177 1 year, J. Priestley, a British priest and chemist, conducted a closed bell jar test. He found that the candle in the closed bell jar with plants would not go out and the mouse would not suffocate. So in 1776, he suggested that plants can "purify" the air. But he can't repeat his experiments many times, which shows that plants can't always "purify" the air.

Dutch doctor J. Ingenhousz conducted many experiments on the basis of Priestley's research, and found that the reason why Priestley's experiments could not be repeated many times was that he ignored the role of light, and plants could only "purify" the air under light.

It is generally believed that J. Priestley was the discoverer of photosynthesis, and 177 1 was considered as the year of discovery of photosynthesis.

Extended data:

The earliest photosynthesis:

1990, a red algae fossil was found in the Canadian Arctic. This kind of red algae is the first known sexually propagated species on the earth, and it is also considered as the oldest ancestor of modern animals and plants. Before, there was no unified view on the age of red algae fossils. Most people thought that they lived 65.438+0.2 billion years ago.

In order to determine the age of this red algae fossil, the researchers went to baffin island to collect the black shale containing this red algae fossil, and analyzed its rhenium-osmium isotope dating. It is considered that the history of red algae fossils is 65.438+0.47 billion years.

On the basis of confirming the age of red algae fossils, the researchers used a mathematical model called "molecular clock" to calculate biological evolution events according to the mutation rate of genes. Their conclusion is that about 654.38+0.25 billion years ago, eukaryotes began to evolve chlorophyll which can be used for photosynthesis.

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