animals. The simplest ones living in the water column belong to a special ecological group. It is called plankton. Organisms that are at the bottom, are included in another group - benthos. Typical freshwater single-celled cells are amoeba proteus, ciliate infusoria, Arcellus vulgaris, euglena green.
Many single-celled and in the seas. These are foramenifera and radiolarians. Their cells are located inside the sinks, which have one large hole - the mouth. Out of it come numerous organelles of movement - pseudopods. Together, they form a fishing net, through which the simplest capture food particles.
The variety and significance of the simplest
Unicellular organisms are an integral link in the food chain. Inhabitants of freshwater bodies prefer different water pollution. Therefore, they are used as an indicator for determining the sanitary condition.
The shells of the simplest - the basis of rocks. So, limestone was formed from the skeleton of the foramenifer many years ago. Geologists use these organisms as a scale to determine the age of sedimentary minerals.
With the help of soil inhabitants decompose organic matter.Moreover, this activity is of global importance. Unicellular soils directly participate in soil formation processes.
The variety of protozoa regulates the number of other organisms. Parasitic species cause severe diseases: malaria, toxoplasmosis, leishmaniasis. Thus, representatives of the subcellularity Unicellular, taking part in the circulation of substances, have both positive and negative effects.