[A] new field called experimental evolution is showing us that
sometimes evolution occurs before our eyes, with rapid adaptations
happening in 100, 50, or even a dozen or fewer generations. Depending on
the life span of the organism, that could mean less than a year, or
perhaps a quarter-century. It is most easily demonstrated in the
laboratory, but increasingly, now that we know what to look for, we are
seeing it in the wild. And although humans are evolving all the time, it
is often easier to see the process in other kinds of organisms.
Humans are not the only species whose environment has changed
dramatically over the last few hundred years, or even the last few
decades. Some of the work my students and I have been doing on crickets
found in the Hawaiian islands and in the rest of the Pacific shows that a
completely new trait, a wing mutation that renders males silent, spread
in just five years, fewer than 20 generations. It is the equivalent of
humans' becoming involuntarily mute during the time between the
publication of the Gutenberg Bible and On the Origin of Species. This
and similar research on animals is shedding light on which traits are
likely to evolve quickly and under what circumstances, because we can
test our ideas in real time under controlled conditions.
Most social scientists' reaction to genetic explanations for human variation remains a strange combination of wishful thinking and neurotic feeling. Open your minds, my brothers and sisters.