There are more than 7000 types of infusorians, but the most known of them – a paramecium caudatum. All these unicells are covered with eyelashes. Most of them lives in salty or fresh water, but some types settle in a stomach of ruminant mammals, promoting thereby cellulose digestion.
Instruction
1. A paramecium caudatum – the fast-floating elementary 0.1-0.3 mm long. She lives in reservoirs with the polluted water, and her body covered with longitudinal ranks of short eyelashes reminds a small shoe. Thanks to a dense outer layer of cytoplasm the infusorian keeps a constant form.
2. Numerous eyelashes of an infusorian in structure are similar to zhgutik of an euglena green and a volvox. By means of their wavy movements the shoe moves in water thickness the front end forward.
3. The monocelled animals moving by means of eyelashes are carried to a class of infusorians. For the first time such protozoa were found in the water infused on herbs. The word "infuzum" from which there was a name of infusorians, "tincture" means.
4. From the front end of a body to the middle the shoe has a fillet with longer eyelashes. On its back end the oral opening which proceeds a tubular throat is located. Fillet eyelashes continuously move, "adjusting" water and food parts to a mouth of an animal. The main food of an infusorian – a bacterium.
5. In shoe cytoplasm around bacteria it is formed digestive vacuoles, digesting a food particle due to allocation in it digestive juice. As well as at other protozoa, for example, of an amoeba, cytoplasm of an infusorian is in the constant movement.
6. With cytoplasm current digestive vacuoles, having come off a throat, it is carried on a body of a paramecium caudatum, promoting uniform digestion of nutrients. The undigested remains of food come to light through a poroshitsa of monocelled.
7. Allocation of harmful products of exchange at an infusorian happens by means of two sokratitelny a vacuole. One of them is located in front, another – behind. Being alternately reduced at an interval of 20-25 seconds, they throw out excess of water with unnecessary substances which gather in shoe vacuoles on the bringing tubules.
8. In cytoplasm of the elementary there are two kernels – small and big. The leading role in reproduction is assigned to a small kernel, and big regulates processes of food, allocation and the movement.
9. The infusorian, as well as an amoeba, division of a body in two breeds. And at first the small kernel, then big shares, and cytoplasm is already drawn only then. In each of two young shoes there is about one sokratitelny vacuole, and the second vacuoles and the system of tubules grow anew. Young infusorians eat and grow, and in a day division repeats.
10. Infusorians have primitive irritability. It is traced on experiments with addition in water of a kristallik of salt and infusion with bacteria. In the first case the animals will try to departure far away from salt solution, harmful to them, in the second, on the contrary, will gather around the favourite food.