BioConcepts

major transitionsgroße Transitionen (ger.)

• 1) Revolutionary steps in the evolution of a lineage, associated with a change in the life-form.
  
  category progress

  1965

  Each of the major transitions from water to land, from land to water, or into the air, was accompanied by basic reorganizations of the form and functions of the body. [...] Major transitions take place at times and places when and where physiologies and functions of particular organisms are appropriate for survival and reproduction in the available environments.

  Olson, E.C. (1965). The Evolution of Life: 150; 152.

  1968

  The author has attempted to present a synthesis of evolution of the vertebrates as recorded in their fossil record, and the physiological and functional changes that accompanied major transitions together with the lesser shifts accompanying adaptive radiations.

  Olson, E.C. (1968). [Rev.: Carter (1967). Structure and Habit in Vertebrate Evolution]. Quart. Rev. Biol. 43, 459-460: 459.
  

• 2) Steps in the evolution of life on earth in which smaller entities came about to cooperate, differentiate and form larger entities.
  category progress

  1995

  The major transitions [:]

  [1] Replicating molecules to populations of molecules in compartments

  [2] Unlinked replicators to chromosomes

  [3] RNA as gene and enzyme to DNA and protein (genetic code)

  [4] Prokaryotes to eukaryotes

  [5] Asexual clones to sexual populations

  [6] Protists to animals, plants and fungi (cell differentiation)

  [7] Solitary individuals to colonies (non-reproductive castes)

  [8] Primate societies to human societies (language)

  Szathmáry, E. & Maynard Smith, J. (1995). The major evolutionary transitions. Nature 374, 227-232: 228; cf. Maynard Smith, J. & Szathmáry, E. (1995). The Major Transitions in Evolution; id. (1999). The Origins of Life. From the Birth of Life to the Origin of Language: 17.