The anus is an evolutionary marvel(theatlantic.com)
theatlantic.com
The anus is an evolutionary marvel
https://www.theatlantic.com/science/archive/2021/05/evolution-butts/618915/
216 comments
> the pyloric sphincteric
Fun fact: I had pyloric stenosis as an infant. IIRC, this condition tends to hit first born males of which I am one.
Dearest mother kept bringing me into the hospital. "He keeps throwing up no matter what." She kept being told the "oh you're just a new mother" song until finally one doctor switched on a lightbulb to check something out.
Next thing is that I'm this infant on an adult stretcher being prep'd for surgery.
My oldest scar.
I swear if I was born 100 years earlier I'd be dead by starvation at no fault of anything but medical innovation.
Fun fact: I had pyloric stenosis as an infant. IIRC, this condition tends to hit first born males of which I am one.
Dearest mother kept bringing me into the hospital. "He keeps throwing up no matter what." She kept being told the "oh you're just a new mother" song until finally one doctor switched on a lightbulb to check something out.
Next thing is that I'm this infant on an adult stretcher being prep'd for surgery.
My oldest scar.
I swear if I was born 100 years earlier I'd be dead by starvation at no fault of anything but medical innovation.
Dude. I almost wrote thr same comment yesterday. I love science today because of this. Also my oldest scar.
Wouldn't dehydration hit before starvation?
In any case, congratulations on your continued survival!
In any case, congratulations on your continued survival!
When you say “switched on a lightbulb” is that figurative? Or did bright light somehow make your condition apparent? Sorry if I’m being daft here.
Figurative. As in "fine, let's just check this out because you keep coming back and why not?" which turned into "well heck, it is this condition -- page Dr Smith, we need paediatrics in surgery".
I'm convinced that who ever came up with this valve was inspired by anuses. Its a clever way to dispense honey without making a mess.
Anus inspired honey dispenser https://imgur.com/a/jmQUSYr
Anus inspired honey dispenser https://imgur.com/a/jmQUSYr
Is this safe for work? Because I'm interested, but currently on a work computer.
It looks like a squeezable honey bottle that can prolapse (not what I expected to write on HN today).
...that's not what a prolapse is. A prolapse is when the internal bits get distended, or otherwise protrude through the orifice when it's supposed to be "closed". That hone bottle is working as designed.
Yes it's just the tops of honey bottles
What is this kind of valve called?
To me the most fascinating aspect is not filtering out large chunks, but that it prevents the highly acidic gastric fluid (the pH ranges from 1 to 3) in the stomach from reaching and damaging the small intestine. The stomach is equipped to deal with the extremely acidic fluid for digestion, but the small intestine is not.
Neutralization of acid is actually done in the duodenum. We have organs called Brunner's glands lining the top half of the duodenum that secret a special mix of alkaline bicarbonates and growth factors in a thick mucin carrier. This neutralizes the gastric acids and lines the small intestines with protective mucus.
You're right though, the engineering that goes into our bodily machines is mind boggling.
You're right though, the engineering that goes into our bodily machines is mind boggling.
Man.. I wish there were more research and therapies in this regard... I've been on PPI for over 20 years because of consistent heartburn... (Sliding hernia). The operation to "fix" it they wrapped your stomach around your oesophagus but that seems like not a great solution..
You will soon have other options:
https://www.implantica.com/im-refluxstop/patients/gastrointe...
https://www.implantica.com/im-refluxstop/patients/gastrointe...
Anecdotes are not data but I was able to stop a long history of upper GI issues (and terrible heartburn and acid reflux) by drastically changing my diet. Turns out I'm not compatible with the standard western food staples.
The Western diet is horrible in all honesty. Eliminate carbs and red meats (the core of Western diets) and it creates a world of a difference for many folks, from people trying to achieve ketosis to people suffering from Crohns. Incidentally my Crohns was latent for quite a few years and only flared up when I moved West.
I was happily surprised the first time I tried a low carb diet to lose weight, as it also completely resolved my reflux issues.
Mine is low carb, but also no wheat. Even when I do small (or even sometimes medium) amounts of rice, enough to absolutely not be in ketosis, I am still better than I was when eating bread or bread-containing/adjacent things (breading, pasta, sandwiches, et c). We know I'm not celiac. Perhaps it's some weird allergy; in addition to acid reflux eating such things also used to cause me ENT issues like coughing/congestion which have gone away entirely since I stopped. None of the traditional "allergic reaction" symptoms, though.
Who knows?
All I know is that it's different for everyone and for lots and lots of people, eating totally normal things is what causes or contributes to lots of bad symptoms misattributed to some disease or disorder. More often than not it's not you, it's the utter garbage food that our society has standardized upon. Just because it's common to eat a sandwich, or pasta, or a bowl of cereal or granola, or a bagel doesn't mean that human evolution has caught up with it yet.
Who knows?
All I know is that it's different for everyone and for lots and lots of people, eating totally normal things is what causes or contributes to lots of bad symptoms misattributed to some disease or disorder. More often than not it's not you, it's the utter garbage food that our society has standardized upon. Just because it's common to eat a sandwich, or pasta, or a bowl of cereal or granola, or a bagel doesn't mean that human evolution has caught up with it yet.
Have you tried cutting out coffee and dark tea? Both myself and my mom have found that it decreases ongoing throat irritation and coughs that run in our family.
Fortunately for me coffee and tea are some of the completely harmless/fine foods, at least to my body. I can even use heavy cream and sucralose with no issues.
I live on espresso/tea, heavy cream, protein/nutrition shakes, zero-cal flavor syrups, and grilled beef. It's sort of crazy how much healthier I am eating this than if I ate, say, even healthy sandwiches. My body just seems to dig being primarily a carnivore. If I personally liked vegetables and leafy greens more I would probably do vegan keto, as I don't like how unsustainable western meat production is, but I simply can't get into the idea of leafs as food.
I live on espresso/tea, heavy cream, protein/nutrition shakes, zero-cal flavor syrups, and grilled beef. It's sort of crazy how much healthier I am eating this than if I ate, say, even healthy sandwiches. My body just seems to dig being primarily a carnivore. If I personally liked vegetables and leafy greens more I would probably do vegan keto, as I don't like how unsustainable western meat production is, but I simply can't get into the idea of leafs as food.
I’m in awe at how much time and countless generations it took to evolve these mechanisms.
>It uses an ingenious mechanism to selectively pass liquid and very small particles to the small intestine, while keeping larger chunks in the stomach for further digestion
Do you have an ELI5 for how this works?
Do you have an ELI5 for how this works?
Sure, hold out your hands in front of you like you're holding a hose with both hands vertically, one fist on top of the other. Imagine the tube is hanging from a bag full of liquid (a stomach). Now squeeze your bottom fist, and relax your top fist, and imagine the liquid filling the top part of the hose. Now relax your bottom fist a bit and squeeze your top fist, and image liquid squirting out both ends of the top part of the hose-- both forward into the bottom part and upward back toward the stomach. That's a good model of your pylorus, except the bottom fist is more like a ring, and the tube isn't vertical but horizontal, and in fact, the bottom of your stomach curves around such that the pylorus is actually squirting liquid (called chyme) upward into your small intestine.
But the vertical fists model helps to visualize the pylorus as a "cylinder" of annular muscle segments that contract and relax with alternating timing to pump liquid from the stomach into the duodenum in precise metered doses. This timed and coordinated squeezing action is called peristalsis, and is the mode of action of all your intestines as well as your esophagus.
Now here's the important part: notice that when you squeezed your top fist, liquid squirted out in both directions. Dynamic studies of the pylorus in action show that these two "squirts" are not the same. The forward squirt is usually smaller and contains only liquid and fine particles of food, whereas the larger backward squirt (called retropulsion) contains all of the large chunks of food that require further digestion.
