“Know thyself” the history of inscription began around 3-4 billion years ago, on this time we date the beginning of life on the Earth, in unicellular organism form. The common ancestor. After a long period, around 1 billion years ago, the multicellular organism was developed, this was a milestone, the process sped up and there was a possibility to different variations. About 500 millions years ago, the plants colonized the Earth and soon appeared the animals too, approximately 200 millions years ago the mammals and finally 100 millions years ago the birds, both from reptile-like lineages.

The theory of the common ancestor and phylogeny were known in many cultures, but it was established only after Darwin, who recognized, the Earth much more older than worldwide accepted few thousands years, that was a revolutionary thinking and the most important recognition. It is not possible to constrain the evolution in short time frame.

We need detailed, tangible evidences like buildings, written records etc. to understand few thousands years and even in this case the past it seems far mystic with insignificant effect as everybody lives in present. Millions and billions of years are incomprehensible with human scale. Thanks to the archaeological finds, the ancient worlds are not only in our imagination, but museums, scientific books, documentary films and laboratories. These theories were combined and finalized with molecular biology by DNA.

Skip the unicellular and analyze the multicellular, if we compare the plant and animal cell, we can find many identities and some differences in structure and components. The most important difference is in the function of cells. The plant cell is autotroph, mostly photo-autotroph, it means the plant cell able to produce complex organic compounds from simple inorganic molecules with sunlight using. Experiments of Priestley and Inghenous demonstrate the importance and understanding of process: light a candle, place under an inverted jar. The burning consumes the oxygen till the candle will be expired and finally there is only carbon-dioxide under the jar. Priestly add a glass of water with branch mint under the jar and observed, that the plant stay alive in these conditions. Two months later added a mouse and the mouse survived it. Inghenous continue the experiments and noticed: while the plant is growing, the weight of soil is permanent and the plant produce oxygen. Also observed, that sunlight is needed for this process. (At nighttime, without sunlight, the plant also breathe in oxygen and out carbon-dioxide, of course they produce much more oxygen than use up.

Nowdays, we already know, the key of process is the chlorophyll in the plant cell. This molecule is able to absorb and transfer the energy from sunlight to ongoing synthetic process in cell. The chlorophyll molecules are very sensitives, a small harmful impact in environment is enough to destroy these extremely important biomolecules.

It is visible, the chlorophyll is very similar to hemoglobin (heme part), except the center of the ring, in chlorophyll it is magnesium (Mg²⁺) in the heme it is iron (Fe²⁺).

The autotrophy present the mystic of evolution. The plant cell conform to the conditions, based on energy from sunlight, water, inorganic carbon-dioxide in atmosphere, able to insure the potential of life for animal. The animal cells are heterotroph, it means these cells only can use other organisms as energy and food source , thus all animals, include humans, depend on the plants, while enjoy the necessary oxygen, what is also produced by plants.

Summarize, the photosynthesis is vital for all life and the plants are the fundamental of the food chains on Earth.

The animals take advantage of the opportunity: develop motion and sensor systems. The Planet is not only live but livable ...