kottke.org posts about biology
The Valdivia Expedition, led by German marine biologist Carl Chun in 1898-1899, was the first time humans had explored the ocean depths below 500 fathoms. What they found changed our conception of the oceans. The results, in the form of 24 volumes of text and illustrations, took decades to be published. Among the volumes was The Cephalopoda, published in 1910 and filled with colorful hand-illustrated drawings of octopuses and squid, courtesy of the Biodiversity Heritage Library.
I found this on Brain Pickings, which identifies the illustrator as Friedrich Wilhelm Winter, a credit I couldn’t find in the actual book itself. They’re also selling some of the illustrations as prints, like this one of the octopus featured above.
Darwin’s theory was of its time, born in “the heyday of classical liberalism, dominated by thinkers like Adam Smith, David Hume, and Thomas Malthus, who valorized an unregulated market.” And so, in itself and in multiple interpretations of the work through the years, was seen through a lens of competition. “Survival of the fittest” has become shorthand for his work and used time and again to “prove” the value of competition in evolution and in day to day human endeavours. But what if collaboration actually occupies a much more prevalent place?
Similarly, collectively owned spaces or institutions (like communal land trusts or co-ops) are often presumed short-lived or inefficient, doomed to suffer the “tragedy of the commons” as the innate self-interest of each member leads to an overuse of collective resources—a thesis that has been debunked again and again since its first articulation by Garrett Hardin in 1968. To put it simply, we have let Darwinism set the horizon of possibility for human behavior. Competition has become a supposed basic feature of all life, something immutable, universal, natural.
There have been numerous research projects in various fields trying to get us away from that focus on competition, notably biologist Lynn Margulis’s paper in 1967:
Rather than competition, it was collaboration, she argued, that constituted the origins of eukaryotic cells, which is to say, all complex life on planet Earth. Though her paper was rejected by as many as 10 journals before it was published in the Journal of Theoretical Biology, Margulis’ endosymbiont theory for the origin of eukaryotic cells is now the scientific consensus.
Since then, again and again, microbial species have shown us collaboration and interdependence in multiple settings, including our own digestive tract.
The National Institutes of Health recently found that over 10,000 microbial species occupy what they call “the human ecosystem,” outnumbering human cells 10 to 1 and doing diverse kinds of work at almost every level of the body’s processes. Bacteria, for instance, may make as much as 95 percent of the serotonin in our bloodstreams, meaning you have a diverse symbiont community to thank for your pleasant mood.
We can also look at mycorrhizal fungi, which collaborates with trees and various other plants in ways we are just starting to understand, like shown in the work of ecologist Suzanne Simard.
These are just some examples of a resurgence of understanding for collaboration in nature, instead of relying on our human focus on competition.
Darwin’s legacy aside, though, one critical takeaway from all this is that we must learn to recognize the impulse to naturalize a given human behavior as a political maneuver. Competition is not natural, or at least not more so than collaboration.
MIT Technology Review’s Antonio Regalado reports on an improved gene editing technique that can rewrite DNA without actually cutting the DNA (which can damage and introduce errors into the genome). It’s called “prime editing”.
Today, in the latest — and possibly most important — of recent improvements to CRISPR technology, Liu is introducing “prime editing,” a molecular gadget he says can rewrite any type of genetic error without actually severing the DNA strand, as CRISPR does.
The new technology uses an engineered protein that, according to a report by Liu and 10 others today in the journal Nature, can transform any single DNA letter into any other, as well as add or delete longer stretches. In fact, Liu claims it’s capable of repairing nearly any of the 75,000 known mutations that cause inherited disease in humans.
From the abstract of the report:
Prime editing substantially expands the scope and capabilities of genome editing, and in principle could correct about 89% of known pathogenic human genetic variants.
See more coverage of this story at Nature, Scientific American, and Wired.
Ants are fascinating. They’re small and individually dumb, but together they can form very complex societies capable of activities like farming and altering entire ecosystems. In this video, Kurzgesagt shows how the Argentine ant became one of the most numerous and successful species of ant in the world, forming a single mega-colony across the entire Earth, from Argentina to the US to Japan.
“The enormous extent of this population is paralleled only by human society,” the researchers write in the journal Insect Sociaux, in which they report their findings.
However, the irony is that it is us who likely created the ant mega-colony by initially transporting the insects around the world, and by continually introducing ants from the three continents to each other, ensuring the mega-colony continues to mingle.
