What's up with all those greenies??

Why is it that people care so much for the environment? Setting aside theories that predict the end of the world (ie global warming and climate change) what is it about the trees and animals that people care so much about? Whenever some big entrepreneur decides that he wants to build a casino in the middle of the forest or a resort on the coast there is more often than not an uproar of people that protest its development. But really, what do these people lose by the development of a resort in a remote location far away from where they live? If species X goes extinct how does this effect your life and your standard of living?

I ask this because in all honesty i AM one of these annoying greenies, but i don't know why?! No, im not just a greenie because the adds on tv told me that i should be and no i don't like the animals just because they can be all cute and cuddly, but when i hear about the affect on environment due to some kind of anthropogenic effect i still feel that it isn't right. When i hear that an animal might be going extinct i feel like the world has lost something. Why?? i mean it dosen't really change anything, if it helps us to advance as a race then is it a good thing? Aren't the greenies standing in the way of human progression?

All i know, is that every time i learn about the life that exists in our world i am always amazed by it and that i have a strong feeling that killing everything on it probably isn't a great idea. I mean if we did just look at everything in black an white then i would expect the world to be a pretty boring place and we all may as well just be robots.