The common amoeba lives in silt at the bottom of polluted ponds. It looks like a small, gelatinous, colorless lump that continuously changes its shape. Its body, represented by only one cell, consists of a semi-liquid cytoplasm with a vesicular nucleus, but despite this, the amoeba is capable of movement.
Instructions
Step 1
The semi-liquid cytoplasm of the amoeba is constantly moving. If the current of the cytoplasm rushes to any one point of the body, a protrusion appears in this place. Increasing in size, it becomes a pseudopod - an outgrowth of the body, where the cytoplasm flows. With the help of such pseudopods, the amoeba moves, therefore it is referred to the group of rhizopods (pseudopods outwardly resemble plant roots).
Step 2
In an amoeba, several pseudopods may appear, surrounding a food particle - another protozoan, algae, bacteria. From the cytoplasm surrounding the prey, digestive juice is released, and a digestive vacuole is formed, inside which food is digested. Some of the substances under the influence of the juice dissolve, are digested, and the nutrients obtained in this way seep from the vacuole into the cytoplasm of the amoeba. The release of undissolved residues occurs over the entire surface of the body.
Step 3
The amoeba breathes on the entire surface of the body with oxygen dissolved in water and penetrating into its cytoplasm. With the help of oxygen, complex food substances of the cytoplasm are decomposed into simpler ones. This process is accompanied by the release of energy necessary for the life of the simplest.
Step 4
Water from the environment surrounding the amoeba constantly penetrates into the cytoplasm of the protozoan. Metabolic products are removed from the animal's body not only through the surface of the body, but also through a special contractile vacuole. This bubble is gradually replenished with water with harmful substances, and from time to time its contents are thrown out.
Step 5
Thus, the amoeba receives food, water and oxygen from the external environment. In her body, they undergo a number of changes, and the digested food serves as material for building the body of the animal. Waste products are removed outside. This is how the metabolism takes place, without which the life of any organism on Earth is impossible.
Step 6
Reproduction of amoeba consists in the sequential division in two of the nucleus and cytoplasm. In this case, the contractile vacuole passes to one young amoeba, and in the other it is formed anew. During the day, the simplest can share several times.
Step 7
When unfavorable conditions (drought, cold weather) occur, the amoeba forms a cyst: its body is rounded, and a dense shell stands out on the surface. Then the animal leaves the cyst membrane, releases the pseudopods and again switches to an active lifestyle.