“Humans created this great non-aggressive ant population,” the researchers write.
Curious about the social behaviors of cephalopods, marine biologist David Scheel brought an octopus named Heidi home to live with him and his teenaged daughter. In this clip from an upcoming PBS show called Octopus: Making Contact, you can see the octopus changing colors while colors while she sleeps, which Scheel speculates is due to actions happening in the octopus’s dream.
If she is dreaming, this is a dramatic moment. You can almost just narrate the body changes and narrate the dream. So here she’s asleep and she sees a crab and her color starts to change a little bit. Then she turns all dark; octopuses will do that when they leave the bottom. This is a camouflage, like she’s just subdued a crab and now she’s going to sit there and eat it, and she doesn’t want anyone to notice her.
This program already aired in the UK with the much snappier title of The Octopus in My House; check out a review here.
Heidi loves to play. Given a toy (an old pill bottle, say), she hurls it round as if it were a swimming aid, and she a toddler newly out of water wings. Scheel has trained her so effectively to pull on a string that activates a buzzer that in the end he has to dismantle the thing if he wants to get a night’s sleep. She loves to touch and be touched, entwining her arms with those of Laurel for minutes at a time. Does she recognise her owners? Indubitably. When Scheel approaches the tank as himself, she rushes to its side, as if in greeting. But when he approaches disguised in a rubber mask, she hides.
(thx, dunstan)
The YouTube channel Primer is running a series on evolution and how it works. Topics include mutations, selfish genes, and altruism in natural selection. The most popular video of the series is this one on the simulation of natural selection:
In it, you can see how different environments cause groups to tend towards certain traits (size, speed, sensing ability) based on food availability, with random mutation and reproduction in the mix as well. Seeing the populations’ traits change in realtime as the generations pass is a powerful way to make sense of a complex concept.
Biology is one field I don’t know supremely well, having had a couple of college courses and then mostly just public television documentaries. So it’s always cool to get a new concept or two to play with, like the Hayflick Limit.
What is it?
In normal, replicating cells, all the important genetic code in a cell’s nucleus is protected by telomeres—sections of non-coding DNA on the ends of chromosomes. (Elizabeth Blackburn, who won a Nobel for her work on telomeres, compares them to the caps on the end of shoelaces that keep them from fraying.) Every time cells divide, telomeres shorten ever so slightly; the white blood cells in newborn humans have telomeres that consist of about 8,000 base pairs, which falls to around 1,500 in the elderly.
The Hayflick limit is thought to occur when telomeres are gone and cell division would be risky, because without their protection, loss of genetic information would occur. When cells no longer replicate, they’re considered “senescent”: they carry on most of their normal cellular activity and eventually die. The Hayflick limit is one cause, but external stress, like an infection, physical trauma, or UV radiation can hasten cell death, according to Jan van Deursen, a cancer biologist at the Mayo Clinic in Rochester, Minnesota.
Senescent cells are a culprit in aging, but they also have benefits. They give off proteins that can recruit immune cells, which can promote wound healing, and they’re one of our body’s defenses against cancer. One of the reasons cancer occurs is when cells switch on a gene that allows them to rebuild their telomeres—kind of like speeding through a stop sign. That’s why the only immortal human cells are cancer cells.
So the Hayflick Limit, if it could be waived, could theoretically prevent or delay aging. But as it is, it’s a built-in cap on how many replications a body’s cells and tissues can undergo, so it guarantees our mortality.
Here’s what Hayflick himself had to say about it:
To slow, or even arrest, the aging process in humans is fraught with serious problems in the relationships of humans to each other and to all of our institutions. By allowing asocial people, tyrants, dictators, mass murderers, and people who cause wars to have their longevity increased should be undesirable. Yet, that would be one outcome of being able to tamper with the aging process.
I guess at a minimum, as bad as everyone is, at least they (as an individual) are not around to be bad forever? I’ll take that silver lining.
Gizmodo’s Daniel Kolitz recently asked a panel of anatomists and evolutionary biologists about what the most useless part of the human body might be. Biology professor Dr. Nathan Lents reminds us that our bodies contain ample evidence of our design by evolution:
It’s hard to pick just one! The human wrist is a clunky hodgepodge of unnecessary bones. If we could design that joint from scratch, there is no way we would stick eight small, fixed, and mostly useless bones in there. We also have the stump of a tail that we could totally do without. It does nothing for us except occasionally gets injured or develops cancer.
