Everything you wanted to know about evolution by natural selection in short, easy to digest, episodes. Hosted, and produced by writer Rick Coste.
https://evolutiontalk.com/podcast/
The Beginning: Cyanobacteria
3.5 billion years ago microbial organisms appeared on the earth. These organisms combined, split, and combined some more, until the formation of microbes and single-celled algae. One of these single-celled algae-like organisms were cyanobacteria.