Ordovician reefs were also home to large sea ... they collected food particles with feathery arms that waved in the ocean currents. The hard-bodied arthropods started eyeing opportunities on ...

However, in the Ordovician, the creatures were invertebrates, or organisms lacking a backbone, such as brachiopods, trilobites, and corals. These organisms were perfectly suited to survive in the warm ...

Researchers from Johns Hopkins University discovered that the mixing of sediments by worms and other invertebrates released ...