from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The condition of having the body divided into metameres, exhibited in most animals only in the early embryonic stages of development.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The segmentation of the body into similar discrete units
- n. The matching of apparent color of objects with different spectral power distributions.
- n. structural isomerism
from the GNU version of the Collaborative International Dictionary of English
- n. The symmetry of a metameric structure; serial symmetry; the state of being made up of metameres.
- n. The state or quality of being metameric; isomerism due to different bonding patterns in two substances having the same molecular formula. Contrasted with
steroisomerismor optical isomerism. Also, the relation or condition of metameric compounds.
from The Century Dictionary and Cyclopedia
- n. In chem., a form of isomerism, that property of certain compound bodies by which they have the same chemical elements combined in the same proportion and with the same molecular weight, while differingin chemical properties.
- n. In zoology, a metameric condition; the state of being metameric; segmentation of the body of an animal along the primary or longitudinal axis, resulting in a series of more or less similar consecutive parts which are serially homologous. See metamere, antimere.
Sorry, no etymologies found.
For example, here's what Wikipedia has to say about bauplans and metamerism:
So, would the homeobox regulation of metamerism be considered as a "front-loaded" pre-adaptation?
March 20th, 2009 at 9: 52 am an interesting discussion for this group might be the evolution of metamerism, which seems to have been the crucial evolutionary innovation in both arthropods and vertebrates (not to mention most plants).
If it turns out that there are other possible mechanisms but that the homeobox regulatory mechanism was the least costly evolutionary speaking for primitive animals with out metamerism then MET gains additional plausibility
First I think we would all agree that we should all give a shout out to our own personal God for metamerism.
So, is metamerism part of the "front-loading" hypothesis?
Sean Carroll's book, Endless Forms Most Beautiful has a good, relatively simple description of how the homeobox regulatory mechanism is tied to metamerism.
In terms of evolutionary mechanisms (such as the origin and elaboration of metamerism), adaptations are the result of natural (or sexual) selection, and are what ID supporters point to as the things that an Intelligent Designer would design into an organism.
In both cases, it is of course possible to speculate endlessly on how metamerism might be regulated.
Like Vetustovermis, Kimberella has many structures crenellations that may have been gills, has a broad flat foot, showing metamerism, and its shell bears many impressions, which may be the remains of sclerites or spicules.