Plants and Oxygen

Plants and Oxygen

Plants and oxygen: By one billion years ago, plants, working cooperatively, had made a stunning change in the environment of the Earth. Since the oceans were by now filled with simple green plants, oxygen was becoming a major constituent of the Earth’s atmosphere, altering it irreversibly from its original hydrogen rich character and ending the epoch of Earth history when the stuff of life was made by non-biological processes.

But oxygen tends to make organic molecules fall to pieces; and despite our fondness for it fundamentally a poison for unprotected organic matter.

Photo by Elena

The transition to an oxidizing atmosphere posed a supreme crisis in the history of life. A great many organisms, unable to copy with oxygen, perished.

A few primitive forms, such as the botulism and tetanus bacilli, manage to survive even today only in oxygen free environments. The nitrogen in the Earth atmosphere is much more chemically inert and therefor much more benign than oxygen. But it, too, is biologically sustained. Thus 99 percent of the Earth’s atmosphere is ob biological origin.

Green plants generate molecular oxygen. Illustration . © Megan (Elena)