I think my favorite useless body part is the pyramidalis muscle, which is located in our pelvic floor and attaches to the pelvis and some other connective tissue in our nether regions. What does it do? Well, when you flex this muscle, you can sort of squish the tissue in that area around pointlessly, but in monkeys and other mammals, it helps to manipulate the tail. So useless is this muscle that at least 20% of us don’t even have one and we don’t even miss it. I always enjoy telling people that, although humans and other apes don’t have tails, we still have the muscles to flex them!
In this time lapse filmed by Jan van IJken, the embryo of a salamander is shown transforming into a hatched tadpole, from a single cell to a complex organism in a three-week process that’s condensed into just six minutes of video.
The first stages of embryonic development are roughly the same for all animals, including humans. In the film, we can observe a universal process which normally is invisible: the very beginning of an animal’s life. A single cell is transformed into a complete, complex living organism with a beating heart and running bloodstream.
These nudibranchs (sea slugs) are lit up like the midway at a county fair because they’re warning predators that they use stinging cells called nematocysts to defend themselves when attacked. But the nematocysts are not native to nudibranch physiology — they hoover them up from hydroids, a jellyfish relative, and distribute them around their bodies.
The nudibranch’s gut has fingerlike branches that extend up into the long cerata on its back. The unfired stingers travel up into the cerata and concentrate in little sacs at the tips, where they continue to develop.
If a fish or crab tries to bite the nudibranch, it squeezes those sacs and shoots out the stingers, which immediately pop in the predator’s mouth. It doesn’t take long for predators to avoid the brightly colored nudibranchs.
What a wild adaptation! (via the kid should see this)
Bumblebee, honey bee, yellow jacket, paper wasp…what’s the difference? I don’t know if this comprehensive guide to Yellow Stripey Things is entirely truthful or not — a bumblebee is “actually a flying panda” and a yellow jacket “is just an asshole” — but it is pretty entertaining. Has anyone fact-checked this thing?
Ok fine, I’ll do it!1
Carpenter bees are mostly harmless:
Male carpenter bees are quite aggressive, often hovering in front of people who are around the nests. The males are quite harmless, however, since they lack stingers. Female carpenter bees can inflict a painful sting but seldom will unless they are handled or molested.
Honey bees don’t always sting just once:
A honey bee that is away from the hive foraging for nectar or pollen will rarely sting, except when stepped on or roughly handled. Honey bees will actively seek out and sting when they perceive the hive to be threatened, often being alerted to this by the release of attack pheromones (below).
Although it is widely believed that a worker honey bee can sting only once, this is a partial misconception: although the stinger is in fact barbed so that it lodges in the victim’s skin, tearing loose from the bee’s abdomen and leading to its death in minutes, this only happens if the skin of the victim is sufficiently thick, such as a mammal’s.
Bumblebees:
Queen and worker bumblebees can sting. Unlike in honeybees, a bumblebee’s sting lacks barbs, so the bee can sting repeatedly without injuring itself; by the same token, the sting is not left in the wound. Bumblebee species are not normally aggressive, but may sting in defence of their nest, or if harmed.
And yes, you can actually pet a bumblebee:
Hoverflies don’t sting. But paper wasps do and their sting can be deadly:
Unlike yellowjackets and hornets, which can be very aggressive, polistine paper wasps will generally only attack if they themselves or their nest are threatened. Since their territoriality can lead to attacks on people, and because their stings are quite painful and can produce a potentially fatal anaphylactic reaction in some individuals, nests in human-inhabited areas may present an unacceptable hazard
I couldn’t find a good all-in-one source about yellow jackets, but by all accounts, they are aggressive and easily agitated.
The cicada killer wasp look fierce but are generally only dangerous to cicadas:
Solitary wasps (such as the eastern cicada killer) are very different in their behavior from the social wasps such as hornets, yellowjackets, and paper wasps. Cicada killer females use their sting to paralyze their prey (cicadas) rather than to defend their nests; unlike most social wasps and bees, they do not attempt to sting unless handled roughly.
Mud daubers don’t sting people that often and prey on spiders:
Black and yellow mud daubers primarily prey on relatively small, colorful spiders, such as crab spiders (and related groups), orb weavers and some jumping spiders. They usually find them in and around vegetation. Blue mud daubers are the main predator of the black and brown widow spiders.
