The Major Transitions in Evolution

The Major Transitions in Evolution is a book written by John Maynard Smith and Eörs Szathmáry (Oxford University Press, 1995).

Transitions described in the book
Transition from:	Transition to:	Notes
Replicating molecules	"Populations" of molecules in compartments	Can't observe
Independent replicators (probably RNA)	Chromosomes	RNA world hypothesis
RNA as both genes and enzymes	DNA as genes; proteins as enzymes
Prokaryotes	Eukaryotes	Can observe
Asexual clones	Sexual populations	Evolution of sex
Protists	Multicellular organisms — animals, plants, fungi	Evolution of multicellularity
Solitary individuals	Colonies with non-reproductive castes
Primate societies	Human societies with language, enabling memes^{[dubious – discuss]}^[1]	Sociocultural evolution

Maynard Smith and Szathmary identified several properties common to the transitions:

Smaller entities have often come about together to form larger entities. e.g. Chromosomes, eukaryotes, sex multicellular colonies.
Smaller entities often become differentiated as part of a larger entity. e.g. DNA & protein, organelles, anisogamy, tissues, castes
The smaller entities are often unable to replicate in the absence of the larger entity. e.g. Organelles, tissues, castes
The smaller entities can sometimes disrupt the development of the larger entity e.g. Meiotic drive (selfish non-Mendelian genes), parthenogenesis, cancers, coup d’état
New ways of transmitting information have arisen.e.g. DNA-protein, cell heredity, epigenesis, universal grammar.

[edit] Notes

^ It is rather dubious that John Maynard Smith resorted to the notion of meme, introduced by Richard Dawkins in his book The Selfish Gene (1976). In fact John Maynard Smith expressed strong critical reserves on the notion of meme (Smith, John Maynard. "Genes, Memes, and Minds." New York Review of Books, November 30, 1995, 46-48)