The advent of DNA technology has radically changed how scientists perceive the evolutionary relationships of the plants and animals on our planet. Species thought to be closely related turn out to be distant relatives, and vice versa. These new discoveries have demolished the old-fashioned edifice of taxonomical hierarchy, which conveniently placed each species in a genus, each genus in a family, and so on. This hierarchy was a useful way to organize field guides and reference works. Nowadays, authors are loath to organize their texts in this manner—doing so, they fear, implies that they are oblivious to the paradigm shift that has occurred in their field. But science has yet to settle on a new set of conventions for organizing taxonomical information in text, and the result is that many manuscripts are coming to publishers in a primordial muddle.
Science authors, don’t abandon the use of taxonomical hierarchy in your texts just yet. It remains a useful tool for readers’ navigation of your books. The taxo hierarchy readily converts into a typographical hierarchy, which is what allows readers to keep track of their position in your material. All books contain such arbitrary schemes: a memoirist narrates her life in chapters, but her experiences weren’t so tidily organized. Remember that your primary purpose in writing a book is to communicate effectively, not to mirror the messy complexity of life.