The significance of photosynthesis is described as under.
(1) It is the primary source of organic food and food energy (ATP) and oxygen for all forms of life, either directly or indirectly.
(2) Excess of sugars produced in photosynthesis are either stored in the form of carbohydrates or used in the biosynthesis of other organic compounds.
(3) In any ecosystem, green plants represent the most essential biotic components as they are the primary producers.
(4) Photosynthesis releases O2 and hence helps to purify air, and also maintains balance of O2 and CO2 in nature.
(5) Oxygenic photosynthesis was responsible for converting the totally anaerobic condition on earth into aerobic condition in the geological past.
(6) The fossil fuels e.g. natural gas, coal,petroleum(oil) etc are all energy rich materials of organic origin. The energy stored in all these fuels is basically the solar energy which was trapped and stored during photosynthesis in the geological past.