Prehistory Obsession!

I am fully addicted to everything prehistoric! I'm currently working on an independent study project about Earth from 4bya to about 1mya

So far, some of my favorite things I learned:

- the first organisms were cyanobacteria, and because they developed photosynthesis, they caused the Great Oxidation Event (made the gases in the atmosphere habitable for more advanced life)

- there were multiple ice ages, including "Snowball Earth", when the entire surface of our planet was covered in ice

- sharks (another of my obsessions) were alive way before trees!

- a large portion of dinosaurs had feathers, including velociraptors (which, contrary to Jurassic World, were medium dog-sized at most and covered in feathers)

comment your favorite facts or points in prehistory!