In fact, NO species is EVER in stable equilibrium (and if you do find one that way, it won’t be for very long). Environmental changes keep individuals constantly shifting strategies (those that can shift strategies) between reproduction/propagation of their genes in times of bounty and survival in times of shortage. (Obviously, these are the extremes of a gradient.)
Since individuals are shifting from “make babies” (or seeds) to “hold on to all resources and survive at all costs” and since populations are made up of individuals who will all be, more or less, subject to the same environmental conditions, you can expect that ALL populations will fluctuate in size around the carrying capacity of an area. (Note that the carrying capacity of an area actually changes as environmental changes occur.)
I have trivialized the factors that go into “environmental change”—these can be everything from increases in predation pressure, competition with other species for resources, bad weather, natural disasters, outbreaks of parasites, etc. Throughout all the ups and downs, there is always give and take among the members (species) of the community—not because they choose that to be the case, but rather as times and conditions change, so too does the species with the biggest advantage at any given time.
The fact that humans survived for more than 200,000 years WITHOUT destroying the world around them suggests that, at one time, we too lived by the rules of “limited competition” that Daniel describes in his books. The fact that we are now in the process of destroying every living thing on the planet to make room for our food or our food’s food (turning the biomass of the planet into human mass) means we are no longer playing by “the rules.” In Daniel’s words, we are no longer “living in the hands of the gods.”
NOTE: This question was answered by Dr. Alan Thornhill.
posted: 02 Jun 2001
updated: 02 Jun 2001