Headings The Atmosphere Search Questions
gcsescience.com 7 gcsescience.com
History (continued).
The evolution of green plants and
the presence of oxygen
in the atmosphere produced
further changes.
Ammonia and methane
would have reacted with oxygen
producing carbon dioxide and
water (from methane)
and nitrogen and water from ammonia.
Ammonia would also have decomposed in the presence of
strong ultraviolet light
from the sun, giving more nitrogen and
hydrogen.
Nitrifying bacteria
acted on ammonia to produce
nitrates for plant growth,
and denitrifying bacteria added nitrogen to the atmosphere (nitrogen cycle).
The proportion of nitrogen in the atmosphere steadily
increased.
The increase in oxygen
and the presence of the ozone layer in
the atmosphere allowed new and more complex life
forms to evolve.
Headings The Atmosphere Search Questions
gcsescience.com Contents The Periodic Table Index Quizzes gcsescience.com
Copyright © 2008 Dr. Colin France. All Rights Reserved.