BIO 2135 Lecture Notes - Lecture 9: Gamete, Ventral Nerve Cord, Peripheral Nervous System
28 Sep 2016
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Document Summary
Unique muscle arrangement that is part of pseudocoelomate body plan. It only has longitudinal muscles and has single fluid filled space. They represent a form of simplicity of the organism that have miniaturized. In becoming really small, the body have become simplified. No need to retain coeloimc space, circulatory system because as they get smaller, the surface to volume ratio will work for them (diffusion) The condition of the pseudocoelom is unifying feature of the group: no longer monophyletic (scattered around, found out that pseudocoelomate is a common thing in the evolution of animal. Platyzoa have simplified their body plans (flatworms represent unique set of adaptations) Mesenteries are going to connect everything together to hold the organ system in place. In the flatworm, the coelom fills itself in and become acoelomate and there are whole bunch of reasons that they did that (advantage of feeding)
