Cellular masonry (and intelligence?)

In 1878, agglutinated foraminifera were dubbed "nature's little masons" by A.M. Norman, a prominent British reverend and naturalist. William B. Carpenter, arguably the 19th-century's premier cell biologist, also pointed to the "skill" displayed by foraminifera in selecting materials to build their shells -- a characteristic that got Edward Heron-Allen in heated debates with colleagues over the definition of intelligence. (See, for example, his paper entitled Purpose and intelligence in the Foraminifera published in the Proceedings of the Zoological Society of London, 1914:1069-1070.) In future posts, I'll dedicate some space to Heron-Allen and examine the seemingly incongruous mix of science and mysticism that marked his career.

Four species of agglutinated foraminifera from the same handful of Antarctic sediment. Each species collects a characteristic range of grain sizes or type of mineral to build a shell.

Speaking of incongruous mixes, Claire Beynon's December 28th post juxtaposed a recipe for chicken kofta and my watercolor of Astrammina rara - one of the unicellular giants that we collect in Antarctica. About a decade ago, Joan Bernhard and I used straightforward statistical approaches to show that Astrammina "selects" sediment particles that range in size from 0.25 to 0.50 mm to use as the main non-compressible (read: hard) component of its shell. Since then, we and coworkers have noted that A. rara's shell usually contains a conspicuous, red-orange sand grain. This feature prompted ceramic artist Katherine Glenday to write a poem in which, to paraphrase, she describes A. rara as "the species that builds its heart on its house." I adore the beautiful aesthetic of that anthropomorphism! But it begs the question: does it really select one red grain, or is this simply a consequence of chance? If it is indeed displaying selectivity, what is the molecular basis of this cellular process?

As an expression of rote scientific curiosity, we'll do a bit of experimental work to explore this question and post some results here. In a sense, though, I almost don't want to know the answer. Why despoil a beautiful poem with a rational whitewash?