The Earth's Atmosphere Flashcards
For the last 200 million years, what have the proportions of different gases in the atmosphere been?
The same
How much of the atmosphere is nitrogen?
About 80%
How much of the atmosphere is oxygen?
About 20%
What is a small proportion of the atmosphere made up of?
Various other gases like CO2, water vapour and the noble gases
What was there during the first billion years of the Earth’s existence?
Intense volcanic activity
What did the intense volcanic activity at the beginning of the Earth’s existence create?
The early atmosphere
What did the water vapour in the early atmosphere do?
Condense to form oceans
One theory about how the early atmosphere was formed says that…
The Earth’s atmosphere was mainly CO2 and there was little O2, with some water vapour and small proportions of methane and ammonia
Which 2 planets have similar atmospheres to the Earth’s early atmosphere, according to one theory?
Mars and Venus
One theory as to how life was formed involves the interaction between…
Hydrocarbons, ammonia, and lightening
What produced the oxygen that is now in the atmosphere? Through was process?
Plants and algae, photosynthesis
What happened to most of the carbon from carbon dioxide in the air?
It gradually became locked up in sedimentary rocks as carbonates (like limestone) and fossil fuels
What also acts as a reservoir for carbon dioxide?
Oceans
What does an increased amount of carbon dioxide in the oceans have an impact on?
The marine environment
Nowadays, the release of carbon dioxide by burning fossil fuels increases…
The level of carbon dioxide in the atmosphere, which is thought to be causing global warming
