Units and passages: A view for evolutionary biology and ecology

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Many authors, including paleobiologists, cladists and so on, adopt a nested hierarchical viewpoint to examine the relationships among different levels of biological organization. Furthermore, species are often considered to be unique entities in functioning evolutionary processes and one of the individuals forming a nested hierarchy. I have attempted to show that such a hierarchical view is inadequate in evolutionary biology. We should define units depending on what we are trying to explain. Units that play an important role in evolution and ecology do not necessarily form a nested hierarchy. Also the relationships among genealogies at different levels are not simply nested. I have attempted to distinguish the different characteristics of passages when they are used for different purposes of explanation. In my analysis, species and monophyletic taxa cannot be uniquely defined as single units that function in ecological and evolutionary processes. The view discussed in this paper may provide a more general basis for testing competing theories in evolution, and provide new insights for future empirical studies.

Original languageEnglish
Pages (from-to)415-434
Number of pages20
JournalBiology and Philosophy
Issue number4
Publication statusPublished - 1987 Oct 1
Externally publishedYes


  • Units
  • causality
  • ecology
  • evolution
  • hierarchy
  • lineages
  • ontology
  • phylogeny
  • pluralism
  • species

ASJC Scopus subject areas

  • Philosophy
  • Agricultural and Biological Sciences(all)
  • History and Philosophy of Science


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