Life Sciences

Oxygen Pollution

Billions of years ago the earth's atmosphere had no oxygen. Bacteria like the purple and red species seen in one section of the exhibit inhabited the world’s surface. They extracted energy from sulfur compounds. Over time, green bacteria, like those that are observed in another section of the exhibit, began to extract energy from water and produce oxygen as waste. By introducing oxygen into the atmosphere, the green bacteria poisoned large numbers of the other bacteria. But they also paved the way for oxygen breathing organisms—like humans.