It is easy to think today that we know most of what there is to know about life on Earth. But most living things have yet to be discovered or named, much less studied. We are surrounded by our own ignorance. This is even true in the wilderness of our indoor spaces — our homes, schools, offices and other enclosed places. These, too, are terra incognita. But we can be the Darwins of our own basements, attics, bedrooms, kitchens and bathrooms. What we find is likely to surprise us.
The study of the life indoors began in earnest with the work of Antonie van Leeuwenhoek (1632-1723), a Dutch microscopist. Leeuwenhoek studied the life around him in his home and town with an obsessive sense of wonder. But over time, the observation of life indoors came to focus on dangers, like deadly microbial pathogens or their insect vectors, and how to kill them, while the search for new or unstudied species focused on old-growth forests, remote islands and deep seas. Only in the last decade or so have scientists begun to seriously document life indoors, revealing marvel after marvel.
In one study I was involved in a few years ago, we sought to find all of the arthropod species (insects, spiders and their kin) in 50 houses in Raleigh, N.C. We expected to find a few dozen species. We found more than a thousand. In another study of 1,000 homes across the United States, we found tens of thousands of bacteria species, most of them unstudied, many new to science. Inside those homes we discovered more kinds of fungi than there were named fungal species in North America. Each time we study homes what we most clearly find is how little we know about what is hidden in our midst.