Everywhere we look, new life emerges. Bats the size of bumblebees. A roundworm that feasts on bacteria more than a kilometer underground. Even microbes that fill the air and cause rain or snow.
Scientists want to know how many species we share the planet with—especially since we're killing them off at least 100 times faster than at any period in recent geologic history.
The latest census effort guesstimates roughly 8.7 million species on Earth and notes that we know only 1.2 million of them. It’s published in the journal Public Library of Science Biology.
This effort may merely illustrate our ignorance, as the researchers extrapolated from what taxonomists have logged to date. The only real answer is the long, hard slog of searching for life everywhere and recording it when we find it. The "bar code of life" project is one such initiative, using genetics.
Even then, the tiniest life forms may remain massively undercounted. After all, there can be thousands of different microbes in a single spoonful of earth or sea. Pity the poor nematode that may vanish from the record of life before we even know it.
[The above text is a transcript of this podcast.]