So how does the pylorus do this? The answer lies largely in the shape and structure of the sphincter wall, and here's where it gets really crazy. The pyloric cylinder has two sets of muscles moving it: the big strong external rings of muscle, and a finer inner layer of muscle in the mucosal lining. When these muscles contract and relax, the inner mucosal lining forms various patterns of folds and wrinkles. When the pylorus is pumping liquid from the stomach to the small intestine, the two sets of muscles work together to shape folds and wrinkles that "grip" chunks of food, prevent them from passing, and then launch them backward, back into the stomach. The shapes of the folds is highly variable, and it appears that your pylorus adapts these intricate patterns in its lining from moment to moment based on the properties of the food in your stomach-- it's texture, viscosity, the shapes and sizes of the chunks in it, etc.
How does your stomach "know" these details about the food in it? I don't think anybody really knows yet.
In case anyone's looking for an exact source, here's the money quote from page 62 of the book:
> A certain contraction of the outer muscular tube is necessary for the formation of macroscopic mucosal folds. The variability of the fold pattern is also dependent on the hydrodynamic action of the fluid content of the submucosa, which in turn depends on the degree of filling of the blood vessels; the mass of mucous membrane, and consequently the volume of its folds, is regulated by the varying vascularity in the submucosa.
> In addition Forssell showed that the surface of the mucosa, or mucosal relief pattern, may vary from moment to moment; these movements are independent of, but co-ordinated with the contractions of the muscularis externa. Especially in the small intestine, but also in the stomach, various active contractile shapes, in some of which the mucosa "grips" particles of food, may be discerned. These consist of digestion chambers, blocking or filtering devices, re-absorption reservoirs and smooth or corrugated transporting tubes. In this way each region may best meet the varying demands placed on it from moment to moment, namely digestion, storage, absorption and transport respectively. One moment the mucosa may be occupied with one task, the next with another. Forsell called the inherent ability of the mucosa to move "mucosal autoplastik", providing a working relief pattern. It also determined to a large extent the number, position and form of the folds. While the coarser breakdown of food particles is effected by contractions of the muscularis externa, the finer dispersion occurs through changes in the relief pattern of the mucosa, which may enhance or counteract effects of contraction of the muscular walls. The special contractile organ of the mucous membrane is the muscularis mucosae; being attached to the mucosa and being incorporated in the submucosa, it is able to displace the former in different directions.
---
EDIT
It's been almost twenty years since I read this book, and re-reading the quote above, I realize that this wild mechanism I described is also used in the small intestine (not just in the distal stomach and pylorus). It makes perfect sense, but it never occurred to me that this is how a whole lot of our guts work to move and process food. It's kind of another epiphany for me.
But the vertical fists model helps to visualize the pylorus as a "cylinder" of annular muscle segments that contract and relax with alternating timing to pump liquid from the stomach into the duodenum in precise metered doses. This timed and coordinated squeezing action is called peristalsis, and is the mode of action of all your intestines as well as your esophagus.
Now here's the important part: notice that when you squeezed your top fist, liquid squirted out in both directions. Dynamic studies of the pylorus in action show that these two "squirts" are not the same. The forward squirt is usually smaller and contains only liquid and fine particles of food, whereas the larger backward squirt (called retropulsion) contains all of the large chunks of food that require further digestion.
So how does the pylorus do this? The answer lies largely in the shape and structure of the sphincter wall, and here's where it gets really crazy. The pyloric cylinder has two sets of muscles moving it: the big strong external rings of muscle, and a finer inner layer of muscle in the mucosal lining. When these muscles contract and relax, the inner mucosal lining forms various patterns of folds and wrinkles. When the pylorus is pumping liquid from the stomach to the small intestine, the two sets of muscles work together to shape folds and wrinkles that "grip" chunks of food, prevent them from passing, and then launch them backward, back into the stomach. The shapes of the folds is highly variable, and it appears that your pylorus adapts these intricate patterns in its lining from moment to moment based on the properties of the food in your stomach-- it's texture, viscosity, the shapes and sizes of the chunks in it, etc.
How does your stomach "know" these details about the food in it? I don't think anybody really knows yet.
In case anyone's looking for an exact source, here's the money quote from page 62 of the book:
> A certain contraction of the outer muscular tube is necessary for the formation of macroscopic mucosal folds. The variability of the fold pattern is also dependent on the hydrodynamic action of the fluid content of the submucosa, which in turn depends on the degree of filling of the blood vessels; the mass of mucous membrane, and consequently the volume of its folds, is regulated by the varying vascularity in the submucosa.
> In addition Forssell showed that the surface of the mucosa, or mucosal relief pattern, may vary from moment to moment; these movements are independent of, but co-ordinated with the contractions of the muscularis externa. Especially in the small intestine, but also in the stomach, various active contractile shapes, in some of which the mucosa "grips" particles of food, may be discerned. These consist of digestion chambers, blocking or filtering devices, re-absorption reservoirs and smooth or corrugated transporting tubes. In this way each region may best meet the varying demands placed on it from moment to moment, namely digestion, storage, absorption and transport respectively. One moment the mucosa may be occupied with one task, the next with another. Forsell called the inherent ability of the mucosa to move "mucosal autoplastik", providing a working relief pattern. It also determined to a large extent the number, position and form of the folds. While the coarser breakdown of food particles is effected by contractions of the muscularis externa, the finer dispersion occurs through changes in the relief pattern of the mucosa, which may enhance or counteract effects of contraction of the muscular walls. The special contractile organ of the mucous membrane is the muscularis mucosae; being attached to the mucosa and being incorporated in the submucosa, it is able to displace the former in different directions.
---
EDIT
It's been almost twenty years since I read this book, and re-reading the quote above, I realize that this wild mechanism I described is also used in the small intestine (not just in the distal stomach and pylorus). It makes perfect sense, but it never occurred to me that this is how a whole lot of our guts work to move and process food. It's kind of another epiphany for me.
So does it eventually give up and allow bigger objects through? You’d think it would need a mechanism to handle undigestible items (as any dog owner knows)
In my dog-owning experience, the mechanism to handle undigestible items is to vomit them back out.
It's funny with dogs, how nuts come out from the other side as they came in, untouched by a single enzyme
My uncle had a dog who loved nothing more than to eat socks, and poop them out.
It definitely does, and it's normal operation. We're supposed to eat lots of indigestible material; whole vegetables and grains contain a lot of indigestible fiber, which is necessary to support a healthy gut biome and efficient bowel operation. Corn husks, for example, are easy to see when they come out the other end.
So here again, how does your stomach "know" when to stop trying to digest certain pieces of food and let them pass on to the small intestine? This topic is called gastric emptying, and it's a whole other rabbit trail. Your stomach monitors the chemistry of the food in it-- specifically, the chemistry of the digestion products generated as the food breaks down. It knows lots of details about the carbohydrate, protein, and fat being released, and it knows how quickly its digestive enzymes and acids are being used up. So it knows how much more work needs to be done, and whether or not its worth trying to get more nutrients out of a piece of unchewed nut, for example.
There are many other variables, and I think digestion is still largely shrouded in mystery. Studies have shown variation in gastric emptying rates based on the biological activity of food, infections in gut tissues (even if they're subclinical, i.e., you don't feel unwell), time of day, and even the person's emotional state. The guts are the seat of a large part of the autonomous nervous system, and science has barely scratched the surface of it.
So here again, how does your stomach "know" when to stop trying to digest certain pieces of food and let them pass on to the small intestine? This topic is called gastric emptying, and it's a whole other rabbit trail. Your stomach monitors the chemistry of the food in it-- specifically, the chemistry of the digestion products generated as the food breaks down. It knows lots of details about the carbohydrate, protein, and fat being released, and it knows how quickly its digestive enzymes and acids are being used up. So it knows how much more work needs to be done, and whether or not its worth trying to get more nutrients out of a piece of unchewed nut, for example.
