Cell Theory

The cell theory, one of the most general and basic concept in biology, is formulated from the findings and ideas of the several scientists.

    In 1839, the German zoologist, Theodor Schwann, and the botanist, Mathias schleiden,  who were both working in their own, stated clearly that the bodies of all animals and plants are composed of cells and the products of cells. Cells were then commonly described as 'units of life' and ' the building blocks from which living organisms are made'. Biologists also realised that cells are not only the structural but also functional units of living organisms. In 1855, another German biologist, Rodolf Virchow, stated that 'all cells come from cells'.

    In the present century, studies connected with viruses and bacteria opened up the field of molecular biology. Scientist have now shown that information about cells ' make up,' is in the nucleic acids (deoxyribonucleic acid, DNA, and ribonucleic acid, RNA) of a cell.

   This information is passed on from the one generation to the next when the cell or organisms reproduces.

   Biologists have opposing views on which is the most important living entity:

• the cell? Or

• the whole organism?

    Some feel that the cell is the most important unit, while the organism is just a collection of cells working together in a coordinated manner. Others have proposed the organsimal theory where the whole organism is considered as the most important entity, with cells as mere sub-units.

   To decide which is more important, we could say that ' cells give rise to organisms', so they are more important. On the other hand, we can look at the maximal achievements of 

• cells living as independent units, and 

• complex multicellular organisms.

To use analogy: compare the functional efficiency of an independent cell and the multicellular organisms to that of s solitary bee and a colony of honey need respectively. We see that only multicellular organisms can attain maximal function efficiency. In addition, higher biological properties like emotions and intelligence only emerge at the multicellular organism level. These are the properties that account for the success of organisms.