C13 - The Earth's Atmosphere - 13.1, half of 13.2 Flashcards
In the early years of its existence, what do scientists believe covered the Earth?
Volcanoes that erupted lava and excreted gases into the atmosphere
What information did scientists use to try and reconstruct what Earth was like when it was first created?
The atmospheres of other planets in the solar system and from bubbles of gas trapped in ancient rocks
What gases did volcanoes excrete during the early years of Earth?
Water vapour, carbon dioxide and nitrogen
How were the oceans created?
When the Earth started to cool down, the water vapour excreted by the volcanoes condensed and formed the oceans by forming in the craggy beds of rock that had become the face of the Earth. It is also suggested that some of the water came from comets that rained down on the Earth and melted when they passed through the atmosphere
Once the Earth began to stabilise, what were the main substances that made up its atmosphere?
Mainly carbon dioxide, with some water vapour and nitrogen, and traces of methane and ammonia
What caused the significant increase in oxygen levels in our atmosphere?
Photosynthesis and the evolution of photosynthesising organisms
Similarly to the rise of oxygen, why has there been such a decrease in the amount of carbon dioxide within the atmosphere between billions of years ago and now?
Photosynthesis from early organisms took in carbon dioxide from the air and emitted oxygen, resulting in the amount of carbon dioxide decreasing significantly
How was coal formed?
Coal was formed through the trapping of ferns and other plant materials without oxygen when they died in swamps and were buried. Over millions of years they were compressed and coal was created
How were crude oil and natural gas formed?
Crude oil and natural gas were created when the remains of plankton were deposited in muds on the seabed and covered in sedimentary rock. Over millions of years they were compressed and natural gas and code oil formed
