Diversity (or, why whales should be saved)

Consider a simple ecosystem in balance (that some people may recognize from Ishmael by Daniel Quinn): lions, gazelle, and grass. The gazelle eat the grass, lions eat the gazelle, and the grass gains nutrients from the activity of both animals. It is easy enough to see that if, for example, there is a lot of rain and the grass becomes particularly rich and plentiful, the gazelle population will increase. As a result, the lion population will also increase with their food supply. Conversely, in a period of drought, both animal populations will decrease.

But now what happens in a period of severe drought (or freezing, or other catastrophe)? With no grass to eat, the gazelle population would vanish, followed by the lion population as well as the grass. Although this ecosystem was in equilibrium and could withstand minor perturbations, a significant shift in climate or other external forcings was sufficient to eliminate the system.

So, how does nature protect against this? Simple: lots of life, in all sorts of shapes, sizes, and environments. Death is not unnatural, nor is extinction. Nature (or Gaia, as some of us prefer for poetic reasons) does not act to preserve any particular species, but rather strives for the longevity of the community of life. Why save the whales? Because someday, whales may be the hope of this community.