Geology

Geology
The 366 daily episodes in 2014 were chronological snapshots of earth history, beginning with the Precambrian in January and on to the Cenozoic in December. You can find them all in the index in the right sidebar. In 2015, the daily episodes for each month were assembled into monthly packages (link in index at right), and a few new episodes were posted from 2015-18. You may be interested in a continuation of this blog on Substack at this location. Thanks for your interest!

Wednesday, January 15, 2014

January 7: Photosynthesis begins

By Richard I. Gibson

Once could argue that the most important event in the history of the Earth after its formation was the beginning of photosynthesis, about 2.7 billion years ago. This development by microscopic plants paved the way for oxygen to enrich the atmosphere, and allowed for oxygen-dependent animal life, including humans.

Even after oxygen began to accumulate in the atmosphere, it was many hundreds of millions of years, and many complex chemical reactions before the atmosphere was anything like it is today. And the growing concentration of oxygen was a serious crisis for the first life that appeared on earth—so much so that such life is relegated to obscure corners of the planet today.


Drawing by At09K9 via Wikipedia under Creative Commons license.

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