Infusoria shoe: structure and modes of reproduction

Infusoria shoe - a fairly common form, which is attributed to a group of protozoa. It dwells in fresh standing water reservoirs with a sufficient amount of organic materials, which they feed on. By the way, the structure of infusoria-shoes is considered to be the most complex of this group of organisms.

general characteristics

Infusoria shoe is a unicellular organism, the shape of which really resembles the sole of the shoe and is preserved due to the dense outer layer of the cytoplasm. The entire body of the animal is covered with a huge number of cilia, which are arranged in longitudinal rows. Their main function is movement.

Moves the infusoria of the shoe with a blunt end forward. Cilia move with a slight delay relative to each other. When moving, the body also rotates around the axis.

Between the cilia are the so-called trichocysts - small fusiform organelles, which perform the function of protection. Each trichocyst consists of a body and a tip, which in the presence of an irritant (collision, heating, cooling) shoots sharply.

Infusoria shoe: structure

The bulk of the body is the endoplasm, or the fluid part of the cytoplasm. The ectoplasm is closer to the cytoplasmic membrane, has a more dense consistency and forms a pellicle.

Digestion. The infusoria shoe feeds on bacteria and has a rather peculiar cellular digestive system. Closer to the anterior end of the body is a perioral funnel, the inner surface of which is covered with a complex system of cilia. The movements of the cilia create a flow, along with which microorganisms are sucked in. Further, the nutrient particles fall into the pharynx, which is also lined with cilia, and only then into the mouth. By endocytosis, nutrients enter the digestive vacuole. Residues are derived through a specific organelle - a powder.

Genetic material. Infusoria shoe has two nuclei - a large (macronucleus) and a small (micronucleus). The micronucleus contains a full set of genetic information and takes part in the sexual reproduction of the organism. Macronucleus is responsible for the synthesis of protein compounds.

Isolation and breathing. Infusoria shoe is able to exist even at very low concentrations of oxygen in water. Oxygen is absorbed by the entire surface.

As already mentioned, this protozoan organism lives in fresh water and because of the difference in concentrations it needs an osmoregulation system. The infusoria has two contractile vacuoles, anterior and posterior, to each of which a branched tubule system leads. Excess liquids and secondary metabolic products are collected in the tubules and the vacuoles released into the environment. Both organelles are contracted alternately, every 15-20 seconds.

Reproduction of the infusoria-shoe

For this organism it is characteristic both sexual and asexual reproduction.

Asexual reproduction is carried out by transverse division of the cell into two equal parts. In this case, the body remains active. Next are rather complex regeneration processes, during which each part of the body completes the necessary organelles.

Sexual relations between the two individuals are carried out by conjugation. Infusoria temporarily stick together, and between their surfaces formed a kind of bridge from the cytoplasm. Macronuclei of both organisms are destroyed, and small nuclei are divided by meiosis.

This field forms four nuclei with a haploid set of chromosomes. Further, three of them die, and the rest is divided by mitosis, forming two protonuclei - female and male. Organisms exchange "male" protonuclei. Then in each there is a fusion of two nuclei and the formation of the syncaria. Then mitosis passes, after which one of the nuclei formed becomes a macronucleus, and the second - a micronucleus.