The_Major_Transitions_in_Evolution The_Major_Transitions_in_Evolution

The Major Transitions in Evolution - Definition and Overview

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
1. Replicating molecules to Populations of molecules in compartments Can't observe
2. Independent replicators (probably RNA) to Chromosomes
3. RNA as both genes and enzymes to DNA as genes, proteins as enzymes
4. Prokaryotes to Eukaryotes Can observe
5. Asexual clones to sexual populations — evolution of sex
6. Protists to multicellular organisms — animals, plants fungi
7. Solitary individuals to colonies with non-reproductive castes
8. Primate societies to Human societies with language, enabling memes

Properties common to the transitions:

  1. Smaller entities have often come about together to form larger entities. e.g. Chromosomes, eukaryotes, sex multicellular colonies.
  2. Smaller entities often become differentiated as part of a larger entity. e.g. DNA & protein, organelles, anisogamy, tissues, castes
  3. The smaller entities are often unable to replicate in the absence of the larger entity. e.g. Organelles, tissues, castes
  4. 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
  5. New ways of transmitting information have arisen.e.g. DNA-protein, cell heredity, epigenesis, universal grammar.
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