There are many other variables, and I think digestion is still largely shrouded in mystery. Studies have shown variation in gastric emptying rates based on the biological activity of food, infections in gut tissues (even if they're subclinical, i.e., you don't feel unwell), time of day, and even the person's emotional state. The guts are the seat of a large part of the autonomous nervous system, and science has barely scratched the surface of it.
This book is not super friendly to a newcomer to the sphinctor. I was unable to finish the Introduction due to the unexplained technical jargon immediately presented.
It does assume some background knowledge on the part of the reader, but that's a necessary feature of any advanced technical book or treatise.
I'm not an expert in, well, anything, so I rely a lot on Wikipedia for the basics.
I'm not an expert in, well, anything, so I rely a lot on Wikipedia for the basics.
A kindred spirit! You and i must be among a select group of individuals.
I can't hear talk of Pyloric Valves now without thinking of Confederacy of Dunces: https://en.wikipedia.org/wiki/A_Confederacy_of_Dunces (Great book btw)
My university CS department worked with a nearby hospital, and student projects were often related to medical imaging or modeling topics.
For a few years, there was work related to the anus, which according to the staff was an under-studied topic for obvious reasons.
I'm afraid I chickened out of choosing the "model the anal sphincter" project. In retrospect it sounded fun and interesting.
For a few years, there was work related to the anus, which according to the staff was an under-studied topic for obvious reasons.
I'm afraid I chickened out of choosing the "model the anal sphincter" project. In retrospect it sounded fun and interesting.
The stuff about evolving the digestive tract to get more out of food is super interesting and never thought about it.
The whole thing about human buttocks as well I recently learned about after getting a dog of my own (ya ya, covid puppy acquirer here). I was always weirded out by my childhood dog's butt and read up on it while I was researching dog ownership before I got my current little buddy. I figured I was going to have to wipe his butt to ease my slight-yet-ever-present faecal phobia. I then learned that dogs (and most mammals) actually prolapse pretty extremely when pooping, making it so that poop rarely touches their butts (at least on short haired dogs). As it turns out, my pup's butt is generally the least smelly part of him!
Anyway, a bit of a ramble about a dog's butt that many probably already know, but(t) I found it fascinating.
The whole thing about human buttocks as well I recently learned about after getting a dog of my own (ya ya, covid puppy acquirer here). I was always weirded out by my childhood dog's butt and read up on it while I was researching dog ownership before I got my current little buddy. I figured I was going to have to wipe his butt to ease my slight-yet-ever-present faecal phobia. I then learned that dogs (and most mammals) actually prolapse pretty extremely when pooping, making it so that poop rarely touches their butts (at least on short haired dogs). As it turns out, my pup's butt is generally the least smelly part of him!
Anyway, a bit of a ramble about a dog's butt that many probably already know, but(t) I found it fascinating.
> my pup's butt is generally the least smelly part of him
The mind boggles at how you've determined this...
But indeed the digestive tract is what makes us tori and not spheres.
The mind boggles at how you've determined this...
But indeed the digestive tract is what makes us tori and not spheres.
Not too much of a mystery here... my dog's tail is constantly up with his butt on full display, so it's easy to establish a safe proximity to give it a quick sniff to alleviate my fears that his butt will smell terrible (I haven't actually done this in months). To get a little more specific from my prior claims, his butt actually smells like literally nothing, and yes, I do mean "literally". Every other part of him has some kind of smell, especially his paws and face. Well, I've never put my face anywhere near his reproductive bits so I have no info there. I do, however, always give that area a quick wipe whenever we get in from a walk (he's a small dog).
Hopefully this isn't TMI and in the spirit of this article!
Hopefully this isn't TMI and in the spirit of this article!
This really turns up the curiosity related to questioning what exactly dogs are smelling when they do this to each other.
They're smelling anal gland secretions, which are too subtle for humans to detect.
That might be what they're sniffing, but anal gland secretions are not subtle. They're the opposite of subtle.
I have a lot of dogs. Every once in a while, it seems that one of them gets a plugged up anal gland, or it doesn't get fully expressed when they poop. An earlier commenter said to look for liquid dropping out when they poop; I see this all the time. But sometimes that doesn't work for whatever reason, and then later on the gland "pops" and all the stuff comes out. The dog is usually sitting on my lap when this happens. It happens with both girl and boy dogs. My wife calls it getting butt-juiced.
The smell causes me to immediately change my clothes. It's not a fecal smell. I can't begin to describe it, but once you smell it you'll never forget.
Years ago we fostered a girl dachshund who loved my wife but hated me and feared me like the devil himself. Often when I would approach her in any but the slowest and most non-threatening way, she would tense violently and squirt anal gland juice like a skunk. Sometimes she'd leave a trail of the stuff on the floor as she ran for her life. One whiff would tell you it wasn't urine.
(BTW, that poor girl dog was eventually adopted by a sweet single woman and they are now inseperable companions)
I have a lot of dogs. Every once in a while, it seems that one of them gets a plugged up anal gland, or it doesn't get fully expressed when they poop. An earlier commenter said to look for liquid dropping out when they poop; I see this all the time. But sometimes that doesn't work for whatever reason, and then later on the gland "pops" and all the stuff comes out. The dog is usually sitting on my lap when this happens. It happens with both girl and boy dogs. My wife calls it getting butt-juiced.
The smell causes me to immediately change my clothes. It's not a fecal smell. I can't begin to describe it, but once you smell it you'll never forget.
Years ago we fostered a girl dachshund who loved my wife but hated me and feared me like the devil himself. Often when I would approach her in any but the slowest and most non-threatening way, she would tense violently and squirt anal gland juice like a skunk. Sometimes she'd leave a trail of the stuff on the floor as she ran for her life. One whiff would tell you it wasn't urine.
(BTW, that poor girl dog was eventually adopted by a sweet single woman and they are now inseperable companions)
> The smell causes me to immediately change my clothes. It's not a fecal smell. I can't begin to describe it, but once you smell it you'll never forget.
I'm sorry to put this in your head but... fish sauce.
I'm sorry to put this in your head but... fish sauce.
This is true. I meant that they are subtle in the amount available when dogs butt-sniff each other. Dogs can detect the tiniest amount, way before a human even notices it's there. The concentrated stuff is, as you say, very intense.
Ah right, of course, that makes sense.
With really old dogs the gland sometimes won't unblock itself and becomes infected. The cure is to milk it. This is a vet's least favourite job, and they have some pretty grim tasks.
Source: I heard it from a vet.
Source: I heard it from a vet.
> The mind boggles at how you've determined this...
Depending on pup, you can easily get a bunch of body parts shoved into smelling distance without any effort other than continuing to be alive. Then it's just a matter of recall and forming an opinion.
Depending on pup, you can easily get a bunch of body parts shoved into smelling distance without any effort other than continuing to be alive. Then it's just a matter of recall and forming an opinion.
Dogs tend to be pretty physically close to humans. If your dog had stank-ass, you'd know it.
[deleted]
How much is humans needing to wipe their behind after pooping not simply modern dietary habits?
There are a great many such things, such as that skeletal remains of old civilizations showing very good teeth for civilizations wherein the brushing thereof was nonexistent, but the diet contained no added sugars.
There are a great many such things, such as that skeletal remains of old civilizations showing very good teeth for civilizations wherein the brushing thereof was nonexistent, but the diet contained no added sugars.
It's also because most of us poop in a sitting position.
