Plankton is a living floating mass. It is made up of billions of microscopic organisms. This term comes from the Greek language and means "wandering" or "going with the flow".
Water as a habitat
Among the huge variety of terrestrial animal and plant life, it is impossible to find organisms that could spend their entire lives in the air. Even skillful "flyers", such as swallows, can not always rush under the clouds. Indeed, during the period of nesting, incubation of eggs, hatching of chicks, they are tied to the ground, however, like other birds. Yes, birds are not able to fly forever, they periodically need rest. The situation is exactly the same with insects. They spend a relatively short time in the air element. All their most important life processes, such as nutrition, reproduction, development, take place on earth. The whole world of plants is also connected with the earth's surface, from the simplest unicellular to tree species. Aquatic organisms (hydrobios) have a completely different relationship with the environment. This is due to the fact that the physical properties of water and air are different. Water has a much greater density and gravity. It turns out that the lifting force of this medium is greater than that of air. Respectively,aquatic inhabitants are able to constantly (or at least for a long period of their lives) be in suspension in the water column, without contact with the bottom. For such organisms, the support is not the soil, but the aquatic environment itself. It is precisely to such living creatures “floating” in the water column that free-floating, or planktonic, organisms belong. In fact, plankton is a collection of such living creatures.
Composition and characteristics of "wandering" organisms
For the most part, plankton are very small animals and microscopic algae - not many of them can be seen with the naked eye. A characteristic feature of plankton organisms can be called a relatively weakly expressed ability to move independently. Most of them are devoid of any organs responsible for movement, and are in the full sense of the word a toy of the waves. Plant plankton owes its incredible lightness to being in limbo. Its weight is close to the weight of the water it displaces. However, animal plankton may contain organisms capable of independent movement. This is explained by the presence of various organs of movement, due to which they can swim very briskly. However, such movement is very limited. Microorganisms are not even able to resist the weakest flow of water. And all because the strength of their movement is negligible.
How are the organs of movement?
To begin with, it should be noted that animal plankton -these are the simplest crustaceans, as well as fish, lobsters and other organisms in the stage of embryonic development. German scientists conducted studies that showed that these animals "soar" in the water column is not at all passive. The crustaceans make very active movements at short intervals - they evenly wave their swimming antennae, like birds soaring in the air. The complete inactivity of the mentioned tendrils will lead to the inevitable lowering of the crustacean to the bottom of the reservoir. Other organs of movement in animal plankton operate on the same principle. For example, the rotatory apparatus that rotifers are armed with. In fact, planktonic animals can be compared to an airplane that is kept in the air thanks to the work of a propeller. With the cessation of rotational movement, they slowly glide and sink to the bottom.
Buffet
A very important factor for the survival of animal plankton is the fact that the primary source of food, the plant substances that make up the plankton, are dispersed in the water mass, and not attached to the bottom of the reservoir. Thanks to this, animals find their necessary food in abundance in the elements around them. Algae reserves are able to ensure their existence - this is quite enough to restore the forces that organisms spend on independent movement, necessary for soaring in the water. In addition, plankton (the photos above fully reveal this natural phenomenon) is a very dense mass, which, in turn,serves as a source of food for marine animals and fish. Let's say whales are big fans of this high-calorie food and its main consumers.
Conclusion
Summarizing, it should be noted that in the modern world the term in question has one more meaning - office "plankton". These are mental workers with a reduced creative component. They spend their lives in offices and other offices. Office plankton include: accountants, secretaries, managers and others. The origin of the offensive epithet is easy to explain: in fact, all these employees are just small fry. "Plankton", in a word.
