Great Oxidation Event

High school (ages 12+)
Environment & Earth

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/great-oxidation-event

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the approximate onset of GOE?Around 2.4 billion years ago
2. What is the primary biological driver?Oxygenic photosynthesis by cyanobacteria
3. What was Earth's atmosphere like before the Great Oxygen Adventure?It was mostly made of gases like methane, ammonia, and carbon dioxide, with almost no free oxygen.
4. Who made the first oxygen in the atmosphere?Tiny cyanobacteria, also called blue‑green algae, used sunlight to split water and released oxygen as a waste product.

Anoxic Atmosphere: An atmosphere lacking significant amounts of free oxygen, characteristic of early Earth.
Oxygenic Photosynthesis: The biological process that uses sunlight to split water, producing oxygen as a byproduct.
Banded Iron Formations (BIFs): Layered sedimentary rocks formed by the precipitation of iron oxides from oxygenated ancient oceans.