GEOL 200 Lecture Notes - Lecture 1: Ikonos
7 Dec 2015
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Most successful invertebrate phylum in the oceans: >1 million marine species strong, lightweight exoskeleton lightweight form of muscle full range of motion at each joint skeleton = chitin (fingernail), most molt (shed) periodically, as they age and grow, the shell cracks, animal crawls out of its shell, then generates new shell, new shell will be bigger than animal so it has room to grow. Asteroids sea stars: feed on molluscs and other organisms in intratidal zone, tube feet how they move, eating requires hydraulic system to move organs so it can dissolve food, wasting disease death of the stars gradually loses its arms. Echinoids sea urchin: roundish body with spikey spines, range in size and can be highly poisonous to not at all, very susceptible to certain pathogens, crinoids has a stem with roots that grip sea floor to move, is a filter feeder, looks like a flower.
