Dylan, I think it is dangerous to hold beliefs just because they suit our conservation strategies, or because they make us feel good. We should try to believe things because they are true. I think the evolutionary picture, which is well-enough supported that we think it is true, provides a very powerful motivation to save biodiversity. Under this view, plants and non-human animals have just as much a right to exist as we do. In this view, humans are not the endpoint of creation, and animals and plants are not merely our servants, not merely made for our entertainment. On the contrary we now know that we are animals just like them, they are complex beings not qualitatively different from us, we are kin to all of them, and we are riding this ship together. Who would not feel guilty for snuffing out the last member of a species, knowing that it took millions of years to evolve, and that it would now, by an act of arrogance, disappear from the universe forever? Lou