The cage is elementary, functional and genetic unit. All signs of life are peculiar to it, in suitable conditions the cage can maintain these signs and transfer them to the next generations. The cage is a basis of the structure of all live forms – monocelled and multicellular.
Instruction
1. Discovery of a cage was made by the English scientist Robert Hooke in the middle of the 17th century. Studying the structure of a stopper under a microscope, he found out that it consists of the bubbles divided by the general to partitions. In cuts of living plants he found the same cells. R. Hooke described the observations in the work "Micrography, or Some Physiological Descriptions of the Smallest Little Bodies by means of Magnifying Glasses".
2. Further researches were conducted by scientists to M. Malpigi and N. Gr. In their works the cage is designated as a fabric component. But the Dutch researcher Antonio van Levenguk made observations of unicells (infusorians, bacteria). Gradually there were ideas of a cage as an elementary organism.
3. Numerous researches helped T. Shvann to make some generalizations in 1838 – to formulate the cellular theory of the structure of organisms. This theory is fundamentals of such sciences as embryology, histology and physiology.
4. Provisions of the cellular theory still did not lose the relevance. Since the creation the theory was added and is the proof that all live – is uniform.
5. All life forms it is possible to divide into two nadtsarstvo as the structure of the making cages: prokariota and eukariota. Prokariota (doyaderny) – simple in structure also arose in the course of evolution earlier. Eukariota (nuclear cages) have more complex structure and appeared later, than prokariota.
6. Cages of all living organisms are organized by the uniform structural principles. From the environment the cage is separated by a plasmatic membrane. The cage contains cytoplasm in which organelles, cell inclusions and genetic material are located. Each organelle in a cage possesses the special role, and in general they define cell activity.
7. Prokariota – the cage which is not possessing a cellular kernel and internal membrane organelles. An exception are flat tanks at photosynthesizing types. Carry bacteria, cyanobacteria (blue-green seaweed) and the Archean to prokariota. The main contents of a cage-prokariota - viscous granular cytoplasm.
8. Eukariot – the cage possessing a cellular kernel which is delimited from cytoplasm by a nuclear cover. In cages eukariot there is a system of the internal membranes forming besides a kernel, some other organelles (endoplasmic network, Golgi's device, etc.). Besides, the vast majority has constant intracellular symbionts-prokarioty — mitochondrions, and for seaweed and plants — as well plastids.
9. The science does not know how and when there was the first cage on Earth. The earliest fossils of cages are found in Australia. Their age is estimated in 3.49 billion years. It is also unknown what substances served for construction of membranes of the first cages.