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					| Early Paleozoic Life |  
					| Lecture 18 3/30/98
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					| |  | Today we will look at the fossil record from the Early Paleozoic (Cambrian, Ordovician, and Silurian Periods) | 
 |  | These fossils record increasing diversity and changes in the structure of the in marine biosphere. | 
 |  | Throughout the Early Paleozoic diversity of life increases. | 
 |  | Increasing diversity appears to result from increasing specialization of faunas. | 
 |  | This specialization may have resulted as the earth's environment became more stable. | 
 |  | Openning of the Iapetous Ocean (proto-Atlantic) | 
 |  | Development of shallow seas on North America and Europe | 
 |  | most continental mass at low latitudes around the equator | 
 |  | Further breakup of continents into smaller pieces | 
 |  | Development of deep ocean basins | 
 |  | grazers (suspension-feeders) | 
 |  | scavangers (detritus feeders) | 
 |  | Ordovician/Silurian (Paleozoic fauna) | 
 |  | Diversity and Trophic levels | 
 |  | extinction of archeocyathids | 
 |  | Dominated by suspension feeders | 
 |  | planktonic filter-feeders (zooplankton) | 
 
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