In the beginnings, the depressions on the earth were filled with water, and there was a heavy atmosphere of gases. The first living things [firstlings] to make appearance on the earth planet are plants, the aquatic algae- seaweeds.
“It is almost certain that the first thoroughly successful creatures were microscopically small, that they swarm about in the sea by means of vibrating lash of living matter, that they possessed chlorophyll…. Colouring matter which enabled them to use the power of sunlight, and they were nearer to plants than to animals.” [Arthur mee]
Green leaves in green plants are labs of chemical compositions that result in green plants manufacturing their own food nutrients for nourishment, energy, growth and reproduction.
“Beyond any doubt, the green leaf is the most marvelous laboratory in the world. For there, in perfect silence, is brought about the raising of simplicity into complexity, the making of the organic out of the inorganic. It is also the most important laboratory in the world, for all animals and human life practically depend on the nutritive material, the green leaf builds up.” [Arthur Mee].
In all green leaves exist chloroplast cells. Chloroplast is derived from two Greek words namely:
“Chloros” meaning green and “plastis” meaning one who forms. The green colouring or pigmentation of the leaf is known as chlorophyll. Chlorophyll too is derived from two Greek words, namely: “chloros” meaning green and “phyllon” meaning leaf. Hence chlorophyllon- chlorophyll- green leaf. Chlorophyll gives leaves this green colour [pigment]. A high concentration of chlorophyll discs is found in chloroplast [organelle] cells. The function of chlorophyll in chloroplast cells is to absorb, capture and trap light energy [sunlight] from the sun during the day. Sunlight is converted into chemical energy, then stored in the chloroplast cells, and used in the process of manufacturing food nutrients for the plants.
Photosynthesis is derived from two Greek words, namely; “photo” meaning light and “synthesis” meaning putting together or composition. Photosynthesis is a process by which green plants manufacture their food nutrients. The activity takes place in the chloroplast cells. Professor F.O Bowe sums up five factors or conditions in his mastery book on the Botany of the Living Plants that influence the process of photosynthesis, these are: Chlorophyll. Sunlight. Water and mineral salt. Carbon dioxide and optimum temperature.
Green plants use sunlight as chemical energy to split water into hydrogen and oxygen. The chemical energy is further used to synthesize the omnipresent simple substances. Carbon dioxide and hydrogen to form Carbon compounds. These complex substances of food are carbohydrates consisting of starch and sugars. Other nutrients manufactured by the green plants are fats, oils and proteins.
At the end of the process, Oxygen is given out [released] as a byproduct. Between plants, human beings and animals is an eternal cycle of exchanging gases. Human beings and animals use oxygen in combustion [oxidation] released by plants through the apertures of stomata. After combustion, human beings and animals release carbon dioxide in respiration. Carbon dioxide is also released in the decomposition [decay] of plants. The carbon dioxide in the atmosphere enters the leaves of plants through stomata, and is used in photosynthesis.