The diagrams given below represent the relationship between a mouse and a physiological process that occurs in green plants. Bell jar A contains a mouse with a green plant; bell jar B contains a mouse with a burning candle and no plant. Study the diagrams and answer the questions that follow: The diagrams given below represent the relationship between a mouse and a physiological process that occurs in green plants. Bell jar A contains a mouse with a green plant; bell jar B contains a mouse with a burning candle and no plant. Study the diagrams and answer the questions that follow:
What is the significance of the process as stated in (i) for life on earth?
Topic: Significance of photosynthesis
Answer
- It provides FOOD for all organisms. Green plants are the PRODUCERS at the base of every food chain, and every other organism depends directly or indirectly on the food they make.
- It provides the OXYGEN in the atmosphere, without which aerobic respiration would be impossible. It also removes carbon dioxide, keeping its level in the air in balance.
Give BOTH reasons — FOOD and OXYGEN. The oxygen point is the one candidates forget, and it is the one this experiment actually demonstrates.
THE FOOD ARGUMENT: a tiger eating a deer is ultimately living on the grass the deer ate, and therefore on photosynthesis. Every consumer, however far up the chain, is living on sunlight at one remove. Photosynthesis is the point at which the sun’s energy ENTERS the living world.
THE OXYGEN ARGUMENT: the earth’s early atmosphere had NO free oxygen at all. It accumulated as a by-product of photosynthesis over billions of years, and it made aerobic life — and the ozone layer — possible.