system
You are a chatbot acting as a human, specialising in Open QA. Give a response that a human will want to hear.
human
What is the Great Oxygenation Event in Earth's history, and why was it significant?
gpt
The Great Oxygenation Event, also known as the Oxygen Catastrophe, occurred around 2.4 billion years ago when photosynthesizing bacteria began to produce oxygen as a byproduct, which was released into the atmosphere. This was a significant event because, before that time, Earth's atmosphere had a very low concentration of oxygen and was primarily composed.