This section collects notes on evolutionary biology, with an emphasis on molecular evolution and the deep history of life. Notes cover landmark papers on phylogenetics (Woese’s three-domain system), the nature of universal common ancestors, and hypotheses about the origins of life in wet icy environments. This material appears here because of its relevance to computational biology: understanding evolutionary relationships and the origins of biological molecules provides important context for work on protein sequences, genomics, and astrobiology.