Science Journalism Marches On

The claim that bacteria in the human body outnumber human cells by an order of magnitude or so has become a popular observation among Science Fans. A 2008 article in the ghastly New York Times states:

The bacterial cells also outnumber human cells by 10 to 1, meaning that if cells could vote, people would be a minority in their own body.

This is misleading. A single bacterium masses something on the order of 10-13 – 10-12 grams, while a human body cell is in the neighborhood of 10-9g — 1,000 to 10,000 times larger. By weight, bacteria therefore compose somewhere between 1% and 0.1% of you, depending mainly on how recently you went to the restroom. Thus, the Important and Popular Fact presented in the NYT and other sources is technically true*, in the sense that Vin Diesel is outnumbered by a small bag of crickets.

*: The claim also skips over the fact that the largest fraction of the bacterial population in question consists of symbiotes, which could be designated honorary human cells under the mitochondrial grandfather clause, but that’s a whole other post.

Author: strevdrrev

"Then go away!" said Zhuangzi, "and I will drag my tail in the mud."

10 thoughts on “Science Journalism Marches On”

  1. Very disappointed to see you endorsing weight-based electoral disenfranchisement like this, Rev. I mean, just wow. One cell, one vote.

    These irrelevant science “facts” are pretty common. Did you know that if humans could jump like grasshoppers do, we’d be able to leap over a football field? Also, if mass scaled linearly with length, there would be ants the size of continents.

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  2. Just noticed the article is by Nicholas Wade, who recently published “A Troublesome Inheritance”, which is moderately pro-HBD (think I read about it through Razib Khan, who said it was so-so), and based on its reception by progs definitely will not be one of Heather’s Picks.

    Score -1 for Wade’s epistemic credit score, I guess.

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    1. Also, “bacteria in the human microbiome collectively possess at least 100 times as many genes as the mere 20,000 or so in the human genome.” You mean, a whole ecosystem of many different species has more genes than a single organism? Gosh. And the number of genes means what again?

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      1. There is a certain generic template for the presentation of an Amazing Fact that is being used here. “Find two dissimilar things that are measured in the same units but differ by a few orders of magnitude, and present the difference as extremely significant”. In this case the motive seems to be to Impart A Sense Of Wonder to trivia-hungry NYT readers, sometimes it’s political nonsense.

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        1. “In this case the motive seems to be to Impart A Sense Of Wonder to trivia-hungry NYT readers” Science Fans, they ruin everything good.

          “What if the cash blown on a floating luxury showroom had been applied to San Francisco’s civic infrastructure?” What if they resorted to a barge because it’s fucking impossible to get anything built in San Francisco?

          But also that link needs to have a trigger warning: Salon.

          Also: when someone uses the term “affordable housing”, that’s a flag that they’re an idiot or a liar. The context here suggests liar–the key is the non-sequitur transition. “Imagine if instead of spending the money on a horse, they spent it on a Malaysian rubber plantation.” What the fuck? Oh, it’s a lying asshole talking.

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  3. The numbers are not important (as Simplicio has already noted), but the footnote is absolutely correct. You should reverse this post; put the mass in the footnote, but make the main point about how stupid it is to consider our gut flora and other symbiotes ‘not us’ when they are a necessary and integral part of us. Why, they are even heritable: not as heritable as our other cells or even our mitochondria, but then neither is culture; yet we consider a person’s memes to be as much a part of that person as their genes, and rightly so. The same goes for a person’s symbiotic bacteria.

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  4. “””The claim also skips over the fact that the largest fraction of the bacterial population in question consists of symbiotes, which could be designated honorary human cells under the mitochondrial grandfather clause, but that’s a whole other post.”””

    Please write that whole other post! The where/how/why of the symbiosis (or lack thereof) is the most interesting part.

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