There is a healthy tradition of making timelines of the history of life on earth as a a classroom activity, and I have been wanting to do this for a long time. There is also good evidence that active learning improves student learning outcomes in all STEM fields.
The Earth is 4.54 billion years old (Ga), and life on earth was microbial for almost all of this time. Viruses also had their origins in the RNA world that precluded the evolution of cellular life, meaning that even before “true” life was formed, microbes were the sole life forms.
In this activity, I set up a large timeline in the front of the room with signs that students helped hang on the timeline, and a smaller set of cards (the same as the signs, as pictured below) so students could arrange them in order at their chairs.
The full resolution handout of the cards and the associated handout is linked below, along with some challenge questions about the history of life on earth.