U 3 L 1 Evolution of the Atmosphere
respiration
the process by which oxygen combines with food to release energy and carbon dioxide
What force keeps our atmosphere from floating out into space?
gravity
meteorite
mass of stone or metal that has passed through the atmosphere and struck the earth's surface
meteoroid
mass of stone or metal traveling through space
The earth has fewer meteorite impacts because_____.
of the earth's atmosphere
photosynthesis
process by which plants use chlorophyll and energy from sunlight to manufacture food from carbon dioxide
cyanobacteria
single-celled photosynthetic bacteria
The first major source of oxygen gas was _____.
cyanobacteria
What would be the result if Earth's unique atmosphere did not exist?
Life would no longer be possible.
The atmosphere has many roles, including:
+provides gases for respiration and photosynthesis +provides food for life +provides protection from UV radiation and meteorites Xprovides a surface to build and live on +stabilizes a habitable temperature
Which of the following factors caused the early atmosphere to become thicker?
+volcanic outgassing +meteorite and comet impacts Xcyanobacteria Xbanded iron formations
ozone
a molecule composed of three oxygen atoms; absorbs UV radiation
In the paleoatmosphere, the primary gases were _____.
carbon dioxide, nitrogen, and water vapor