April 29, 2013 | David F. Coppedge

Secrets of Three Amazing Animals Unveiled

Here are accounts of three very different animals whose behaviors have baffled scientists till now.  Scientists are beginning to get at least partial answers for scientific mysteries by carefully observing and testing to see how things work.

Waving corals.  Some soft corals pulsate regularly.  Why is that?  Why would they perform motion that is energetically costly?  PhysOrg reported that scientists at Hebrew University of Jerusalem wanted to solve this “old scientific mystery.”

One of the most fascinating and spectacular sights in the coral reef of Eilat is the perpetual motion of the tentacles of a coral called Heteroxenia (Heteroxenia fuscescens). Heteroxenia is a soft coral from the family Xeniidae, which looks like a small bunch of flowers, settled in the reef walls and on rocky areas on the bottom of the reef. Each “flower” is actually a living polyp, the basic unit which comprises a coral colony. Apparently, the motion of these polyps, resembling flowers that are elegantly spreading out and closing up their petals, is unique in the animal kingdom.

Amazing FactsResearchers found that the corals take a “siesta” for a half hour every day.  They will also stop pulsing for a few minutes after being touched.  By measuring the water flow around the corals, the researchers found that the pulsations effectively stir the water around these filter feeders to enable new nutrient-rich water to flow in.  It also removes excess oxygen and brings in carbon dioxide, raising the rate of photosynthesis for symbiotic algae.  “The findings of this study indicate that pulsation motions are a highly efficient means for sweeping away water from the pulsating body, and for an increased mixing of dissolved matter between the body and the surrounding medium,” the report said.  The answer to this biological mystery was not just for curiosity: “These two processes (expulsion of medium and mixing of solutes) may lead to future applications in engineering and medicine.

Baby turtles:  Surely everyone who has watched TV footage of baby sea turtles scurrying across the sand toward the water thinks it’s cute.  Scientists agree, but ask questions beyond: how do the turtles travel so effectively, several body lengths per second, across soft sand?  Science Daily tells how researchers at Georgia Tech tried to mimic the action with “Flipper-Bot,” a robot with paddle-like limbs (see video of the turtles and the robot on YouTube).  A Georgia Tech biologist first filmed the hatchlings traveling toward a light at night.  Their clumsy-looking limbs are actually quite effective at scurrying over sand without moving it much.  They can control their wrists depending on the medium.  “On hard ground, their wrists locked in place, and they pivoted about a fixed arm,” the scientist explained. “On soft sand, they put their flippers into the sand and the wrist would bend as they moved forward.”  A robot model proved this is a good way to travel; it gives a high angle of attack, and reduces drag.  The article suggested that the new information “could ultimately provide clues to how turtles evolved to walk on land with appendages designed for swimming,” but one of the researchers quickly admitted, “We don’t have solid results on the evolutionary questions yet….”

Homing pigeons:  A mystery of bird navigation is closer to being solved.  PhysOrg reported that Viennese and Australian scientists have “added some important pieces” to the puzzle of how birds navigate, a skill that allows some species to span the globe on the wing.  It turns out every bird (but not humans) has little iron balls in sensory neurons.  “Remarkably, each cell has a single iron ball, and it’s in the same place in every cell,” they noted.  Even ostriches have them.  Perhaps these are the “elusive magnetoreceptors” that respond to the earth’s magnetic field.  A previous theory has been discredited.  It turns out that iron-rich clusters thought to exist in pigeon beaks were just blood cells.  If the iron in the sensory neurons is involved in birds’ magnetic sense, scientists still do not know how they work: “we’re a long way off understanding how magnetic sensing works,” one of the scientists said; “we still don’t know what these mysterious iron balls are doing.

The classical “scientific method” of observation, hypothesis, and testing can answer questions about “how things work” if they are amenable to repeated observation, as in these cases.  Stories about “how they got that way” by evolution are far less useful.  When scientists approach things as if they work for a purpose, whether coral pulsations or turtle flippers, they usually get two rewards: satisfying explanations that can bear repeated testing, and applications that can improve human life.  Liberate these scientists from the ball and chain of having to add a Darwinian just-so story to their work.

Speaking of birds, a great new film on bird flight is coming from Illustra Media.  Watch for the news here.  It contains a truly stunning story of migration, as well as other cutting-edge findings that were obtained by good observational scientific methods.  The film will illustrate a common experience in scientific research: when scientists look more closely at natural phenomena, they usually find answers that are far more dynamic and wonderful than previously thought: answers that transcend language and cause us to stand in awe.

 

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