Squatting, as you would do outdoors if you didn't have a toilet, spreads the buttocks and there is much less cleaning needed. It also promotes more complete emptying so you don't have fecal matter left "pinched" in the anus that needs to be wiped up. If you use a typical western toilet, get something like a Squatty Potty to prop up your feet and you'll find you need to do much less wiping.
Squatting, as you would do outdoors if you didn't have a toilet, spreads the buttocks and there is much less cleaning needed. It also promotes more complete emptying so you don't have fecal matter left "pinched" in the anus that needs to be wiped up. If you use a typical western toilet, get something like a Squatty Potty to prop up your feet and you'll find you need to do much less wiping.
I don't use a Squatty Potty, I just spread my cheeks as I go to sit down. I barely have to wipe if at all, and I don't have that great of a diet. This method works on any toilet seat (work, school, friend's house, etc) - no feet prop required.
Absolutely! While we do have these fatty buttocks and... er, well, we're in polite company here, but... stuff will rub up against them if pooping in any other position than a squat... but ya, in past dietary experiments I've done, I didn't actually need to wipe. I still did, of course, but it was truly unnecessary.
I spread my cheeks as I go to sit down on the toilet seat. Thus I only have to wipe very little if at all, and I don't have the best of diets. Do other people not do that?
I only do this when I shit from the window of an automobile.
Is that a joke/reference? It doesn't make sense. There must be a more efficient/reasonable way to defecate.
https://www.urbandictionary.com/define.php?term=Clean%20Brea...
A rare and treasured occurrence indeed.
A rare and treasured occurrence indeed.
Not that many because most of the world uses water and flush which is far cleaner. But it seems Westerners think their society is so superior, that they haven't figured this out this one simple trick yet.
In the West I have to go through meetings knowing how unclean everyone's bottoms are /s
In the West I have to go through meetings knowing how unclean everyone's bottoms are /s
This doesn't make me want to own a dog, but it does answer some questions I had about its hygiene. Especially the hairier dogs, I know their butt is hairless but with all that nearby hair things cannot end well.
Yes, I very specifically chose a shorthaired (fur) dog and this was one of the reasons. He is going to shed a hell of a lot when he's older but it is one con out of many pros. But yes, with very hairy dogs, the poop will touch it--they do keep it clean themselves but still...
I'm not trying to convince you to get a dog or anything, but I never wanted one and it completely changed my life in so many positive ways. I'm getting outside regularly, I've made new friends, I've developed acquaintanceships with several awesome people in my neighbour, I talk to strangers, and my weekends now have structure which has made me incredibly productive in my personal projects--I now view the downtime I have between walks and general caretaking of my pup as very precious and not to be wasted whereas before I could spend an entire Saturday in bed if I felt like it.
I'm not trying to convince you to get a dog or anything, but I never wanted one and it completely changed my life in so many positive ways. I'm getting outside regularly, I've made new friends, I've developed acquaintanceships with several awesome people in my neighbour, I talk to strangers, and my weekends now have structure which has made me incredibly productive in my personal projects--I now view the downtime I have between walks and general caretaking of my pup as very precious and not to be wasted whereas before I could spend an entire Saturday in bed if I felt like it.
Poodle and Maltese owner here. Yes, long haired dogs have dingleberry issues. We often have to shave the but area between groomings. Baby wipes are useful when said dogs have loose stools.
Maybe not a HN worthy comment here, but poodles are such amazing dogs. No offence if you have chosen to give yours the classic poodle haircut, but it's funny how said cut causes people to think of poodles as these fragile, precious, chichi dogs. They are so friendly, intelligent, hilarious--and I can only assume loveable--and a huge personality. Anyway, just another thing I learned after embarking into fulltime care of a canine.
(ya, I said embarking... I know what I did)
(ya, I said embarking... I know what I did)
I just want to echo your endorsement of poodles.
I and my family have had lots of dogs over the decades, and, looking back, the poodles have been my favorites. My present dog is a standard poodle who exemplifies what I like about the breed. She's smart, polite, curious, friendly, playful, and compliant. Smart and compliant in particular don't always go together in dogs, and it's a real bonus when they do.
Molly loves everyone, and is always happy to meet new people and other animals. She is nevertheless a good watchdog, who feels it's her duty to inform us if anyone (human or otherwise) approaches the property. On the other hand, as soon as we acknowledge her alerts, she stops them, which means they don't become tedious.
Poodles are retrievers, which may account for her tendency to bring me small animals, always completely unharmed, and to come and get me when she finds injured or dead animals near our house. Some birds and squirrels owe their continued lives to Molly.
I and my family have had lots of dogs over the decades, and, looking back, the poodles have been my favorites. My present dog is a standard poodle who exemplifies what I like about the breed. She's smart, polite, curious, friendly, playful, and compliant. Smart and compliant in particular don't always go together in dogs, and it's a real bonus when they do.
Molly loves everyone, and is always happy to meet new people and other animals. She is nevertheless a good watchdog, who feels it's her duty to inform us if anyone (human or otherwise) approaches the property. On the other hand, as soon as we acknowledge her alerts, she stops them, which means they don't become tedious.
Poodles are retrievers, which may account for her tendency to bring me small animals, always completely unharmed, and to come and get me when she finds injured or dead animals near our house. Some birds and squirrels owe their continued lives to Molly.
Gotta keep it clean down there is all. Make sure the hair isn't too long.
That prolapse is also important for your pup's health, and also not evenly distributed. If you think your pup's butthole doesn't smell, and your pup doesn't squeeze a bunch of butthole out with a poop, get ready to learn about anal glands.
How do you mean in regards to "evenly distributed" in regards to health? Actually, what do you mean overall? I have a pug and know full well that he will be emitting fish smells when he gets older that will sometime appear in solid form. I'm just not there yet. But am eager to hear more (I will of course google otherwise).
Obviously my pug's butt has some kind of smell because all the other dogs keep smelling it :D My complacence is more with that if he sits his butt down on my pillow, I'm not going to freak out about it. Should I be concerned about this?
Obviously my pug's butt has some kind of smell because all the other dogs keep smelling it :D My complacence is more with that if he sits his butt down on my pillow, I'm not going to freak out about it. Should I be concerned about this?
What I mean is that dogs have anal glands that need to release really awful smelling fluids, probably what you and your other dogs are noticing. When it happens naturally you will see a drip if you watch your dog do the deuce.
The uneven distribution is that not all dogs do it naturally, some need occasional assistance (you can do it but I’d recommend a quick/cheap vet visit, it’s gross and a bit of finesse). Some dogs just don’t get it done naturally and need that assistance on a regular cadence.
The health implication besides being a natural bodily process is that if it backs up, the whole solid waste system backs up.
Edit: don’t be overly worried, but do be attentive. If you see butt scooting this is probably what’s going on. (If it’s not it might be something more serious like a tapeworm. But I doubt that from what you described.)
And dogs are very attuned to the scent. If you smell it too it’s probably a good idea to go let a vet nurse squeeze out your pup’s anal glands. It’ll be a relief for pup and not at all traumatic.
The uneven distribution is that not all dogs do it naturally, some need occasional assistance (you can do it but I’d recommend a quick/cheap vet visit, it’s gross and a bit of finesse). Some dogs just don’t get it done naturally and need that assistance on a regular cadence.
The health implication besides being a natural bodily process is that if it backs up, the whole solid waste system backs up.
Edit: don’t be overly worried, but do be attentive. If you see butt scooting this is probably what’s going on. (If it’s not it might be something more serious like a tapeworm. But I doubt that from what you described.)
And dogs are very attuned to the scent. If you smell it too it’s probably a good idea to go let a vet nurse squeeze out your pup’s anal glands. It’ll be a relief for pup and not at all traumatic.
If needed, dogs will perform their own anal gland expression by sitting, pulling their hind legs up, and wiping their butt across your carpet. My dogs like to look at me when they do this like it's a fucking joke.
