The early atmosphere was much different than today and unsuitable for life as it lacked oxygen for breathing and ozone to block harmful solar rays. Eventually, cyanobacteria produced oxygen through photosynthesis which reacted to form ozone in the atmosphere, allowing ozone to block solar rays and permitting plants to survive on land while producing more oxygen for other organisms to breathe. The modern atmosphere is predominantly nitrogen, oxygen, argon and carbon dioxide.
3. The Early Atmosphere
•Much different than our atmosphere today.
•Not suitable for life: No Oxygen to breathe and no Ozone to protect from sun’s rays.
4. The Process
Eventually, organisms called
Cyanobacteria started making
Oxygen photosynthetically.
That oxygen
was used to
create
Ozone.
Ozone blocked harmful
rays from the sun allowing
plants to survive on Earth’s
surface. Plants produce
Oxygen allowing
you and I to live
and breathe on
Earth.
5. Composition of the Atmosphere
The most abundant gasses in
our atmosphere are:
1. Nitrogen
2. Oxygen
3. Argon
4. Carbon Dioxide
78%
21%
.934% .036%
Composition of Gasses
Nitrogen Oxygen Argon Carbon Dioxide
The atmosphere also contains some solids and
liquids:
Dust Acids Ash
Salt Water Vapor
