Ol’ PZ hit one on the head again in this post:
Do you even understand the argument? I’m not saying that we need to preserve the snail darter because it is a valuable organism in and of itself, but because we are screwing over ourselves when we smash and poison our environment to such a degree that as innocuous a creature as a small fish is unable to survive. I’m being greedy, not altruistic. It’s a position both sides ought to understand.
It hurts human beings when you put humans beings “first” and trample the environment. The human race depends on our god damn biosphere. How hard is that to understand? When the environment can’t support small, sensitive creatures, it is a canary in a coal mine. If you think the environment is an issue of the Left, you are part of the problem.