Fighting Mother Nature with Biotechnology - The Oxford Topic of Food, Politics, and Society - page 432

resources became limiting and the population leveled off at the 1:1 replacement ratio.
Another example of divergence is in ordinary ecological successions, such as seen along
the shoreline of an aging lake, where a sequence of successive species invades, expands
to dominate the area, and then gradually dies of, giving way to the next order of species
until eventually the area that was once lake becomes forest. But again, over the period
of several generations, the number of individuals of any given species in the planetary
ecosystem remains remarkably stable.
Species have been identified with a long-term replacement ratio below 1:1 (i.e., all spe-
cies that are now extinct) and many with fluctuations around the 1:1 ratio. But no spe-
cies has sustained a long-term ratio above replacement, so we're not sure how Mother
Nature will punish such impudence. But we're about to find out. One arrogant species
has been increasing at above replacement ratio for many generations. If left unchecked,
that presumptuous species will ultimately cover the planet, thus destroying itself and
everything else still here. That species is, of course, Homo sapiens .
Humans as Unnatural Species
Ordinarily, Mother Nature restricts population growth of any species by any of sev-
eral limiting factors, such as food availability, predators and diseases (e.g., myxo-
matosis in rabbits, bubonic plague in humans), famine, and pestilence and other
plagues. But human ingenuity and technology has effectively overcome many of
these strictures. Modern humans rarely succumb to large-scale famine, to preda-
tors, or to tuberculosis, diphtheria, smallpox, measles, malaria, or even cancer
(curiously, wars and other human conflicts do not effectively reduce long-term
human population growth as the victims are primarily males. In human reproduc-
tive biology, males are readily substituted, with one fecund (lucky?) male able to
compensate for many males lost in battle. If, instead, young females were the pri-
mary casualties of war, human populations would suffer much more. And in any
case, war is a human construct, not a “natural” population control mechanism). So
far, we are the only species to maintain a reproductive replacement ratio above 1:1
for a substantial number of generations.
Mother Nature also uses physical and geographical measures to limit species dis-
tribution. The natural niche for humans is tropical and temperate subtropical parts
of the globe in nondesert areas where water and nutriments are plentiful. But human
ingenuity has overcome these conditions, too, with innovations ranging from warm
clothing (starting with animal furs involuntarily donated by other creatures of Mother
Nature) and central heating (starting with fire, one of the first technologies adapted by
human ingenuity to serve humanity) that allow us to live in cold climates. Irrigation,
a human innovation to divert the natural flow of water, and agriculture, a human arti-
fice to replace those natural species inhabiting a given plot of land with those few spe-
cies important as foodstocks for humans, allowed us to thrive in arid and barren areas.