Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Multicellular Organisms

Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1031-5

Synonyms

Definition

Multicellular organisms are those composed by multiple cells. They are classified in 13 major groups of terrestrial living beings, including animals, plants, fungi, ciliates, algae, and foraminifera. The number of cells per organism range from some tens to up to several million. The cells in a multicellular organism are usually varied, differentiated, and specialized.

Overview

The evolutive path toward multicellularity seems to be not particularly challenging, as different groups of multicellular organisms seem to have evolved independently (Rokas 2008). Also, it is possible to follow the invention of multicellularity in separate major clusters of organisms within the 13 main groups, as they are well known to be polyphyletic. In general, aquatic organisms became multicellular because the daughter cells did not separate completely during cell division, while land multicellular organisms formed by the aggregation of a...

Keywords

Atmospheric oxygen Body size Cambrian Ediacara Multicellular Paleoproterozoic Specialization 
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References and Further Reading

  1. Bonner JT (1999) The origins of multicellularity. Integr Biol Issues News Rev 1(1):27–36CrossRefGoogle Scholar
  2. Donoghue PCJ, Antcliffe JB (2010) Early life: origins of multicellularity. Nature 466:41–42CrossRefADSGoogle Scholar
  3. Michod RE, Roze D (2001) Cooperation and conflict in the evolution of multicellularity. Heredity 86:1–7CrossRefGoogle Scholar
  4. Niklas KJ, Newman SA (2013) The origins of multicellular organisms. Evol Dev 15:41–52CrossRefGoogle Scholar
  5. Rokas A (2008) The origins of multicellularity and the early history of the genetic toolkit for animal development. Annu Rev Genet 42:235–251CrossRefGoogle Scholar
  6. Smith JM, Szathmáry E (1997) The major transitions in evolution. Oxford University Press, New YorkGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.NASA Ames Research CenterMoffett FieldUSA