page_title: Body plan
section_title: Cuvier, 1817
hierarchical_section_title: Body plan / History / Cuvier, 1817
caption_attribution_description: Español: Árbol de la vida según Haeckel, E. H. P. A. (1866).Generelle Morphologie der Organismen&#160;: allgemeine Grundzüge der organischen Formen-Wissenschaft, mechanisch begründet durch die von C. Darwin reformirte Decendenz-Theorie. Berlin.
context_page_description: A body plan, Bauplan, or ground plan is a set of morphological features common to many members of a phylum of animals. The vertebrate body plan is one of many: invertebrates consist of many phyla.
  This term, usually applied to animals, envisages a "blueprint" encompassing aspects such as symmetry, segmentation and limb disposition. Evolutionary developmental biology seeks to explain the origins of diverse body plans.
  Body plans have historically been considered to have evolved in a flash in the Cambrian explosion, but a more nuanced understanding of animal evolution suggests gradual development of body plans throughout the early Palaeozoic.
context_section_description: In his 1817 work, Le Règne Animal, the French zoologist Georges Cuvier combined evidence from comparative anatomy and palaeontology to divide the animal kingdom into four body plans. Taking the central nervous system as the main organ system which controlled all the others, such as the circulatory and digestive systems, Cuvier distinguished four body plans or embranchements:
  with a brain and a spinal cord (surrounded by skeletal elements)
  with organs linked by nerve fibres
  with two longitudinal, ventral nerve cords linked by a band with two ganglia below the oesophagus
  with a diffuse nervous system, not clearly discernible
  Grouping animals with these body plans resulted in four branches: vertebrates, molluscs, articulata (including insects and annelids) and zoophytes or radiata.
caption: Haeckel's 'Monophyletischer Stambaum der Organismen' from Generelle Morphologie der Organismen (1866) with the three branches Plantae, Protista, Animalia
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