I've seen videos on youtube of people expressing a dog's anal glands, but I myself have never once been able to do it. There must be a special technique that I just can't get.
I've seen videos on youtube of people expressing a dog's anal glands, but I myself have never once been able to do it. There must be a special technique that I just can't get.
Our dog had an ingrown corkscrew tail (English Bulldog) which was amputated (laser surgery!) and anyway, I'm telling you this because our groomer does anal expression and said at first, it wasn't working for her because there was no tail to grab onto.
There is definitely a technique, but for $5 or $10 extra at the grooming appointment I think I can afford to go a while longer yet before I try to figure it out for myself - I mean, I know you can go on YouTube and learn pretty much anything but I just can't see myself...
There is definitely a technique, but for $5 or $10 extra at the grooming appointment I think I can afford to go a while longer yet before I try to figure it out for myself - I mean, I know you can go on YouTube and learn pretty much anything but I just can't see myself...
I wish my anus was more like a dog.
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> Any live young who pass through the reproductive tract could also be imperiled by the proximity to poop-borne pathogens. Perhaps that’s why human anuses ventured off on their own.
Clearly not, since it's not really feasible to give birth without simultaneously defecating all over the place. One of more unpalatable secrets kept from men back in the era where you were supposed to just sit in a different room and smoke your cigar.
Clearly not, since it's not really feasible to give birth without simultaneously defecating all over the place. One of more unpalatable secrets kept from men back in the era where you were supposed to just sit in a different room and smoke your cigar.
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how...how do they manage that in the delivery room? They just throw away the bedding you're on after the delivery?
Yup! paper covers / paper bedding, and the expert handling of midwives. Pretty simple and straight-forward!
P.S. also enemas were used in the past... but fortunately, interventions such as this, or pubic hair shaving are no longer ordered for women during labor and birth!
P.S. also enemas were used in the past... but fortunately, interventions such as this, or pubic hair shaving are no longer ordered for women during labor and birth!
There was an old website 'anus' - the american nihilist underground society, and the essayist that ran it claimed his work would be complete when the anus was recognized to be as holy as the mouth.
Congratulations my man.
Congratulations my man.
Im convinced that who ever came up with this valve was inspired by anuses. Its a clever way to dispense honey without making a mess.
Anus inspired honey dispenser https://imgur.com/a/jmQUSYr
Anus inspired honey dispenser https://imgur.com/a/jmQUSYr
Anus folding pattern are unique for every human being. So, they can be used as alternative to finger print.
cf Smart Pipe
https://youtu.be/DJklHwoYgBQ
If your criminal activities leave anus prints you deserve to get caught.
Someone just read your comment and got an idea for a startup.
Free name idea: Ringerprint
Fun fact: Latin had long vowels as well as long consonants. So be careful with them or else you might be calling an old woman an anus.
ānus = ring / anus
annus = year
anus = old woman
ānus = ring / anus
annus = year
anus = old woman
Follow-on fun fact: Spanish turned this particular long-consonant distinction into a different consonant, the eñe.
Ano means anus, while año means year.
One of the first sentences a student of Spanish will learn is "¿cuántos años tienes?", how old are you, literally "how many years do you have?"— often before they really grasp the distinction between ene and eñe.
Ano means anus, while año means year.
One of the first sentences a student of Spanish will learn is "¿cuántos años tienes?", how old are you, literally "how many years do you have?"— often before they really grasp the distinction between ene and eñe.
Also, the Spanish word "anillo" (ring) is derived from a diminutive form of Latin "ānus".
In a similar vein, vanilla is from Spanish diminutive of vaina (sheath), which is from Latin vagina (sheath).
> vanilla is from Spanish diminutive
I've been wondering about this! Does Spanish regularly form diminutives other than with the -it- infix? ("m'hijito" etc.) Latin forms them with -ill-, -cul-, or -ul-, and many such forms are obvious in Spanish (tomatillo / quesadilla etc.), but I've never known whether -ill- is still productive today or if those are relics from the past.
I've been wondering about this! Does Spanish regularly form diminutives other than with the -it- infix? ("m'hijito" etc.) Latin forms them with -ill-, -cul-, or -ul-, and many such forms are obvious in Spanish (tomatillo / quesadilla etc.), but I've never known whether -ill- is still productive today or if those are relics from the past.
Yes, at least in Spain. The spanish wikipedia lists a bunch of the variants [0]. I personally use -ino/a, as it is common where I grew up, but my favorite way of saying "puppy" is "perrete".
[0] https://es.wikipedia.org/wiki/Diminutivo
[0] https://es.wikipedia.org/wiki/Diminutivo
Thanks for the link!
It's fun to see a Spanish region bordering Portugal (-inho) forming diminutives with -iño and one bordering France (-ette) forming them with -ete.
It's fun to see a Spanish region bordering Portugal (-inho) forming diminutives with -iño and one bordering France (-ette) forming them with -ete.
Annular structures are ring shaped in English. Presumably through a similar path?
Yup, exact same thing - annulus being the Latin diminutive
Similar process with "homunculus" (little man) and "calculus" (little rock) and "nucleus" (little nut).
Huh. "Nucleus" is a form that looks like an adjective to me; I'd expect "nucula" for the diminutive of "nux".
And indeed I see this on etymonline:
> from Latin nucleus "kernel," from nucula "little nut," diminutive of nux (genitive nucis) "nut,"
So for whatever reason a new word was called for, and our nucleus comes from that, not from the diminutive form of "nut".
And indeed I see this on etymonline:
> from Latin nucleus "kernel," from nucula "little nut," diminutive of nux (genitive nucis) "nut,"
So for whatever reason a new word was called for, and our nucleus comes from that, not from the diminutive form of "nut".
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And events that take place yearly are called annual. Not to mention abbreviations like AD for "anno domini," the year of the lord.
ānnus = Spanish eñus = not a word?
Latin is fascinating. There are literally dozens of terms for the female reproductive organs.
That’s a result of medieval hymn writers. They would write conception/gestation/birth related hymns to the Blessed Virgin. They used an a strict rhyme scheme.
So lots of of medieval monks had to ask “What’s a term for uterus that rhymes with tempora? Ok how about viscera [intestines]? Viscera it is.” And the hymn becomes popular so now viscera means uterus or breast or something.
That’s a result of medieval hymn writers. They would write conception/gestation/birth related hymns to the Blessed Virgin. They used an a strict rhyme scheme.
So lots of of medieval monks had to ask “What’s a term for uterus that rhymes with tempora? Ok how about viscera [intestines]? Viscera it is.” And the hymn becomes popular so now viscera means uterus or breast or something.
my only problem is with hemorroids, what went wrong in the design there!!
You gotta spend more hours each day chasing prey animals to exhaustion.
Me, getting a little winded walking up the stairs after sitting in front of a computer, remembering that my body evolved to literally chase down a horse until the horse ran out of energy.
Another case of humans going against their evolutionary model.
"Going against their evolutionary model" is the primary, and in fact only way of evolving.
Oh and where is the evolutionary model supposed to lead us then?
We're supposed to squat, not sit, when eliminating.
Just spread your cheeks as you go to sit down on the toilet seat, and you can rest your elbows on your thighs. Mechanically it is like squating. I barely have to wipe if at all sometimes, and I don't have that great of a diet.
And have a different diet, probably
Nice thing about evolution is that if everyone keeps eating plastic for a few centuries, eventually we'll evolve to digest it properly.
Of course most will die at first. But that's a price evolution is always willing to pay.
Of course most will die at first. But that's a price evolution is always willing to pay.
Will we evolve, or will our gut bacteria evolve first?
Regardless, I am now picturing a future where evolved humans find the smell of plastic appetizing.
