The idea was simple. We would culture the bacteria of people’s belly buttons to provide folks with a visual measure of the life on them, a reminder of the mysteries everywhere. Then we noticed something more serious. It might have been a good moment at which to turn back, but collectively our crew seems to lack that capacity so we stormed ahead, deeper into the squishy unknown.
We quickly found that peoples’ belly buttons differed in terms of which species live in them. They differed more than we expected. We were intrigued and so we decided to get a little more serious about our study. We teamed up with Noah Fierer (who I have still never actually met in person) to use molecular approaches to compile more complete lists of the species living in people’s belly buttons. This is when things got weirder. We expected that in employing this more complete method of sampling that the species in different belly buttons would become more similar from one belly button to the next (as we got a more complete sample of who was present in each). They got more different.
We began to more seriously wonder what explained the differences from one person to the next. We were finding hundreds and then thousands of species, many of which appear new to science. They included strange species, such as one species found on my body that appears to prefer to break down pesticides.
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See the study here.
The YourWildLife blog (Exploring the microdiversity that lives on us, in us and around us) is here.
LiveScience has a picture gallery of bacteria here.
A new study now suggests that bacteria may also have helped kick off one of the key events in evolution: the leap from one-celled organisms to many-celled organisms, a development that eventually led to all animals, including humans.
Published this month in the inaugural edition of the new online journal eLife, the study by University of California, Berkeley, and Harvard Medical School scientists involves choanoflagellates (aka “choanos”), the closest living relatives of animals. These microscopic, one-celled organisms sport a long tail or flagellum, tentacles for grabbing food and are members of the ocean’s plankton community. As our closest living relative, choanos offer critical insights into the biology of their last common ancestor with animals, a unicellular or colonial organism that lived and died over 650 million years ago.
“I would be surprised if bacteria did not influence animal origins, since most animals rely on signals from bacteria for some part of their biology,” King said. “The interaction between bacteria and choanos that we discovered is interesting for evolutionary reasons, for understanding how bacteria interact with other organisms in the oceans, and potentially for discovering mechanisms by which our commensal bacteria are signaling to us.”
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THE PROBLEM WITH environmentalists, Lynn Margulis used to say, is that they think conservation has something to do with biological reality. A researcher who specialized in cells and microorganisms, Margulis was one of the most important biologists in the last half century—she literally helped to reorder the tree of life, convincing her colleagues that it did not consist of two kingdoms (plants and animals), but five or even six (plants, animals, fungi, protists, and two types of bacteria).
Until Margulis’s death last year, she lived in my town, and I would bump into her on the street from time to time. She knew I was interested in ecology, and she liked to needle me. Hey, Charles, she would call out, are you still all worked up about protecting endangered species?
Margulis was no apologist for unthinking destruction. Still, she couldn’t help regarding conservationists’ preoccupation with the fate of birds, mammals, and plants as evidence of their ignorance about the greatest source of evolutionary creativity: the microworld of bacteria, fungi, and protists. More than 90 percent of the living matter on earth consists of microorganisms and viruses, she liked to point out. Heck, the number of bacterial cells in our body is ten times more than the number of human cells!
Bacteria and protists can do things undreamed of by clumsy mammals like us: form giant supercolonies, reproduce either asexually or by swapping genes with others, routinely incorporate DNA from entirely unrelated species, merge into symbiotic beings—the list is as endless as it is amazing. Microorganisms have changed the face of the earth, crumbling stone and even giving rise to the oxygen we breathe. Compared to this power and diversity, Margulis liked to tell me, pandas and polar bears were biological epiphenomena—interesting and fun, perhaps, but not actuallysignificant.
Does that apply to human beings, too? I once asked her, feeling like someone whining to Copernicus about why he couldn’t move the earth a little closer to the center of the universe. Aren’t we specialat all?
This was just chitchat on the street, so I didn’t write anything down. But as I recall it, she answered that Homo sapiens actually might be interesting—for a mammal, anyway. For one thing, she said, we’re unusually successful.
Seeing my face brighten, she added: Of course, the fate of every successful species is to wipe itself out.
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