Our next step now is trying to understand how these microbial communities have systematically shifted in response to things like social complexity, new forms of agriculture, state-level societies. These are some of our interests. Unlike the Minoans and the Harappans, the city of Rome had to clean up after about a million people, so small, wood-covered gutters wouldn’t do. With 10 times more inhabitants than Knossos had at its height, and thus producing 10 times more waste, totaling 500 tons a day, the Romans had to construct a truly colossal sewer system. They built the Greatest Sewer, or Cloaca Massima, named after the Roman goddess Cloacina—the Cleanser, from the Latin verb cluo, meaning “to clean.” The Cloaca Massima moved millions of gallons of water and flushed about a million pounds of crap a day. It was so immense that Greek geographer and historian Strabo wrote that Roman sewers were big enough “for wagons loaded with hay to pass” and for “veritable rivers” to flow through them. Despite many earthquakes, floods, collapsed buildings, and other cataclysms, the Roman sewers stood strong over centuries. Toilets in the ancient city of Ephesus, located near the Aegean Sea in modern day Turkey. Getty KATHLEEN DAVIS: Speaking of dairy, food allergies and intolerances are pretty common these days. Can we learn about things like lactose intolerance from studying these fossilized feces and plaque?

We also were able to identify some of the dietary components. So, for example, from the individuals from northern Mexico, we recovered a lot of maize DNA and also some other DNA of plants that are very common in traditional rural diets. And so we were able to reconstruct some of that information.One song, "Are You Afraid", is an original composition that the band played live as an introduction to "Gravity" but never included on an official studio album. It foreshadows the gothic sound the band would adopt on their next album, Bloody Kisses. a b c Tortora, Gerard J.; Anagnostakos, Nicholas P. (1987). Principles of anatomy and physiology (Fifthed.). New York: Harper & Row, Publishers. p. 624. ISBN 978-0-06-350729-6. CHRISTINA WARINNER: Of course I do. So I work at both ends of the gastrointestinal tract. So I work on coprolites, which is paleo feces, and I also work on dental calculus, which is calcified dental plaque. So all the things that people spend money trying to get rid of I’m so interested in. And I definitely have favorites. There’s some that we’ve found that we’ve just found really fascinating information from.

Darlin, Damon (7 March 2015), "America Needs its own Emojis", The New York Times, archived from the original on 30 October 2016 , retrieved 1 March 2017 And yet, they don’t have any of these mutations that are associated with producing lactase. So this has long been a puzzle that these mutations don’t actually explain all of the dairying behavior that we see in populations around the world. So we’ve been working really closely with herders in Mongolia trying to understand this. And we are starting to gather evidence that we think that the microbiome is really strongly involved in this process. CHRISTINA WARINNER: Yeah, so coprolites are fantastic in terms of the range of information you can get from them, but they’re rare. So we can only really access particular places and times in the past. What’s really exciting about looking at calcified dental plaque, or calculus, is that nearly every skeleton has it. And so this really opens up the entire archaeological record for us to investigate the past. Feces is the scientific terminology, while the term stool is also commonly used in medical contexts. [29] Outside of scientific contexts, these terms are less common, with the most common layman's term being poop or poo. The term shit is also in common use, although it is widely considered vulgar or offensive. There are many other terms, see below.

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We have various terms for excrement, polite and impolite, one of them being “waste,” from a root meaning “empty” or “desolate.” In fact the strong smell of animal excrement signals its richness in diverse carbon and sulfur and nitrogen molecules, and so its value as nourishment for other living things. When early farmers discovered that value thousands of years ago, they made possible the long-term success of agriculture, and with it the development of civilization. KATHLEEN DAVIS: These ancient poops are called coprolites. And they’re pretty rare. The origins might be less than glamorous, but each one is a gold mine of information about who left it behind. And that’s because coprolites are a snapshot of the microbiome from which they came. Some researchers say studying these ancient records of diet and bacteria that helped us learn about modern problems like lactose intolerance and inflammation.

Ghassemi KA, Jensen DM. Lower GI bleeding: epidemiology and management. Curr Gastroenterol Rep. 2013;15(7):333. doi:10.1007/s11894-013-0333-5Many water-based sewage systems we use today continuously over-enrich waterways, contributing to toxic algal blooms and coastal marshes’ decay. Rao SS, Lee YY. Approach to the patient with gas and bloating. In: Podolsky DK, Camilleri M, Fitz JG, Kalloo AN, Shanahan F, Wang TC, eds. Yamada's Textbook of Gastroenterology. John Wiley & Sons, Ltd; 2015:723-34. doi:10.1002/9781118512074.ch40 And in many ways, these changes are associated with health consequences and chronic inflammation. So the big question we wanted to ask was, historically or pre-historically, when did these changes start to happen? Is it really associated with industrialization? Or might it begin earlier with more intensive agriculture, or maybe with the beginnings of agriculture? CHRISTINA WARINNER: So the microbiome is this community of bacteria that lives in and on the human body. And they’re very important. For a long time, they were very difficult to study. And so we really underestimated their importance. But we now realize they’re a fundamental part of our biology. And we actually rely on many of their activities for basic biological functions. Everything ranging from digestion to even producing some of the vitamins that we require.