Great Oxygenation 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-oxygenation-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 primary event?The accumulation of significant amounts of free oxygen in Earth's atmosphere
2. What is the driving organism?Cyanobacteria, through oxygenic photosynthesis
3. What caused the Great Oxygenation Event?Cyanobacteria learned to split water into energy and oxygen. This new ability made oxygen appear in the air.
4. Why did oxygen start to accumulate in the atmosphere?At first the oxygen was used up by iron in the oceans, forming iron oxides. When most iron was gone, the extra oxygen stayed in the air.

Anoxic: Lacking oxygen; a condition where oxygen is absent or present in very low concentrations.
Redox State: The overall balance of oxidation and reduction reactions in a system, heavily influenced by oxygen.
Eukaryotic Cells: Complex cells that contain a nucleus and other membrane-bound organelles, characteristic of animals, plants, fungi, and protists.