Crinoids: our favorite echinoderms!

Crinoids: our favorite echinoderms!

Crinoids are sessile, filter-feeding benthic echinoderms restricted to marine environments.  They are the sister group to the other echinoderms, which include sea cucumbers, sea stars, and sea urchins.  Here is our current understanding of echinoderm evolution: There are many scientists working to untangle the evolutionary relationships between echinoderms, a great place to follow the progress … Continue reading

Vocab: Symbiosis–parasitism to mutualism

Symbiosis: “living together” (of unlike organisms) Symbioses can be classified based on the effect felt by the partners.  For instance, Parasitism: bad for the host; good for the symbiont Commensalism: neutral for the host; good for the symbiont Mutualism: good for both the host and the symbiont Typically, the larger of the partners is called … Continue reading

Vocab: Benthic and Pelagic

Animals that live associated with the bottom of the ocean are referred to as benthic.  Those that live associated with water away from the seafloor are referred to as pelagic.  The crinoid echinoderms and their associates discussed here are benthic. Many animals have both benthic and pelagic life stages–for instance, many benthic animals release their … Continue reading