Gastropods shed shells in single shot
Evolution doesn’t have to operate at a snail’s pace, even for snails. In experiments designed to simulate the evolutionary transition that produced slugs, researchers exposed baby snails to the metal platinum, causing the animals to develop without external shells. The research illustrates how a big leap on the evolutionary path of animal body plans might have occurred. It also reopens a can of worms concerning the development and evolution of an entire class of shelled creatures.
Scientists reared Marisa snails, best known for cleaning up algae and other debris in home aquariums, in petri dishes containing varying concentrations of platinum. At certain exposures, all of the roughly 80 percent of snails that survived were shell-less, Heinz Köhler of the University of Tübingen in Germany and his colleagues report in the September-October Evolution & Development. The researchers posit that the platinum is causing effects similar to the gene