<p> The larval nutritional mode of marine invertebrates is an important life history trait that has strong effects on their ecology and evolution. Increases in egg size and transitions from feeding to nonfeeding larvae have happened repeatedly. In Spiralia, a change in cytoplasm allocated to macromeres at the 8-cell stage (that could delay the development of a functional gut) may accompany these transitions. The first part of this thesis describes the development of the gastropod <i>Crepidula williamsi</i> and compares it to the closely related <i>C. fornicata,</i> with a focus on changes in allocation to macromeres and the development of a functional gut. The second part is a phylogenetic comparison of egg size and allocation to macromeres in 44 species of spiralians, which revealed a significant correlation between the two. A phylogenetic comparison like this one has not previously been done on the development of such diverse marine invertebrate taxa.</p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:1596978 |
| Date | 17 September 2015 |
| Creators | Jones, Caleb |
| Publisher | California State University, Long Beach |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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