Alternation of generations enables thaliaceans to colonize seas quickly, taking advantage of phytoplankton blooms resulting in large swarms. One of the generations is asexual with vegetative growth resulting in the sexual stage. The other generation is sexual, which produces the egg and sperm that fuse to make the asexual stage.
Thaliaceans show different strategies to ensure successful reproduction. Pyrosomatids develop eggs that, when fertilized, develop to hatching inside the zooid. Doliolids retain the tadpole larval stage of their benthic tunicate ancestors during development. Salpids retain both asexual and sexual stages and true embryonic connection (via a placenta) to the parent during development.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.