Evolutionary development of life forms is studied via phylogenetic analysis. Such study builds our tree of life. Our knowledge is enriched by the fossils that paleontologists reconstruct for us, augmenting our abstract tree of life with visual information.
In September 2015, a digital version of our phylogenetic tree was published, documenting some 2.3 million species and their evolutionary relationships. There are thought to be on the order of tens of millions of species, so this is but a start. As more documented analysis of other species becomes available, this tree will expand to include them.
The biological evolutionary processes all derive from the organic chemistry of the cell and are further revealed to us through study of embryonic development.