It is an astonishing circumstance that in spite of the advanced state of our knowledge in many domains of biological research, we still have not discovered perhaps 90 percent of the species of organisms on Earth. Further, of the 10 percent known, only a tiny fraction has been studied beyond a minimal diagnosis and bestowal of a Latinized binomial name.

It should be kept in mind that modern biology is organized into three dimensions. The first is the one most familiar to the public: a thorough account of a selected species across all levels of biological organization, from molecule to organism to ecosystem. Chosen for their immediate importance to humanity or, just as often, their suitability for solving basic scientific problems, these “model” organisms make up only a few dozen species, including the bacterium Escherichia coli for molecular genetics, the common squid for nerve transmission, the honeybee for social behavior, and humanity for everything.

The second dimension of biology is the diversity of life, arrayed in descending order from the ecosystems, such as ponds and forests, to the species of organisms that compose each ecosystem, and, at the lowest and most fundamental level, to the astronomically great diversity of genes that prescribe the distinguishing traits of the various species.

The third dimension is the tree of life, the history of all kinds of organisms, past and present, that have existed since the origin and early efflorescence of life on Earth over 3.5 billion years ago.

The second and third dimensions form the aforementioned neglected domain of biology. Until we get serious about exploring biological diversity, encompassing in particular the vast terra nova of microorganisms, fungi, and small invertebrates, science and humanity at large will be flying blind inside the biosphere. How can we fully understand the ecology of a pond or forest patch without knowledge of the thousands of species--indeed millions when bacteria are included--the principal channels of materials and energy flow? How can we anticipate and control the spread of new crop diseases and human diseases if we do not know what they might be, or the location of their endemic reservoirs, or the identity of the insect and other vectors that carry them? And, finally, and I mean finally in the literal sense, how can we save Earth’s life forms from extinction if we don’t even know what most of them are?

To explore life on a little known planet and to organize and make quickly accessible information as it pours in are the main tasks of the new biodiversity science. Considering its importance to everything we hold dear, including our own existence, it is striking that it is one of the most underfunded areas of science. Support given to develop biodiversity science will yield one of the most valuable benefits of all scientific enterprises.