Understand that theories regarding the composition and formation of the Earth's early atmosphere have developed over time.
Explain why evidence for the early atmosphere is limited due to the immense time scale of 4.6 billion years.
Describe the theory that intense volcanic activity during the Earth's first billion years released gases that formed the early atmosphere.
Explain how water vapour released by volcanoes condensed to form the oceans.
Compare the hypothesised early Earth atmosphere to the current atmospheres of Mars and Venus, noting it consisted mainly of carbon dioxide with little to no oxygen gas.
Describe how volcanic activity also produced nitrogen that gradually built up in the atmosphere, alongside small proportions of methane and ammonia.
Explain how the formation of oceans led to a reduction of carbon dioxide in the atmosphere, as it dissolved in the water and precipitated as carbonates to form sediments.
Interpret evidence and evaluate different theories about the Earth's early atmosphere when provided with appropriate information.
