Would you be willing to sacrifice YOUR life for a species, Rhythm?? I surely would NOT.
No one here is calling for the extinction of non-human species. Besides, with technology as it is- and as it is becoming- it would be possible to BRING BACK those species which would have gone extinct via cloning!
As I have stated before, I am perfectly willing to extinct all sorts of life to defend my daughter (my own life is rather less valued, as I am old and not long for this world anyway). However, I do not defend this willingness as some sort of moral imperative, or even a transcendant virtue -- it is pure selfishness, and may even result in the destruction of what I would be trying to save (to whit, my daughter). Yet, foolish human that I am, I would do so in an instant.
The difference between me and these others is that I know I am a fool, while they fantasize that they are not at least as foolish as I. Fools!

As for the extremis arguments, well, it is sometimes necessary to go to the extremes to get people to finally reject extremism and start talking sense. Do enviros hold extremist, indefensible positions? Of course! My position is that it is up to the real rationalists to reject both brands of extremism and to seek the middle path, where we can set the bar a little higher and perhaps find solutions that do not trade the future for the present.
RS