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> Not sure what you mean by "completely genetic". What cause other than
> genetic would "handedness" be due to?
Certain left and right handed planktonic forams correspond very well to water temperature and thus provide a good marker, e.g., for glacial versus interglacial intervals in the geologic record. (Mollusks also provide good indicators, but in different contexts-it's easier to spot Arctica islandica than forams in an outcrop, but harder to get a good specimen of Arctica out of oil well cuttings.) This has been thought of as a temperature-controlled intraspecific variation, but recently has been suggested to be different, albeit similar, species with different temperature preferences.
Dr. David Campbell
Old Seashells
University of Alabama
Biodiversity & Systematics
Dept. Biological Sciences
Box 870345
Tuscaloosa, AL 35487-0345 USA
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That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droitgate Spa
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