All in all, this checks out.
Bonus stinging insect fact: There’s a sting pain index that entomologist Justin Schmidt first came up with in the 80s. Schmidt has been stung by almost everything with a stinger and rated the stings on a scale of 1 to 4 (least to most painful). He has also described the stings of individual insects more colorfully:
Western honey bee (level 2) — “Burning, corrosive, but you can handle it. A flaming match head lands on your arm and is quenched first with lye then with sulfuric acid.”
Giant paper wasp (level 3) — “There are gods, and they do throw thunderbolts. Poseidon has rammed his trident into your breast.”
Sarah Zhang writes about a support group on Facebook for people who have discovered surprising parentage through DNA testing.
Lisa, 44, admits she is still trying to go of that anger. She had always felt out of place in her family. Her hair — which she always straightened — was naturally fine and curly, her skin dark. “People would think I’m Hispanic, and would speak Spanish to me on the street,” she says. So when an DNA test in 2015 revealed her biological father was likely African American, it clicked into place. But her mom denied it. “She wouldn’t answer me. She would change the subject,” recalls Lisa. When she kept pressing, her mother broke down, saying it would destroy the family and that her dad — the man she grew up with — would kill her. She refused to say anything else about Lisa’s biological father.
I’ve written about this before (here and here) and reading these stories never gets any less heartbreaking. Back in 2010, I shared this:
I know someone who adopted a baby and they have never told her that she’s adopted and don’t plan to (she’s now in her 20s). When DNA testing becomes commonplace in another 5-15 years, I wonder how long that secret will last and what her reaction will be.
DNA testing confirms what we should have known all along: family is more than what biology says it is. Families already look quite differently than they did 40-50 years ago and they will continue to shift in the future, MAGA be damned.
Chantel Tattoli’s piece for The Paris Review, The Surprising History (and Future) of Fingerprints, is interesting throughout, but these two things leapt from the screen (italics mine):
It is true that every print is unique to every finger, even for identical twins, who share the same genetic code. Fingerprints are formed by friction from touching the walls of our mother’s womb. Sometimes they are called “chanced impressions.” By Week 19, about four months before we are issued into the world, they are set.
WHAT?! Is this true? A cursory search shows this might indeed be the case, although it looks as though there’s not established scientific consensus around the process.
Also, Picasso was fingerprinted as a suspect in the theft of the Mona Lisa from the Louvre:
When French authorities interrogated Pablo Picasso, in 1911, at the Palais de Justice about the theft of the Mona Lisa from the Louvre that August, he was clad in his favorite red-and-white polka-dot shirt. Picasso cried. He begged forgiveness. He was in possession of two statuettes filched from the museum, but he hadn’t taken her.
“In possession of”? Turns out a pal of Picasso’s lifted the statuettes from the museum, which was notoriously easy to steal from, and sold them to the artist, who knew exactly what he was buying.
True to Pieret’s testimony, Picasso kept two stolen Iberian statues buried in a cupboard in his Paris apartment. Despite the artist’s later protestations of ignorance there could be no mistaking their origins. The bottom of each was stamped in bold: PROPERTY OF THE MUSÉE DU LOUVRE.
Fingerprint art by Evan Roth. (via @claytoncubitt)
In Knowable Magazine, Rachel Ehrenberg writes about the tricky business of understanding what a tree is. Trees are tall, woody, long-lived and have tree-like genes, right? Not always…
If one is pressed to describe what makes a tree a tree, long life is right up there with wood and height. While many plants have a predictably limited life span (what scientists call “programmed senescence”), trees don’t, and many persist for centuries. In fact, that trait — indefinite growth — could be science’s tidiest demarcation of treeness, even more than woodiness. Yet it’s only helpful to a point. We think we know what trees are, but they slip through the fingers when we try to define them.
Ehrenberg then suggests that we should think about tree-ness as a verb rather than a noun.
Maybe it’s time to start thinking of tree as a verb, rather than a noun - tree-ing, or tree-ifying. It’s a strategy, a way of being, like swimming or flying, even though to our eyes it’s happening in very slow motion.
This reminds me of one of Austin Kleon’s strategies for How to Keep Going: “forget the noun, do the verb”. Hey, it seems to be working for the trees. (via @robgmacfarlane)
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