Carl Pike wrote:
>> I'm only a biochemist - but I don't see the connection of fruit shape to
> the fact that fruits are eaten by (and must be swallowed by) animals. Most
> animals I've observed are eating fruits not by swallowing them whole but by
> chewing them apart.
>> Carl S. Pike (717) 291-3958
> Department of Biology FAX (717) 399-4548
> Franklin and Marshall College Internet C_PIKE at ACAD.FANDM.EDU> P.O. Box 3003
> Lancaster, PA 17604-3003 USAThe answer may be a bit of both. Watch a squirrel eat an apple, and you
will see pieces fly, but watch a bird eat a pin cherry, and you get a
different perspective. Some fruit-eating animals do swallow whole
(explaining, in part, the colors and succulence of many fruits).
Spherical obviously goes down a tube gullet easier than cubic, winged, or
elongate. Some larger fruits may also be round because their
smaller-fruited congenerics are round. There is a limit to the amount of
flexibility in reproductive part shape and ovary development which may be
imposed as much by evolutionary history as seed-disperser physiognomy.
It is true that fruits are primarily a means for seed dispersal and much
can be learned by examining this correlation. It may also be true that
general fruit shape is a matter of taxonomic fixity. Also keep in mind
that the current seed dispersers, who may rip the fruit apart in the
process, may not be the primary seed disperser which was predominant
while the plant was evolving to its present form. That original
disperser may now be extinct. This seems to the case in South America
where there are many large-fruited plants but no comparably large
herbivores for dispersal. But, such herbivores were present during the
Pleistocene and earlier.
--
John R. Porter
porter at shrsys.hslc.org
