William Hong wrote:

>Perhaps maybe you mean "divergent" evolution Frank?

It would be divergent evolution if they had a common ancestor, which they
do not.  Convergent evolution (to steal a taxonomist's term) is the process
whereby different species independently evolve similar traits as a result
of similar environments or selection pressures.  An obvious example, the
streamlined torpedo shape evolved for cutting through water has been
evolved by sharks and bony fish, by whales and dolphins (mammals), and by
the extinct sea-going reptiles (ichthyosaurs).  Apparently, there is an
optimum streamlined shape for gliding through water.  Animals from widely
divergent groups, with very diffrerent anatomies, have evolved amazing
convergencies.

In the case of the bass viol and the cello, each has reached its final
(?) evolution from a different ancestor and along distinct lineage.
The convergency is that both are bass bowed-string instruments slotting
optimally into a particular instrument niche- that of bass solo, continuo,
and ensemble performance.  They possess an optimal form for fulfilling this
role, despite their fundamental differences in construction (anatomy).  If
you ever have the opportunity to look inside each instrument you will be
quite amazed at the difference, though not as profound as that of a whale
v.  shark!

The cello, a member of the viola da braccio family and an overgrown violin,
evolved from the rebec.  The bass viol, a grown-up member of the viola da
gamba family, evolved from a fusion of the viheula and the lute.

>I would agree that the color of the viol is unique--not least from the
>fact that it's constructed so differently...

Precisely.  I often say to people the only thing they have in common is
their total length.  (Even the body/neck ratio is quite different)

>The viol makes for a wonderful continuo instrument, not least for its
>color, which makes up for any perceived lack of power or volume. It
>certainly didn't stop Bach from using them in his Sixth Brandenburg.

JS Bach composed outstanding obbligato parts for gamba in his Passions and
Cantatas, for which the cello affords no satisfactory substitute; brilliant
parts for two gambas in his Sixth B'Burg, where substituting cellos makes
too thick a texture; and three magnificent sonatas for gamba with obbligato
harpsichord, which all cellists pardonably play; but these sonatas have a
more brilliant sparkle and a finer balance on their own instruments.

>But I've yet to hear a cellist's rendition of the viol part in Marais'
>"Sonnerie de Ste Genevieve du Mont de Paris".  Does one exist?

Very likely.  Cellists have shown much interest in the extensive viol
repertoire.

Frank