An Atlas of Development of the Sea Urchin Echinometra Lucunter Utilizing Differential Interference Contrast, Light, and Scanning Electron Microscopy
Date of Award
2003
Document Type
Thesis
Degree Name
Bachelors
Department
Natural Sciences
First Advisor
Morrill, John
Keywords
Sea Urchin, Echinometra lucunter, Development
Area of Concentration
Biology
Abstract
The development of the sea urchin Echinometra lucunter has not been studied due to the fact its egg is highly pigmented. In this study, sections of embryos and whole embryos viewed with DIC, light, and SEM were used to observe development. In contrast to other species, the blastocoelic cavity of Echinometra lucunter expands during morphogenesis. The cleavage cavity widens during primary mesenchyme cell (PMC) ingression, one to two cleavage cycles before the embryo hatches from the fertilization envelope. During the mesenchyme blastula stage, the PMCs appear rounded up in rows from the hyaline layer to the blastocoel, ingressing into the blastocoel in rows appearing as a 'basket'. Primary invagination begins with the formation of bottle cells that cause the elongated vegetal plate cells to buckle into the blastocoel. The short, wide archenteron, or primitive gut, now resides within the blastocoel. Secondary elongation of the archenteron is limited due to the close proximity of the archenteron to the animal pole following primary invagination. Ventral curving of the prism is concurrent with thickening and stretching of the triradiate spicules. By the 2 arm pluteus, the larval gastrointestinal tract and skeleton are formed. A self sufficient 4 arm pluteus larvae is the result of early development.
Recommended Citation
Marcus, Lauren, "An Atlas of Development of the Sea Urchin Echinometra Lucunter Utilizing Differential Interference Contrast, Light, and Scanning Electron Microscopy" (2003). Theses & ETDs. 3266.
https://digitalcommons.ncf.edu/theses_etds/3266
Rights
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