Regardless, I am now picturing a future where evolved humans find the smell of plastic appetizing.
Also a good way to solve gun violence, if you're very patient.
to not having hemorrhoids. i'm guessing based on context.
Evolution not keeping up with changes in diet I guess.
Do our primate cousins in the forests and zoos get hemorroids?
Do our primate cousins in the forests and zoos get hemorroids?
You're using it too much!
Squating... The sitting toilets that we have now are not good for the body.
We're all way past the evolutionary MTBF, thanks to antibiotics and vaccines. Not a lot of 20 year olds with that issue. This planet would have our current models dying of "natural causes" well before 35 if it weren't for our intentionally bucking the trend.
The human lifespan hasn't changed much throughout history, and even access to doctors don't seem to matter that much - the Amish in the US live just as long as everyone else.
What's changed is that people don't die as infants anymore.
What's changed is that people don't die as infants anymore.
I don't think that's accurate; a quick (admittedly not rigorous) search suggests that human lifespans have approximately doubled in the last 500 years or so. (The modern Amish also don't currently live in a society with endemic smallpox.)
It also doesn't make sense: vaccines and antibiotics don't just protect infants.
It also doesn't make sense: vaccines and antibiotics don't just protect infants.
The life expectancy for a 1-year old has gone something along the line of +40%. That's significant but not doubled. Infant mortality is by very large margin the most important factor in the changes to life expectancy at birth. And you can get most of the way there with just basic hygiene rules. Full on modern medicine only helps with the hedge cases.
One interesting data point is that the age at which people transition economically from accumulating wealth to transferring it has remained about the same (around 64), at least as far as Western European inheritance records prior to demographic transition show. Ie. people retire at the same age. They just spend more time being old. I'm not sure it's all that much progress. I wish we found ways of making people useful longer, rather than just trying to keep them from dying.
One interesting data point is that the age at which people transition economically from accumulating wealth to transferring it has remained about the same (around 64), at least as far as Western European inheritance records prior to demographic transition show. Ie. people retire at the same age. They just spend more time being old. I'm not sure it's all that much progress. I wish we found ways of making people useful longer, rather than just trying to keep them from dying.
The interesting number isn't average lifespan though, it's average lifespan after you reach 20.
> The modern Amish also don't currently live in a society with endemic smallpox.
That's why I said access to doctors, not to public health, which is what's kept most of us alive. Though I don't know how modern their approach to childbirth is, that one's important.
> The modern Amish also don't currently live in a society with endemic smallpox.
That's why I said access to doctors, not to public health, which is what's kept most of us alive. Though I don't know how modern their approach to childbirth is, that one's important.
If you don't die from an injury or disease, humans lived about as long as they do today. It's under 5 year old mortality, childbirth and disease and injury that made us die more on average which reduced our life expectancy.
This means that our actual durability and lifespan hasn't improved that much, just our ability to fix and avoid previously fatal injuries.
If humans weren't genetically encoded to die from old age, vs just plain wear and tear like you would with a car, you would statistically see a small amount of humans who lived until 300 today. Just like how there are thousand year old well preserved physical objects today.
This means that our actual durability and lifespan hasn't improved that much, just our ability to fix and avoid previously fatal injuries.
If humans weren't genetically encoded to die from old age, vs just plain wear and tear like you would with a car, you would statistically see a small amount of humans who lived until 300 today. Just like how there are thousand year old well preserved physical objects today.
If there was ever a time for the universal New Yorker caption:
https://web.archive.org/web/20060203045552/http://modernarth... ...
"Christ, what an evolutionary marvel!"
When I think about the digestive tract, I wonder—is the human body topologically equivalent to a torus?
It depends on the minimum size of the what you will consider a hole. Check out the video from VSauce on YouTube about how many holes a human has.
https://youtu.be/egEraZP9yXQ
https://youtu.be/egEraZP9yXQ
Specifically a g-holed torus, since the digestive tract isn't the only hole through the human body. At the very least, the mouth and ear are connected forming another hole.
Half of my comments start with "I heard a podcast the other day about this.." but I heard a podcast the other day that described how they had managed to get pigs to survive for multiple hours by inserting oxygenated liquid into their anus.
"Takanori - One is a very intuitive approach we just intubated, from the anus, just to provide oxygen gas continuously. This oxygen delivery is really able to persist survival in lethal conditions. Even up to 60 minutes or even longer.
Eva - 60 minutes of breathing through the rectum just by pumping in oxygen. Sounds amazing, but also like you could get a bit uncomfortable. The more clinically relevant approach uses a liquid that's very good at dissolving oxygen, perfluorocarbon or PFC. This liquid is already used by doctors during some ice surgeries and sometimes as a type of synthetic blood for transfusions. So we already know that it's safe for humans.
Takanori - So that liquid ventilation approach is also having greater impacts on oxygenation. So as to really rescue those fatal hypoxic conditions in the mouse, rats, and pig model system.
Eva - Incredibly, Takanori showed that when just less than a pint of this PFC was injected into the anus of pigs, they would stay happily oxygenated for up to 20 minutes when in respiratory failure. And they didn't stop there, by re-injecting every 20 minutes or so they could keep the pigs going for hours, or even more. Importantly though, when we breathe in and out using our lungs, we aren't just taking in oxygen. We're getting rid of carbon dioxide and other waste products too."
Transcript of interview: https://www.thenakedscientists.com/articles/interviews/intes...
NY Times article: https://www.nytimes.com/2021/05/14/science/rectum-breathing-...
//EDIT//Actual paper: https://www.cell.com/med/fulltext/S2666-6340(21)00153-7?utm_...
"Takanori - One is a very intuitive approach we just intubated, from the anus, just to provide oxygen gas continuously. This oxygen delivery is really able to persist survival in lethal conditions. Even up to 60 minutes or even longer.
Eva - 60 minutes of breathing through the rectum just by pumping in oxygen. Sounds amazing, but also like you could get a bit uncomfortable. The more clinically relevant approach uses a liquid that's very good at dissolving oxygen, perfluorocarbon or PFC. This liquid is already used by doctors during some ice surgeries and sometimes as a type of synthetic blood for transfusions. So we already know that it's safe for humans.
Takanori - So that liquid ventilation approach is also having greater impacts on oxygenation. So as to really rescue those fatal hypoxic conditions in the mouse, rats, and pig model system.
Eva - Incredibly, Takanori showed that when just less than a pint of this PFC was injected into the anus of pigs, they would stay happily oxygenated for up to 20 minutes when in respiratory failure. And they didn't stop there, by re-injecting every 20 minutes or so they could keep the pigs going for hours, or even more. Importantly though, when we breathe in and out using our lungs, we aren't just taking in oxygen. We're getting rid of carbon dioxide and other waste products too."
Transcript of interview: https://www.thenakedscientists.com/articles/interviews/intes...
NY Times article: https://www.nytimes.com/2021/05/14/science/rectum-breathing-...
//EDIT//Actual paper: https://www.cell.com/med/fulltext/S2666-6340(21)00153-7?utm_...
Tell that to my hemorrhoids that make me cry -and what‘s with making it pleasurable to stick stuff inside this dirtiest part of our body???
Evolution sucks.
Evolution sucks.
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get a bidet
My friend once registered the domain "myan" in the top level domain "us". All sorts of adolescent hilarity ensued.
I see the domain is now available.
I see the domain is now available.
Thanks, now "you are an evolutionary marvel" sounds like an insult.
Brilliant writing from the Atlantic.
Juvenile observation of the day: It's funny that this sits in the HN front page just above an article titled "Holes in the WiFi" :p
Not to be snarky, but isn’t every part of a successful organism an evolutionary marvel? If not, then perhaps a more interesting tale would be to look at the bodily systems that are substandard garbage. I’d probably start with the lower back.
