What is photosynthesis? Who discovered photosynthesis?
Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose or other sugars. This process uses sunlight, water, and carbon dioxide to produce oxygen and energy-rich organic compounds.
The general equation for photosynthesis is:
6CO2 + 6H2O + Light Energy → C6H12O6 + 6O2
Where:
- CO2 is carbon dioxide
- H2O is water
- Light Energy is sunlight
- C6H12O6 is glucose (a sugar)
- O2 is oxygen
Photosynthesis is crucial for life on Earth as it produces most of the oxygen in the atmosphere and forms the base of most food chains.
The discovery of photosynthesis was not the work of a single person, but rather a series of contributions from several scientists over time:
-
Jan van Helmont (1640s): He conducted an experiment demonstrating that plants gain mass from water, not soil, though he didn't understand the role of carbon dioxide.
Science History Institute - Jan Baptist van Helmont -
Joseph Priestley (1772): He discovered that plants produce oxygen. He observed that a mouse could survive in a closed container with a plant, but not without.
Science History Institute - Joseph Priestley -
Jan Ingenhousz (1779): He expanded on Priestley's work by showing that plants only release oxygen in the presence of light and that they, like animals, also respire.
Science History Institute - Jan Ingenhousz -
Jean Senebier (1782): He discovered that plants absorb carbon dioxide from the air during photosynthesis.
Britannica - Jean Senebier -
Nicolas-Théodore de Saussure (1804): He demonstrated that water is incorporated into plants during photosynthesis and that the increase in plant mass is due to both carbon dioxide and water.
Biodiversity Heritage Library - Nicolas-Théodore de Saussure -
Julius Robert Mayer (1845): He proposed that plants convert light energy into chemical energy.
Britannica - Julius Robert Mayer -
Melvin Calvin and Andrew Benson (1940s): Mapped the biochemical pathway of photosynthesis.
Nobel Prize - Melvin Calvin
Therefore, the understanding of photosynthesis evolved through the combined efforts of numerous scientists over several centuries.