>Anne Heise asks
>A math-teaching colleague of mine asked today why fruits tend to be
>round. We narrowed the question to why fleshy fruits are round and
>thought of some possible answers. But I told him I'd put the question
>out to you all and promised him there would be a wonderful diversity of
>answers from proximate to ultimate.
Anne,
Several responses come to mind.
First, by "round" does your colleague mean "spherical" or merely round in
the transverse (cross section) direction only? It seems to me that only a
minority of fruits are truly spherical, citrus fruits, tomatoes, and
cranberries come to mind.
Second, in terms of being round in cross section but not in longitudial
section, many fruits like bananas, peppers, gourds, pears, and okra fall in
this category. A good proximate reason for this is that the pistil from
which the fruits developed was round in cross section. I suspect that such
pistils (round in cross section) developed within flowers that were
actinomorphic (regular).
Of course, many fruits are not round in either longitudinal or
cross-section. Examples can be found in the bean family (legumes such as
snow pea), and the mustard family (e.g, the shepherd's purse, moneywort).
Interesting question; I'm sure the responses from others will be equally
interesting.
Kenneth M Klemow, Ph.D.
Department of Biology
Wilkes University
Wilkes-Barre, PA 18766
(717) 831-4758
kklemow at wilkes1.wilkes.eduhttp://wilkes1.wilkes.edu:80/~kklemow
