The challenges of seeing the profusion of tiny life

When I imagine life on Earth, I think of grand images: springboks bouncing across the African savanna, penguins waddling in the snow, dolphins leaping into the air, redwood trees soaring above the forest. But scientists are exploring a profusion of creatures with equally fascinating behavior that aren’t seen in David Attenborough–style documentaries. In fact, our eyes can’t see them at all.

Minuscule life-forms known as protists have been known for centuries. But powerful microscopes, advances in genetic and computational technologies, and old-fashioned fieldwork are now revealing extensive diversity among these single-celled life-forms. Many are bizarre enough to star in a science fiction series. As life sciences writer Susan Milius reports, one critter has a “head” that spins, a skill creepy enough that its discoverers gave it the name Daimonympha friedkini, inspired by the demonically possessed child in the 1973 film The Exorcist and its director, William Friedkin. Another creature, shaped like a flying saucer, glides into the bodies of its prey, devouring them from the inside.

These two discoveries and many other recent ones are forcing scientists to rethink their concepts of how microbes are related to other organisms, as well as to rethink the whole tree of life. “What struck me most as I worked on the story was how little of it I can see,” Milius said of the tree of life and its many microbial branches. That and the fact that it’s not so much a tree as invisible bramble tangles of life, Milius says.

Trying to figure out how to illustrate the protists in the bramble tangles proved a challenge. Science News design director Tracee Tibbitts spent many hours digging through electron microscope images in search of the right tiny, crazy-looking things. “Species ID is a recurring theme at Science News,” Tibbitts told me. “This took it to another level.”

And even when she found the right species, the images often didn’t capture what makes these creatures special; their physiology is so alien to ours that they all tend to look alike. We wondered if drawings might work better. Many historical depictions of long-known protists were penned by Ernst Haeckel, a supporter of the discredited “science” of eugenics, and used as design motifs by René Binet, a Trotskyite turned Nazi. We felt uncomfortable giving those people more attention. So back to the hunt for other options.

Ultimately, we were able to find images that we think do these creatures justice, revealing their remarkable forms and behavior, like that spinning demon “head.”

The experience has left us marveling at the diversity of life, not only these tiny life-forms but also much larger creatures featured in this issue, including a parasitic worm that made a home for itself in a woman’s brain, pirate spiders that trick their prey into walking the plank, songbirds that are excellent problem-solvers and small snakes that take supersize gulps.

There’s so much more to discover about Earth’s inhabitants, the majority of which dwell in the microbial world. The tree of life is vast, and the part that looks like us is incredibly small.

Nancy Shute is editor in chief of Science News Media Group. Previously, she was an editor at NPR and US News & World Report, and a contributor to National Geographic and Scientific American. She is a past president of the National Association of Science Writers.