cycl
beginner’s corner
by
Ba
rba
ra Shaw
PLANT SEX:
DIOECIOUS AND MONOECIOUS
REPRODUCTION
Genetic exchanges have been going
on since bacteria ruled the earth. In
time, special structures developed
to get genes from one individual
to the next. It turns out good sex is
extremely important to the fitness of
a species to thrive in its environment,
and thus to the fate of all life.
88
grow cycle
L
ife evolved in the oceans and stayed there—
nothing bigger than a bacterium—for a
couple of billion years. Slowly, life developed
complex metabolic pathways, cellular anatomy,
and organelles such as nuclei that would even-
tually allow production of large specialized
cells. Ages later, cells banded together into
multicellular forms and, by half a billion years
ago, produced individuals with billions of cells
and separate lives. Sex could no longer occur
simply by tickling a nearby cell.