Students in Lower Elementary (grades 1-3) are deep into the Second Great Lesson: Coming of Life. As they study the end of the Archean Era, they see life develop on Earth. The first forms were bacteria, cyanobacteria (blue-green algae), which is still prevalent today. The oxygen released was very minute, and it took a billion years to make a difference. Scientists call this the "Boring Billion!" Check out the students making cyanobacteria inside a petri dish.