(根据维基百科)[1],“所有已知类型的生物能够一定程度的对刺激的回应,繁殖,生长和发育和通过体内平衡自律。”Further, watching a video like the "[Earth Breathes as Seasons Change][2]" - superficially give the sense that "Earth is alive" so to speak. History of Earth might show that it is able to show "growth and development." Climate change, I would think shows Earth "responds to stimuli," and that it is able to "self-regulation" conditions to remain stable and relatively constant. Might even be possible to prove that given all life has a common source, and that source may have common from another planet, that "planets" are able to reproduce. All that said, seems hard, if not impossible to prove "Earth is alive." Why is this, and what observations if any, would lead to Earth being labeled an organism? [1]: http://en.wikipedia.org/wiki/Organism [2]: http://www.youtube.com/watch?v=kSNbLYHRrU8