Everything should be ultimately explainable in terms of the components of which it is composed. In the animal kingdom well over ninety-five percent of all recognized species are invertebrates, a distinction based on connective tissues, though most of our efforts have been directed towards vertebrates for reasons of convenience and closeness to man. Investigation of the various chemicals which make up plants and animals have been diverse, allowing us to get a general picture of what molecules to expect at each state of the evolutionary progression, but for now animal is the information complete, and for invertebrates the information is particularly sketchy. It would be convenient to have certain animals and plants completely known chemically, so that biological molecules subsequently discovered could be compared to these standards. Velella lata may be a candidate for such a standard, having a number of unique advantages. It occurs in the evolutionary chain at that point where a true multicellular animal begins, and it is the simplest animal from which genetically determined internal structural materials is conveniently isolated and purified.
In plants the connective tissue is considered to be almost entirely carbohydrate polymer and in vertebrates the connective tissue is considered to be almost entirely protein (amino acid polymer), while many invertebrates have almost even mixture of protein carbohydrate in an unknown relationship. Velella presents an opportunity to examine closely the nature of the protein and its relationship to the carbohydrate.
The carbohydrate of various invertebrates connective tissue matrices has been extensively studies and the structure and linkages reasonably well defined. Some questions remain regarding the length of the smallest oligosaccaride and the manner in which these are built up into higher levels of organization. Inorganic material (primarily in the form of calcium), lipid in small amounts, and moisture are also present in the invertebrate matrix. While calcium is generally considered to be in the form of the carbonate, the possibility that it is not all in this form awaits investigation, and the recent report that silicon is essential in the formation of chick connective tissues is interesting.5 Lipids are not a major component in connective tissues studied to date, and this is true of Velella also. This does not preclude, however, the possibility that lipids may play some role in the formation of membrane-like sheets which are observed in the laminations of various mollusk-arthropod matrices. Velella offers an opportunity to examine invertebrate connective tissue in an intense way to gain an understanding of the morphology and developmental dynamics which hopefully would be extensible to the vertebrate matrix.
| Identifer | oai:union.ndltd.org:pacific.edu/oai:scholarlycommons.pacific.edu:uop_etds-2771 |
| Date | 01 January 1972 |
| Creators | Gainey, Ralph Lee |
| Publisher | Scholarly Commons |
| Source Sets | University of the Pacific |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | University of the Pacific Theses and Dissertations |
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