Fig. 1 Classification of elements in human organism in terms of abundance and use (Underwood e., 1962)

The general number of elements referred to as vital varies in wide ranges depending on the author. For instance, one of classical biochemists А. Lenindger assumed that such elements are only 22 (Table1) in all types of organisms.

Table 1

Vital elements in composition of organisms (according to а. Lenindger)

Elements forming the organic substances	Mono-atomic ions	Elements detected in trace amounts
Oxygen	Sodium	Manganese	Aluminum
Carbon	Potassium	Iron	Vanadium
Nitrogen	Magnesium	Cobalt	Molybdenum
Hydrogen	Calcium	Copper	Iodine
Phosphorous	Chlorine	Zinc	Silicon
Sulfur	-	Boron	-

According to P. Aggett’s classification, to four organogens (oxygen, carbon, hydrogen and nitrogen) and seven macroelements (phosphorous, sulfur, sodium, potassium, magnesium, calcium, chlorine) as important essential elements should be added nine more: iron, copper, zinc, manganese, chromium, selenium, molybdenum, iodine, cobalt. In total – 20 vital elements.

One of the outstanding scientists in microelement study V. Merts suggests to add to the 11 organogenes and macroelements (nobody argues about quantitative and qualitative composition of the group) the following elements, the excess or deficit of which is of significance for human health: iron, copper, zinc, chromium, selenium, molybdenum, iodine, cadmium, lead and mercury. Hence, 21 elements, but the components of the group are different.

According to more extensive interpretation suggested by Anke, to the essential microelements along with Aggett’s "classical" essential elements one should add "new" essential ones: fluorine, silicon, tin, vanadium, nickel, arsenic, cadmium, lithium, lead. 29 in total.

All these interpretation with respect to quantity, properties, and participation of different elements in metabolism of animal organisms are connected, in our opinion, with absence of systematic approach. Here one can repeat again that it is necessary to develop natural classification of chemical elements, – that would contribute, along with other factors, to elimination of similar contradictions. Such a classification is presented in A.V. Bgatov’s works in particular (1999).

Elements of primary life at the dawn of evolution

The organogens traditionally include, taking into account their general content in living matter (98,72 %), four elements: oxygen, carbon, hydrogen and nitrogen, – it is this succession should be named that resulting from their weight relationships (i.е. g/t).

In Table 2 based on the data of Bown and Fortesque the content of some elements in plants, animal and human organisms is shown (according to the reference book data «Human…, 1977).

Table 2