The back is a good one.
How about this design where you stuff food in the same hole you breathe through?
Seems so unnecessarily dangerous.
How about this design where you stuff food in the same hole you breathe through?
Seems so unnecessarily dangerous.
> Seems so unnecessarily dangerous.
It's not like there's no mitigation in place in the body itself.
It's not like there's no mitigation in place in the body itself.
Sure, but that's another hack.
Evolution's solution: cough it out
Better solution: don't send food, water, and air down the same pipe in the first place
I mean, no competent engineer would design the plumbing for a building such that the same pipes were used for water and air at different times, right?
Evolution's solution: cough it out
Better solution: don't send food, water, and air down the same pipe in the first place
I mean, no competent engineer would design the plumbing for a building such that the same pipes were used for water and air at different times, right?
a software engineer would. we call it "multiplexing".
That reminds a bit of systems where the data plane and control plane are the same. Like the old AT&T phone network.
No its not just cough it out. The mechanism to avoid food and fluids is a lot more complex than that.
> Seems so unnecessarily dangerous.
I agree, but it hasn't killed enough to evolutionarily matter.
I agree, but it hasn't killed enough to evolutionarily matter.
It has for fish!
Its worse for Squid their brain is a torus shape with its esophagus running through the middle. their brain cannot stretch but their esophagus can making it so that if a squid were to swallow to large of a bite it can rip their brain.
pee and reproduction too
I've read that urination actually helps by cleaning out the urethra after ejaculation, though, stopping some diseases - which some people think might be why men have the urge to pee often after sex. So it may not be as evolutionary crazy as one would think
Same for women...
"In every final scan we could see a big, full bladder, even though most of the women went to the toilet before they went inside the MRI,” explains Pek with comical astonishment. “We think it might be evolution’s way to force women to urinate after sex. Perhaps our ancestors developed this function to avoid urinary tract infections, but that’s only a hypothesis."
https://www.vice.com/en/article/qvgkzw/the-story-of-the-dutc...
"In every final scan we could see a big, full bladder, even though most of the women went to the toilet before they went inside the MRI,” explains Pek with comical astonishment. “We think it might be evolution’s way to force women to urinate after sex. Perhaps our ancestors developed this function to avoid urinary tract infections, but that’s only a hypothesis."
https://www.vice.com/en/article/qvgkzw/the-story-of-the-dutc...
wait until you hear about the cloaca
> A cloaca is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts of many vertebrate animals.
> All amphibians, reptiles, birds, and a few mammals have this orifice, from which they excrete both urine and feces.
> Mating through the cloaca is known as cloacal copulation, commonly referred to as cloacal kiss.
> The cloacal region is also often associated with a secretory organ, the cloacal gland, which has been implicated in the scent-marking behavior of some reptiles, marsupials, amphibians, and monotremes.
> All amphibians, reptiles, birds, and a few mammals have this orifice, from which they excrete both urine and feces.
> Mating through the cloaca is known as cloacal copulation, commonly referred to as cloacal kiss.
> The cloacal region is also often associated with a secretory organ, the cloacal gland, which has been implicated in the scent-marking behavior of some reptiles, marsupials, amphibians, and monotremes.
You need mucus and it's a lot more convenient to dump it down the throat where it can pull double duty as lubricant and be recycled than have it come out the front all the time.
Given the comments here so far, I'd suggest the article's title be replaced with its subtitle:
> We have very little idea where anuses come from
This also more accurately describes what the article is about.
> We have very little idea where anuses come from
This also more accurately describes what the article is about.
Human pregnancy is not an evolutionary marvel. It brings disproportionately more suffering and is more dangerous to the mother than in other species.
All worth it for those extra few CCs of brain!
Never forget which organ is telling you this.
The size of the woman's pelvis actually restricts further evolutionary brain growth. Babies being unable to be born because of too big heads fits the very definition of an evolutionary deadend. Marsupials and eggs don't have that restriction (pun intended).
Fortunately we can now bypass this dead end with cesarean section.
The scrotum has all the marks of successive bad, hacky evolutionary patching.
Problem: Warm-bloodedness means the testicles are now too warm to work well.
Hack #1: Hang them on the outside of the body so they can stay cooler.
New problem resulting from first hack: Now they're much easier to damage.
Hack #2: Make them hurt really bad if they get bashed, so the owner takes great care to guard them.
The proper solution would have to make them more temperature-tolerant in the first place.
Interestingly, ovaries didn't go down this road, though there are certainly some suboptimal designs in that whole system as well.
Problem: Warm-bloodedness means the testicles are now too warm to work well.
Hack #1: Hang them on the outside of the body so they can stay cooler.
New problem resulting from first hack: Now they're much easier to damage.
Hack #2: Make them hurt really bad if they get bashed, so the owner takes great care to guard them.
The proper solution would have to make them more temperature-tolerant in the first place.
Interestingly, ovaries didn't go down this road, though there are certainly some suboptimal designs in that whole system as well.
Don’t forget, they can also torse and twist (just like ovaries, I might add).
I guess we humans are still an evolutionary work in progress. :D
Shudder to think what evolutionary completion looks like...
> Interestingly, ovaries didn't go down this road
A fixed quantity of viable eggs within prime child bearing years until menopause when women would then perform other roles within the community.
A fixed quantity of viable eggs within prime child bearing years until menopause when women would then perform other roles within the community.
> Not to be snarky, but isn’t every part of a successful organism an evolutionary marvel?
I prefer Stephen Jay Gould's point that lots of evolved subsystems are just kludges and jury-rigged solutions that just happen to work good enough, sort of. ("The Panda's Thumb").
I prefer Stephen Jay Gould's point that lots of evolved subsystems are just kludges and jury-rigged solutions that just happen to work good enough, sort of. ("The Panda's Thumb").
From a 2001 issue of Scientific American, If Humans Were Built to Last: https://www.researchgate.net/publication/12096406_If_Humans_...
(That 13-year-old me read at the time when I stumbled across it in my grandfather's study.)
(That 13-year-old me read at the time when I stumbled across it in my grandfather's study.)
If you read some of John Sarno's stuff on psychosomatic pain, it seems highly plausible that most pain is just psychosomatic in nature.
https://www.youtube.com/watch?v=0VyH1laOd2M good video on this
https://www.youtube.com/watch?v=0VyH1laOd2M good video on this
After curing my lower back pain through weightlifting, it seems more like a well-designed system that just needs coordinated muscle use to protect. We just aren't in the conditions that teach us how to use gluteus medius, hamstrings, and torso rotation instinctively any more.
Talk about an HN title.
Indeed. Not even a week since the last one:
Rectal Breathing with Perfluorocarbons (cell.com) https://news.ycombinator.com/item?id=27159001
Rectal Breathing with Perfluorocarbons (cell.com) https://news.ycombinator.com/item?id=27159001
Nine days since:
The Anus: Judge skeptical that Holmes’ luxury lifestyle should go before jury
https://news.ycombinator.com/item?id=27114118
The Anus: Judge skeptical that Holmes’ luxury lifestyle should go before jury
https://news.ycombinator.com/item?id=27114118
The second 'orifice' title in 24 hours, too. The previous thread ended up keeping itself together. Not sure about this one yet.
Seems like people are keeping things relatively light-hearted with some intellectually interesting side topics.
New title suggestions:
"Butts: finding the source."
or:
"Scientists Find That Hindsight is not 20/20"
"Butts: finding the source."
or:
"Scientists Find That Hindsight is not 20/20"
URL contains: 'evolution-butts'
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My wife agrees with this statement, often
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I always thought that the human embryo develops it's anus first, and that this is a indication that is was also first in evolutionary development
the article talks about how anus may have formed, yet they don't mention embryonic development which usually kind of replays some evolutionary development:
https://en.wikipedia.org/wiki/Embryological_origins_of_the_m...
https://en.wikipedia.org/wiki/Embryological_origins_of_the_m...
