GEO 103 Lecture 23: Marine World
31 Mar 2017
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Document Summary
The top part is the photic zone which is where most of the producers live. These producers utilizes light in order to produce energy. When these producers die, they fall to the bottom and is eaten by bottom dwellers in the benthos. The organic material can also be recycled, but some do get buried into the rocks after staying at the bottom for a long time. Cambrian period was time of great experimentation - many new animals evolving and moving into new niches. Nearly all invertebrate phyla evolved during cambrian - however many with few species. Trace fossils common but major skeletonized life included: Mass extinction at end of cambrian - never full recover. Possible factors include predators, competition, loss of habitat, climate change. Inarticulate brachiopods common - lacking tooth-socket hinge line on shells. Shells made of chitnophosphate - calcium phosphate plus organic compound chitin. Articulate brachiopods minor and did not diversify until ordovician.
