What is an Individual Organism? A Multilevel Selection Perspective

  title={What is an Individual Organism? A Multilevel Selection Perspective},
  author={Henri Folse and Joan Roughgarden},
  journal={The Quarterly Review of Biology},
  pages={447 - 472}
Most biologists implicitly define an individual organism as “one genome in one body.” This definition is based on physiological and genetic criteria, but it is problematic for colonial organisms. We propose a definition based instead on the evolutionary criteria of alignment of fitness, export of fitness by germ‐soma specialization, and adaptive functional organization. We consider how these concepts apply to various putative individual organisms. We conclude that complex multicellular… 

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