| dc.contributor.author | Cole, Alison G. | en_US |
| dc.date.accessioned | 2014-10-21T12:38:03Z | |
| dc.date.available | 2004 | |
| dc.date.issued | 2004 | en_US |
| dc.identifier.other | AAINQ94041 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/54655 | |
| dc.description | Cartilage is a type of connective tissue that is often considered restricted to vertebrates, however cartilaginous tissues are also found within invertebrates. Unfortunately, most definitions and classifications of cartilage suffer from a profound vertebrate bias. I find that cartilage is defined most precisely using histological criteria, considering as criteria the composition of the extracellular matrix and the presence of histologically distinct chondrocytes. I have undertaken a rigorous analysis of connective tissues from a number of representative invertebrate lineages using histology, immunochemistry, and developmental data. I find cartilage to be restricted to molluscs, polychaetes, and arthropods, whereas chondroid connective tissues (which have similar histological and structural properties to cartilage) are much more widespread amongst invertebrate lineages. I have expanded the classification system for cartilage to include a variety of vesicular cartilages, thereby accounting for the diversity of histologies exhibited by invertebrate cartilages. | en_US |
| dc.description | The degree of homology between invertebrate and vertebrate cartilages has been unclear; phylogenetic relationships between metazoan lineages have undergone a series of revisions in recent years, making the evolutionary relationships between cartilage from different lineages difficult to discern from phylogeny alone. I discuss the relationships between cartilage and other related connective tissues using a supertree phylogeny I created from analysis of metazoan molecular systematics, concluding that cartilages from all lineages likely derived independently from a common chondroid connective tissue; thus forming a family of tissues that can be considered homologous at a tissue-level. Although the precise relationships between cartilages within different lineages remains obscured by the imprecision of current metazoan systematics, patterns in the evolution of cartilage as a tissue type can be elucidated through comparisons of histology and development of invertebrate cartilages. | en_US |
| dc.description | I have identified a tendency within cephalopod molluscs and sabellid polychaetes towards reduction or loss of cartilages that accompanies decreases in body size. Developmental data collected from cephalopods---wherein cartilages are histologically most similar to vertebrate hyaline cartilage---illustrates that cartilage most often differentiates from uncondensed mesenchymal cells near the end of embryonic development. (Abstract shortened by UMI.) | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 2004. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Anatomy. | en_US |
| dc.subject | Biology, Animal Physiology. | en_US |
| dc.title | On the development and evolution of cartilage within non-chordate metazoa. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
