How Oxygen Increased (AQA GCSE Chemistry): Revision Notes
📚 Revision Notes
9.1.3 How Oxygen Increased
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The increase in oxygen in the Earth's atmosphere was a crucial step in the evolution of life.
The Role of Photosynthesis:
- Emergence of Plant Life:
- Around 2.7 billion years ago, algae and other early forms of plant life appeared.
- These organisms began to carry out photosynthesis, a process that uses sunlight to convert carbon dioxide and water into glucose and oxygen.
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Photosynthesis Reaction: The chemical equation for photosynthesis is:
- Oxygen Accumulation:
- As photosynthesis continued, it steadily increased the amount of oxygen (O₂) in the atmosphere.
- This buildup of oxygen over millions of years eventually enabled the development of more complex life forms.