Chemistry (Combined Science) · GCSE · AQA · AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher · Specification point · 5.9.1.3 · Chemistry of the atmosphere · The composition and evolution of the Earth's atmosphere
Read Notes
Read clear notes for this topic.
Exam Questions
Coming soon
Flashcards
Flip through flashcards to lock it in.
Lesson
Coming soon
Ask Sage
Get help from Sage on this topic.
5.9.1.3 How oxygen increased
| Content | Key opportunities for skills development |
|---|---|
Algae and plants produced the oxygen that is now in the atmosphere by photosynthesis, which can be represented by the equation: |
Algae first produced oxygen about 2.7 billion years ago and soon after this oxygen appeared in the atmosphere. Over the next billion years plants evolved and the percentage of oxygen gradually increased to a level that enabled animals to evolve.
WS 1.2 An opportunity to show that aquatic plants produce oxygen in daylight. |