Welcome back. The "spark of life".
The "spark of life" is clearly the same in all beings. And DNA, at the root of it, rules. As Stephen Jay Gould pointed out, when the lion kills the antelope, lion DNA wins. When the antelope gets away, antelope DNA wins. Either way is irrelevant to DNA, it wins.
History has shown a continuous shift from a Man-centered, Earth centered Universe to one in which Man has a relatively unimportant role. I believe that trend will continue, especially as life is discovered in other parts of the Universe. One day only the very superstituous will see a qualitive difference between the essence of Man and other animals.
Some Buddhists mark a difference between "sentient" and other beings, though, which excludes plants (as far as we can tell).
Arf