Building a multicellular organism.
Multicellular organisms appear to have arisen from unicells numerous times. Multicellular cyanobacteria arose early in the history of life on Earth. Multicellular forms have since arisen independently in each of the kingdoms and several times in some phyla. If the step from unicellular to multicellular life was taken early and frequently, the selective advantage of multicellularity may be large. By comparing the properties of a multicellular organism with those of its putative unicellular ancestor, it may be possible to identify the selective force(s). The independent instances of multicellularity reviewed indicate that advantages in feeding and in dispersion are common. The capacity for signaling between cells accompanies the evolution of multicellularity with cell differentiation.
Kaiser
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Department of Biochemistry and of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA. luttman@cmgm.stanford.edu
D005075:Biological Evolution; D002454:Cell Differentiation; D002455:Cell Division; D002462:Cell Membrane / Q000502:physiology; D002473:Cell Wall / Q000502:physiology; D000460:Chlorophyta / Q000502:physiology*; D000458:Cyanobacteria / Q000502:physiology*; D009231:Myxococcales / Q000502:physiology*; D010788:Photosynthesis; D015398:Signal Transduction