So Kallen over at the Biojournalism blog goes on a diatribe about great Echinoderms are, blah blah blah regeneration blah blah blah pentaradial symmetry. She then asks of her readers:
Tell me how snails are really cool, please?
OK, I'll tell you! Craig has already mentioned the coolness of the radula, how some snails can parasitize echinoderms, the backing of the Google Fight, and there huge range of sizes. He must have thought that was enough, maybe Kallen wasn't paying attention.
Mollusks also can harbor endosymbiotic bacteria that permit them to live in environments like hydrothermal vents. In particular, a snail that I study, forms dense beds around hydrothermal vent openings in the seafloor. This snail bed provides habitat for many other critters that wouldn't have been able to live there otherwise. So snails creating habitats, helping out others, being nice guys. Another Reason to love 'em!
This isn't even to mention the altruism of mussel, clams and oysters forming habitat for the "little guy". Now, have we settled this?
It's sometimes a trip looking back at old maps of Chesapeake Bay and Long Island Sound seeing the Oyster Reefs marked on them as "navigational hazards" since they were so large and close to the surface.
I don't recall any echinoderms which could filter up to 10L of water/gram tissue AND create highly complex 3D habitat, ecosystem engineering...shelter form currents for fish, enhanced survival of crabs in nearby burrows...