ZOO 2700 Lecture Notes - Lecture 29: Myoglobin, External Fertilization, Hermaphrodite
28 Mar 2018
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Document Summary
Live in burrows in the sediment= hard to find. Ciliated cells on proboscis to allow particles to move along it. Apomorphies stomocord: extension of foregut: thought as homology of rudimentary notochord (not actually though!) Food particles in proboscis transported to collar region. Sort of like a conveyor belt that sorts through sizes of particles (only accepts a certain size, rejects the others: cilia involved with this. Larval stages that they produce are planktonic: larvae can disperse to different areas when released into water column. Yolky eggs: short planktonic period, settlement. Indirect development with feeding larvae: torniaria larva, non-yolky. Pharyngeal gill slits: could be homologous to vertebrate embryal. Cephalochordates: much more similar to fish in terms of looks. Pharynx, in it is an endostyle: feeding organ to filter food out form the environment. Few reproductive events ar a certain time of year. Planktotrophic larvae: relatively small internal reserves and feed in the plankton.
