The origin of novelties in evolution: evolution of the protoconch II of planktotrophic gastropod larvae

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dc.contributor.author Page, Alison Mary
dc.date.accessioned 2013-09-27T21:15:00Z
dc.date.available 2013-09-27T21:15:00Z
dc.date.copyright 2011 en_US
dc.date.issued 2013-09-27
dc.identifier.uri http://hdl.handle.net/1828/4966
dc.description.abstract My research tested hypotheses about the evolutionary origin of a novel feature by modification of development. The novelty is the growing larval shell of gastropod molluscs, which emerged when gastropod larvae acquired the ability to feed. One hypothesis states that the growing larval shell in the Heterobranchia is a continuation of the embryonic phase of shell secretion. The second hypothesis states that the larval shell in the Caenogastropoda may be a precocious juvenile shell. These hypotheses implicate heterochrony. To test these hypotheses, I examined ultrastructural features of the shell-secreting cells of two or three life history stages in a member of each of four clades of gastropods: the Patellogastropoda, Vetigastropoda, Caenogastropoda, and Heterobranchia. My results are consistent with the first hypothesis, but I found no ultrastructural support for the second hypothesis. These results provide the most comprehensive comparative data set on the ontogeny of shell-secreting cells for the Gastropoda. en_US
dc.language English eng
dc.language.iso en en_US
dc.subject Patellogastropoda en_US
dc.subject Vetigastropoda en_US
dc.subject Caenogastropoda en_US
dc.subject Heterobranchia en_US
dc.title The origin of novelties in evolution: evolution of the protoconch II of planktotrophic gastropod larvae en_US
dc.type Thesis en_US
dc.contributor.supervisor Page, Louise Roberta
dc.degree.department Dept. of Biology en_US
dc.degree.level Master of Science M.Sc. en_US
dc.rights.temp Available to the World Wide Web en_US
dc.description.scholarlevel Graduate en_US
dc.description.proquestcode 0433 en_US

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