Jahren introduces the Pontificia Universidade Católica do Rio Grande do Sul (PUCRS), a laboratory in Brazil that is documenting the many thousands of species of flora and fauna within the country’s borders. The PUCRS lab is particularly interested in recording and documenting freshwater fish, as these species are the “canary in the coal mine” (157). When fish species decline in freshwater habitats, it sounds alarm bells for all other related flora and fauna. What is increasingly disturbing in Brazil and around the rest of the Earth is the quick decline of species.

While extinction is a normal process—most species survive for about 10 million years before going extinct—the rate of extinction in the 20th and 21st centuries has greatly accelerated. Mass extinctions have occurred in the distant past, but they were rare events until now: “Based on the rate of decline and disappearance of species today we fear that we are currently on the verge of the sixth mass extinction” (159). The species under threat include both plants and animals. By 2050, the Earth may lose around 25% of its current species.