Scientists organize all of Earth's life forms into a hierarchy that begins with kingdom and works down into phylum, class, order, family, genus, and species. (To remember these categories, think "King Philip Crossed Over For Gold and Silver—a mnemonic referring to 16th-century Spanish exploration.) In this feature, step into the shoes of a taxonomist and classify three forms of life: a plant, an animal, and a...well, you'll need to figure that one out for yourself.