BSCI 207 Lecture Notes - Lecture 18: Lophotrochozoa, Monarch Butterfly, Tunicate
12 Oct 2016
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Document Summary
Life cycles vary in complexity between different organisms. Some life cycles are very simple: offspring are miniature versions of adults and eat the same foods as adults. A larval stage can allow motility in mature, sessile (immobile) adults. Larva can exploit other areas of the environment when it cannot eat the food source of the adult. This requires a rearranging of organ systems when transforming from a larva to an adult: this process is called radical metamorphosis. Decreases the energy input from the mother and allows the environment to feed the developing embryo. Sponges and coral are both examples of species that employs motile larvae to disperse a sessile species: larvae will swim in the water column and mature into a sessile organism. Tunicate larva: larva has a notochord structure and a rudimentary digestive system, the evolution of fish may have resulted from a tunicate-like larva changing its life cycle to become a permanent larva .
