Is an organism more than the sum of its parts?

Dissociation: assembled and disconnected leaf tissues

I'm fascinated by organisms and their components. What does it mean to be a leaf, to be a plant, or to be human? As we strip away or observe the addition of new structures to a leaf, does it change its nature?                           Fern leaves were cleared, stained, and photographed at high magnification using a light microscope.