> Continents are geological structures, and no, size does NOT count.

Thanks, Andrew G, but of course a snail or flower wouldn't know a tectonic
plate if it hit them. Biologically, a continent can be considered, at least
for purposes of argument, as a large, contiguous body of land. I suppose one
can dispute whether Africa is part of Eurasia, and whether the Americas
constitute a single continent. Biologically, the isthmuses (isthmi?) of
Sinai and Panama do not allow all sorts of plants and animals to move from
one body of land to the other, so one can well argue that North and South
America are separate continents. It's hard to argue that Europe is a
separate continent from Asia however.

Biological provinces, now, that's another issue! India is separated from the
rest of the world by seas, mountains and deserts on most sides, being open
to similar environments only on the eastern side. One would expect land
snails and freshwater mollusks to diffuse relatively easily from the wet
parts of India to Burma and southeast Asia generally, but not to Iran or
China.

Andrew K. Rindsberg
Geological Survey of Alabama