Ashlee Lillis, an NC State Ph.D. candidate in marine sciences, wondered how the tiny oysters knew when to drop down and start looking for a home. Scientists know that larval oysters and other bivalves, like clams, respond to some chemical and physical signals in seawater, but Lillis wondered if the sound of the reef played a role. “When you’re as small as these larvae, even if you’re only 10 or 15 feet up in a water column you wouldn’t have any real sense of where you were in terms of the seafloor beneath you,” Lillis says. “But an ocean reef has very loud, distinct sounds associated with it. They’re noisy enough to be heard by scuba divers and snorkelers. Even though oysters don’t have ears and hear like we do, they might be able to sense the vibration from the sounds of the reef.” ...The team first made underwater sound recordings of oyster reefs and the open seafloor. Then they tested larval oysters in the wild and in the lab to determine if the settlement rates increased when they were exposed to reef sounds versus those from further out. The team found an increased settlement rate in both the lab and the wild when the larvae were exposed to reef sounds.Molluscs are extremely strong in the vision department; cephalopod eyes and visual processing systems are at least as good as mammalian. But they don't have anything like ears, and until now there's been no indication that they take any sort of auditory input. The fact that oyster larvae prefer a recording of the "right" sound to other recordings shows that they're not just picking up crude amplitude of vibration; they must be hearing in some fairly sophisticated way and processing the vibrations. Grand blueprint time! Genes determine goals, not structures. It's already clear that vision is one of the universal purposes; now hearing moves closer to universality.
Labels: Grand Blueprint
Polistra was named after the original townsite of Manhattan (the one in Kansas). When I was growing up in Manhattan, I spent a lot of time exploring by foot, bike, and car. I discovered the ruins of an old mill along Wildcat Creek, and decided (inaccurately) that it was the remains of the original site of Polistra. Accurate or not, I've always liked the name, with its echoes of Poland (an under-appreciated friend of freedom) and stars. ==== The title icon is explained here. ==== Switchover: This 2007 entry marks a sharp change in worldview from neocon to pure populist. ===== The long illustrated story of Polistra's Dream is a time-travel fable, attempting to answer the dangerous revision of New Deal history propagated by Amity Shlaes. The Dream has 8 episodes, linked in a chain from the first. This entry explains the Shlaes connection.