History of our Atmosphere Flashcards
What was Earth like 4.6 billion years ago?
Very hot, covered in volcanoes pumping gases into the atmosphere.
What did volcanoes release into the atmosphere?
Carbon dioxide, water vapour and nitrogen
What happened to the water vapour?
It condensed as the earth cooled and fell as rain. the rain formed the first oceans
How much oxygen was there in Earth’s early atmosphere?
Very little. Similar to the atmospheres on Mars and Venus.
How long ago did the first life begin on earth?
3.4 billion years ago
What type of organisms were the first to live on earth?
Simple organisms, similar to bacteria.
How did the first organisms survive?
They could break down chemicals as a source of energy.
What caused oxygen levels to gradually increase?
Simple organisms like algae evolved to produce energy by photosynthesis. Oxygen is produced as a waste product of photosynthesis
What other effect did photosynthesis have on the gases in the atmosphere
More carbon dioxide was removed (from photosynthesis).
What happened to the organisms that were adapted to high levels of CO2?
They died out as the oxygen levels rose.
