Biological Sciences Seminar Series

Dr. Michael Boyle of the Smithsonian Institution presents:
"Comparative Developmental Life Histories in Sipuncula."

Boyle has utilized compound and confocal microscopy to investigate the variation in developmental morphology among three sipunculan species with contrasting life history modes. Their embryos and larvae differ in size, rate of development, timing and formation of muscle fibers and gut compartments, and the presence or absence of larval organs such as the apical tuft, prototroch, metatroch, and terminal organ. The amount of embryonic yolk provisioned within sipunculan-specific prototroch cells and body regions appears to correlate with life history mode. Different rates of development observed among these species indicate a shift from an ancestral, indirect planktotrophic life history mode toward a more rapid development through direct and indirect lecithotrophy.