September 13, 2008 | David F. Coppedge

Sea: the Light

Some of the most abundant unicellular organisms in the ocean are diatoms.  Physicists are eagerly studying the optics of their pill-box-like shells, because they can manipulate light in surprising ways.  Imitation of diatom light tricks may lead to biosynthetic devices like improved drug delivery systems and solar cells, an article on the BBC News said.
    The “intricate designs of their silica shell walls” are not just geometrically pleasing (03/19/2002) and strong (02/19/2003) and artistically awesome (07/21/2004).  Scientists have found that they strongly diffract light.  Their optical qualities may work to spread the light evenly throughout the cell bodies of these organisms whose light-harvesting chloroplasts depend on light.  Maybe this accounts for the particular patterns on species of diatoms that come in “all shapes and sizes” and inhabit almost every body of water on the planet.
    The article speculated about the evolution of diatoms.  “Why have diatoms evolved these nanostructures?” reporter Elisabeth Mitchell asked.  The even diffusion of light seemed to offer a satisfactory explanation for her.  She added one line, though, that wins Stupid Evolution Quote of the Week:Nature started to evolve complex colour and light manipulating systems during the Cambrian explosion – about 500 million years ago.”
    Moving right along, Current Biology1 mentioned another creature with a remarkable ability to respond to light – in this case, moonlight.  The creature is the Palolo worm of the South Pacific.  Foster and Roenneberg were talking about lunar effects on biological behavior when they said,

One well known example will suffice to illustrate lunar related rhythms in the animal world.  The Palolo worm (Eunice viridis) is found on several coral islands near to Samoa and the Fiji Islands.  The palolos reproduce by swarming during the last quarter of the moon in October and November.  The terminal parts of their bodies drop off and float over the surface of the water, releasing sperm and eggs.  The natives of the Samoan Islands have known this for centuries and predict the date and time of day when the emergence occurs so that they can be ready to catch the worms for food.  Studies have attempted to determine whether it is the direct effect of lunar illuminance which stimulates swarming.  This seems unlikely because cloudy or clear whether [sic] conditions have no effect on the spawning date.  Furthermore, the Palolo worm lives at depths of 3-5 metres within coral rocks, where moonlight would not easily penetrate.  Studies in an allied species of polychaete worm have demonstrated that moon-related rhythms in behaviour continue in isolation from any environmental influence.  Collectively the data suggest that the Palolo worm and other polychaete worms have an endogenous circa-lunar timer.

In other words, these sea worms don’t need to see the moon to know when it’s up.  They can tell when it is just the right hour of the right month of the right time of the year to come up and spawn.  As for what kind of accurate lunar calendar it uses, and how it arose, they didn’t say.  Another paper by Wilcockson and Zhang in Current Biology2 discussed sea creatures that adjust their biological rhythms to the tides: “crustacea, annelids, molluscs, fish and even a few insects.”  As to how that kind of timekeeping evolved in such a diverse array of creatures, they could only speculate, “Moreover, marine animals pre-date their terrestrial relatives and the question arises as to whether circadian clocks could have originally evolved from tidal oscillators?
    Speaking of the moon, do we exhibit lunar rhythms?  Foster and Roenneberg denied that the moon affects human behavior.  They discounted all the urban legends about human “lunacy” and said, “there is no convincing evidence that the moon can affect the biology of our own species…. the moon appears to have no effect upon our physiology.”  As evidence, they provided a table of studies that disprove all alleged effects of the moon on human behavior and biology, despite the ongoing strong beliefs of many people to the contrary.  “If an individual expects certain behaviours to occur with the full moon,” they said, “then selective recall and/or selective perception will reinforce this view.”  Humans are strongly responsive, though, to the 24-hour day – as any jet-lagged businessman can attest.  How that evolved, they could only speculate.


1.  Foster and Roenneberg, “Human Responses to the Geophysical Daily, Annual and Lunar Cycles,” Current Biology, Volume 18, Issue 17, 9 September 2008, Pages R784-R794, doi:10.1016/j.cub.2008.07.003.
2.  Wilcockson and Zhang, “Circatidal Clocks,” Current Biology, Volume 18, Issue 17, 9 September 2008, Pages R753-R755, doi:10.1016/j.cub.2008.06.041.

Human biology can be affected by the moon by intelligent design.  Didn’t Foster and Roenneberg realize that the Jews were commanded to the blow the ram’s horn each new moon?  Doesn’t the sight of a full moon generate design and purpose to sit by the lake on a date?  Isn’t the phenomenon of a lunar or solar eclipse a cause for intelligent humans to purposefully go outside and view the awesome sight?  Only when thinking of humans as biological robots can a scientist say there is no influence.  A mind with choice can do what genes alone cannot.
    Human minds can also investigate nature and appreciate the design in creatures that exhibit optical perfection and accurate timekeeping.  One might notice that diatoms and worms are among the simplest of organisms (but see 10/01/2004), lacking the brain power to plan, design and execute the systems embedded within them.  It is sad that some observers believe in implausible miracles.  There are plausible miracles, you see.  One that is implausible is that optical perfection sprung into existence in a Cambrian explosion.

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