The Society for Integrative and Comparative Biology
Many-to-One Mapping of Form to Function: A General Principle in Organismal Design?1
1 Section of Evolution and Ecology, University of California, Davis, California 95616
We introduce the concept of many-to-one mapping of form to function and suggest that this emergent property of complex systems promotes the evolution of physiological diversity. Our work has focused on a 4-bar linkage found in labrid fish jaws that transmits muscular force and motion from the lower jaw to skeletal elements in the upper jaws. Many different 4-bar shapes produce the same amount of output rotation in the upper jaw per degree of lower jaw rotation, a mechanical property termed Maxillary KT. We illustrate three consequences of many-to-one mapping of 4-bar shape to Maxillary KT. First, many-to-one mapping can partially decouple morphological and mechanical diversity within clades. We found with simulations of 4-bars evolving on phylogenies of 500 taxa that morphological and mechanical diversity were only loosely correlated (R2 = 0.25). Second, redundant mapping permits the simultaneous optimization of more than one mechanical property of the 4-bar. Labrid fishes have capitalized on this flexibility, as illustrated by several species that have Maxillary KT = 0.8 but have different values of a second property, Nasal KT. Finally, many-to-one mapping may increase the influence of historical factors in determining the evolution of morphology. Using a genetic model of 4-bar evolution we exerted convergent selection on three different starting 4-bar shapes and found that mechanical convergence only created morphological convergence in simulations where the starting forms were similar. Many-to-one mapping is widespread in physiological systems and operates at levels ranging from the redundant mapping of genotypes to phenotypes, up to the morphological basis of whole-organism performance. This phenomenon may be involved in the uneven distribution of functional diversity seen among animal lineages.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  T. E. Higham The integration of locomotion and prey capture in vertebrates: Morphology, behavior, and performance Integr. Comp. Biol., July 1, 2007; 47(1): 82 - 95. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. M. Novack-Gottshall Using a theoretical ecospace to quantify the ecological diversity of Paleozoic and modern marine biotas Paleobiology, March 1, 2007; 33(2): 273 - 294. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. E. Higham Feeding, fins and braking maneuvers: locomotion during prey capture in centrarchid fishes J. Exp. Biol., January 1, 2007; 210(1): 107 - 117. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Van Wassenbergh, A. Herrel, D. Adriaens, and P. Aerts A test of mouth-opening and hyoid-depression mechanisms during prey capture in a catfish using high-speed cineradiography J. Exp. Biol., December 15, 2005; 208(24): 4627 - 4639. [Abstract] [Full Text] [PDF]
|
|