The air we breathe is twenty-one percent oxygen, an
amount higher than on any other known world. While we
may take our air for granted, Earth was not always an
oxygenated planet. How did it become this way? Oxygen is
the most current account of the history of atmospheric
oxygen on Earth. Donald Canfield - one of the world's
leading authorities on geochemistry, earth history, and
the early oceans - covers this vast history, emphasizing
its relationship to the evolution of life and the
evolving chemistry of the Earth. With an accessible and
colorful first-person narrative, he draws from a variety
of fields, including geology, paleontology,
geochemistry, biochemistry, animal physiology, and
microbiology, to explain why our oxygenated Earth became
the ideal place for life. Describing which processes,
both biological and geological, act to control oxygen
levels in the atmosphere, Canfield traces the records of
oxygen concentrations through time. Readers learn about
the great oxidation event, the tipping point 2.3 billion
years ago when the oxygen content of the Earth increased
dramatically, and Canfield examines how oxygenation
created a favorable environment for the evolution of
large animals. He guides readers through the various
lines of scientific evidence, considers some of the
wrong turns and dead ends along the way, and highlights
the scientists and researchers who have made key
discoveries in the field. Showing how Earth's atmosphere
developed over time, Oxygen takes readers on a
remarkable journey through the history of the
oxygenation of our planet. |
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