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3 (a) There are many theories about how life was formed on Earth - AQA - GCSE Chemistry - Question 3 - 2015 - Paper 1
Question 3
3 (a) There are many theories about how life was formed on Earth. Suggest one reason why there are many theories. 3 (b) In this question you will be assessed on usi... show full transcript
Worked Solution & Example Answer:3 (a) There are many theories about how life was formed on Earth - AQA - GCSE Chemistry - Question 3 - 2015 - Paper 1
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Step 2
Describe and explain how the surface of the early Earth and its atmosphere have changed to form the surface of the Earth and its atmosphere today.
Answer
The surface of the early Earth was dominated by volcanic activity, resulting in a landscape filled with lava and gases. Over time, as the Earth cooled, these volcanoes ceased to erupt, leading to the formation of a solid crust.
The early atmosphere was primarily composed of carbon dioxide and water vapour. As the Earth cooled further, water vapour condensed to form oceans, which in turn absorbed carbon dioxide from the atmosphere. This process significantly reduced the levels of carbon dioxide.
Additionally, the emergence of life, particularly through photosynthesis, contributed to the alteration of the atmosphere. Early plants and algae began to use carbon dioxide and release oxygen, transforming the atmosphere from one rich in carbon dioxide to one that is now dominated by nitrogen and oxygen. This shift has resulted in the Earth as we know it today, with a stable atmosphere suitable for a diverse range of life.