It turns out that evolutionary recapitulation has, at best, been oversold:
https://en.wikipedia.org/wiki/Ernst_Haeckel#Embryology_and_r...
this is why i used "some". The full recapitulation theory is obviously not true. The embryo development is an algorithm which gets branched and pruned in parallel with evolution and without deep rewrite, and thus it contains very recognizable major phases of evolutionary path to the given point that embryo belongs to.
> replays some evolutionary development:
Ontogeny recapitulates phylogeny was somewhat debunked even 150 years ago. I speak as someone who owns a dozen Ernst Haeckel first or early editions.
Is there some related underlying concept we can't put our finger on? Maybe. Just like Dunbar's number
Ontogeny recapitulates phylogeny was somewhat debunked even 150 years ago. I speak as someone who owns a dozen Ernst Haeckel first or early editions.
Is there some related underlying concept we can't put our finger on? Maybe. Just like Dunbar's number
Haeckel is "development of advanced species passes through stages represented by adult organisms of more primitive species" which obviously isn't true in general.
Our embryo though passes through the stages which were inherited from the embryos of our more primitive ancestors - the "embryo tree" structurally parallels and mirrors the evolution tree.
Our embryo though passes through the stages which were inherited from the embryos of our more primitive ancestors - the "embryo tree" structurally parallels and mirrors the evolution tree.
Yea, we learned that in highschool as well, too bad not everyone frequented this forum was afforded the privilege of going to a poorly funded public school in the inner city. Indeed facts about anuses where surprisingly easy to come by.
When I look at a brilliant, highly optimised piece of code, my first thought isn't "wow, I wonder how long and how many iterations of natural selection it look, to get this code snippet working just right". I do however, usually look at the Git blame.
A CRM is surely less sophisticated than the marvellous, multifunctional sea cucumber anus. Could I possibly wake up one day with a custom one created and deployed to one of my servers, without my intervention?
"Oh, Professor, look! I think I've got an unexpected planet! Oooh, which one's that, Professor?"
"It is Uranus, my dear," said Professor Trelawney, peering down at the chart.
"Can I look at Uranus, too, Lavender?" said Ron.
I grew up calling it 'Ur-in-us', now every seems to call it 'Ur-ay-nus'... hence the on-going childish joke.
What's the correct pronunciation?
What's the correct pronunciation?
Really. Like, not the cerebral cortex, the liver, or even the eye. Or how about pregnancy. Nope. Let’s be super impressed by a sphincter. It closes and opens.
Just because some other organs are also evolutionary marvels doesn't mean the sphincter isn't one.
It’s like going to a class of kids, narrowing down on the dumbest kid that’s consistently trouble and has a solid string of F-s and proclaiming “this child is a genius”. Maybe it is, compared to a cucumber, but your statement would still be awkward in comparison to the rest of the class.
Pretty much everything that has evolved is intricate in ways we can’t even understand. When everything is a marvel equally, nothing is. But it’s not equal. Some things are more marvelous. So we call them a marvel. It’s how words work.
Say, a green ball is also technically a red ball and blue ball. Nothing is perfectly green. But you still don’t call a brightly green ball a red ball. Because that’s how words work.
Pretty much everything that has evolved is intricate in ways we can’t even understand. When everything is a marvel equally, nothing is. But it’s not equal. Some things are more marvelous. So we call them a marvel. It’s how words work.
Say, a green ball is also technically a red ball and blue ball. Nothing is perfectly green. But you still don’t call a brightly green ball a red ball. Because that’s how words work.
To say that the anus is not a marvel is to imply that it is a completely ordinary, expected development. The article explains why it's actually a fascinating piece of evolutionary work. Because that's how words work.
So now being a "marvel" is a binary proposition. Either is something a marvel, or it's "completely ordinary, and expected". No, that's not how words work.
Also, sphincters and valves have evolved countless ways independently in living organisms (and even in structures they build), and they're omnipresent also in the machines we create.
Regulating flow in a pipeline (of any kind) is possibly one of the most basic adaptations you need in order to make a working system... of anything.
So in fact... sphincters ARE completely ordinary and expected, if you ask me. And the anus is not special relative to other sphincters (and despite The Atlantic trying to be cute about it, they really don't support their headline in the article either).
Also, sphincters and valves have evolved countless ways independently in living organisms (and even in structures they build), and they're omnipresent also in the machines we create.
Regulating flow in a pipeline (of any kind) is possibly one of the most basic adaptations you need in order to make a working system... of anything.
So in fact... sphincters ARE completely ordinary and expected, if you ask me. And the anus is not special relative to other sphincters (and despite The Atlantic trying to be cute about it, they really don't support their headline in the article either).
I once spoke with a Christian opthamologist who described how many times her professors had to remind their students that the eye was a feat of evolution, lest they reach the conclusion that this impossible engineering achievement was by the hand of God.
While this comment may draw unhelpful and undesired debate, I genuinely believe these amazing structures were created by the Word of the Almighty God and credit should be given where it is due. These are incredible designs by our omnipotent creator.
While this comment may draw unhelpful and undesired debate, I genuinely believe these amazing structures were created by the Word of the Almighty God and credit should be given where it is due. These are incredible designs by our omnipotent creator.
Not sure what should be considered helpful or desired debate; such delicate a topic. Feel free to just say "stop" and I'll enquire no further. But since you're bringing this up, I'm tempted to ask:
If credit should be given where credit is due, should we also be allowed to criticize where the design is not amazing?
If credit should be given where credit is due, should we also be allowed to criticize where the design is not amazing?
Certainly. But the criticism your likely to present is trivial to answer from a theological perspective.
why do we need to wonder when things are well made if we're going to explain away anything that we don't judge favourably as "we poor mortals cannot grasp his greatness and thus cannot really that this is indeed an instance of bad design".
Why would we mere mortals be capable of knowing good design when we see it in the first place?
Why would we mere mortals be capable of knowing good design when we see it in the first place?
Fedora tippers and fundies alike seem to vehemently agree on one really weird point - that God can not or will not create things through some kind of procedural generation. Both parts seem to think that evolution means that nobody could have deliberately and knowingly set up the initial conditions for it to happen. Which as far as I can tell doesn't follow from any of the data, whether religious or scientific.
Apart from that, all the evidence is actually on the side of the Christians, even though it's all anecdotal: scripture, patristic documents, traditions, etc. It's not quite enough to convince me, but the other side has exactly nothing, not even anecdotal evidence, on why there is something rather than nothing.
Apart from that, all the evidence is actually on the side of the Christians, even though it's all anecdotal: scripture, patristic documents, traditions, etc. It's not quite enough to convince me, but the other side has exactly nothing, not even anecdotal evidence, on why there is something rather than nothing.
What's so great about the eye? It could easily be improved and many animals have better vision than us - more distance, ability to see polarization and UV, no hole in the middle our brains have to patch up, that saccading hack, etc.
The dynamic range is quite good though.
The dynamic range is quite good though.
There was this notion that the human eye, in its astounding complexity, couldn't have evolved gradually, but had to have been created all at once, called "irreducible complexity".
https://en.wikipedia.org/wiki/Irreducible_complexity#Eye
https://en.wikipedia.org/wiki/Irreducible_complexity#Eye
The saccade bug/feature is really neat. I remember reading a whitepaper a couple years back on how it was being leveraged for foveated rendering in next gen VR headsets. Cool stuff!
I am quite interested in the difference between people's intuition about things. The more complex a system is, the less I tend to think about it being designed.. It is just too beautiful to be a crafted artifact.
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Here's a fantastic (and free) book about just this structure:
http://med.plig.org/