This article is needlessly sensational and has waaaaay too many misleading "chicken and egg" statements. The evolution of the uterus came prior to the evolution of the human embryo, so to say that the uterus "needs" to protect the body against the embryo is untrue; in reality, it was the embryo that needed to adapt itself to its environment.
It's these kind of articles that cause misunderstandings about how evolution actually works. If we, the HN community, are interested in furthering our knowledge bases, we need to stop falling for these pseudo-intelligent reskinned BuzzFeed articles.
This is faulty reasoning. To think that the female reproductive system developed prior to the fetus (in order to pave way for nurturing of the embryo) is implying evolution is a purpose-driven, goal-oriented process - a line of reasoning not too far from "intelligent design".
Not to mention the egg-chicken dichotomy is absurd. There was neither a "first chicken" nor a "first egg".
Single celled protists first developed sexual reproduction about 2 billion years ago as a means of producing genetically variable offsprings. It may be assumed both the offspring and the reproductive machinery of the parents developed concomitantly as life was making a shift from uni-cellularity toward multi-cellularity.
As for mammals (which includes us humans), the placenta, which serves as an important barrier between the mother and the fetus (only letting nutrition pass through), is of viral origin. Placental syncytiotrophoblasts SCT-1, SCT-2 proteins are derived from endogenous retroviruses. Our genome is full of fossils of viral DNA - accumulated over several millions of years. If these viruses had not apt-get install-ed biological chroot jails, we would not have been born at all.. (obviously some other modes of reproduction may have been developed)
Carl Zimmer has some interesting write-ups on this topic:
For those interested in evolution of sexual reproduction and "viro-biome", I recommend Carl Zimmer's Planet of Viruses and Matt Ridley's Red Queen.
I agree the article is a bit sensationalist. Look at it in this way: had it been a boring, academic, science-journaly piece, many of us wouldn't have waded through the article at all... Obviously the target audience for that article (and the site) are general science-buffs and not only embryologists or molecular biologists. Personally I think some dramatisation (to make the content more appealing to general audience) is acceptable - so long as the subject matter doesn't deviate too much from reality.
PS: apologies for my broken english :)
PPS: Re: the chicken & egg question - the egg came first because reptilians laid eggs. Chickens, and birds in general, are descendants of dinosaurs.
Also, if your assertion is that this article (which I admit I found fascinating) causes misunderstandings about evolution then your counter statement - "in reality, it was the embryo that needed to adapt itself to its environment" - is guilty of even greater oversimplification.
While I agree with the chicken and egg statements, I think the sensationalism is a Good Thing in this instance. The language of the article and the way the information is presented gives way to some good discussion points and thought projects. If you simply wanted more "facts" and "knowledge" of human reproduction, go read Wikipedia.
These kind of articles don't cause misunderstandings, people interpreting the language as fact, do. So long as the reader understands the language in the article, I see no problems with it. Nothing in the article states that the presented information is beyond theory. It's a discussion of those theories with supporting science thrown in where necessary to drive further questions and discussion.
Can you help me better understand your post? What I got out of it was "so long as the readers understand it's not actually true, it's ok" but I'm not convinced this is the intended interpretation.
If we think of the pragmatic and plausible theoretical model probability space for possible models that graph the change over time of the mean biological biogenesis pattern of homo Sapiens, we will find mathematical utility in using the functions in Branching Theory and Lexographic Fractal Permutation (Collation) Algorithms... Which essentially modularize and computationally compress the process of evaluating the distinct (clustered) networks in the lexograph...thus providing the capability to evaluate, compare, and communicate... The logically referenced data in the hypothetical, theoretical, and observational/proven possibility space...in a more efficient, albeit, approximate methodology.
A theoretical discussion, such as the article's, isn't trying to nail down true or false. The discussion is rooted in and follows established truths along the way to explore potential new possibilities. This is what theorizing is. If we simply sat around discussing facts and non-facts we'd never get anywhere with discovery.
A question such as "What's true and what's false?" does not prompt for knowledge expanding discussion. We want to ask things like:
* What exists as scientific fact now?
* Is what exists now provable by scientific method or is it still in theory stage?
* What seems likely and/or possible as the next steps?
* Can we test anything in the resulting discussion with scientific method to prove them?
I've read a lot of these, but it usually feels more like we're glossing over Aesop's fables with a veneer of evolutionary theory. It's interesting to read about what happens, but all the suspect explanations in the story detract from it for me.
It seems that what you really wanted to do is to criticize the narrative of the story. But you end up criticizing the factual truth of the story. Those are two different things.
Just because the words chosen to describe this piece of biology invoke a certain association between words, does not mean what they describe isn't happening. The science of conflicts within what appears to be cooperation is sound, well-proven science.
The problem with these evolutionary biology stories is that narrative always implies as if this "conflict" is somehow conciously driven. That problem is mostly caused by human language, that is not well equipped to talk about conflict without implying some drive.
The author of this article could have put more effort in toning down the conflict tone, perhaps. I don't think that would have been really necessary, but that would qualify as goor criticism. But the facts are what they are.
In grad school (mathematical biology / evolutionary genetics / adaptive speciation) we would refer to articles like this as filled with "just so stories" [0]. The descriptions aren't really based on experimental results, or really strongly evidential; they're stories that happen to explain some of the evidence.
I haven't read the article yet, but I know what you're talking about. Articles and documentaries almost always discuss natural selection as if there were intention. Even if they demonstrate that they know what they're talking about, they go on to use inaccurate language unsuitable for conveying filtered variance.
I have basically no knowledge on this topic, but my initial reaction before I even read your post was exactly that - there are quite a lot of "chicken and egg" scenarios brought up.
Some of the stuff made sense, some of it was (potentially) fascinating, some of it was quite dubious.
I shared this on Facebook, and my friend who's a perinatologist (a sub-specialist who takes care of moms delivering preterm, moms w severe medical conditions (lupus, kidney failure, heart failure) and fetuses with problems (birth defects, fetuses who need transfusions for anemia) commented, saying, "The fetus is the most successful parasite known to man. Many people even want one!"
From a purely technical viewpoint, parasitism is always antagonistic/bad.
If not, it's called mutualism or commensalism. Not disagreeing with your real point, just being pedantic.
edit: to biomcgary, two points: first - i was taught that parasitism is by definition bad but actual interactions between species can fall along a spectrum of mutualistic and parasitic (and individual and specific effects may differ). second - it really ought to be moot since these terms refer interspecific interaction, right? I did a little googling before this edit, and yes, i see intraspecific brood parasitism and such... anyway, enough digression from me. I just think it's an overly-clever corruption of the actual concept of parasitism to describe a fetus as one. It's like calling a hill a parasite because it takes effort to walk up one.
You may be trying to be pedantic, but, to be meta-pedantic, your point highlights that two different conclusions are reasonable depending on the scale of analysis. At a functional level, a fetus takes nutrients from mom without returning any benefit (thus a parasite), but from the longer term perspective of evolution the relationship is mutualistic.
Thanks for the 4 downvotes so far. I have a formal education in biology and my points were correct. Sorry about the tone. I guess we're valuing style over substance now.
I read this article on Aeon the other day -- for an ostensibly scientific approach, the author spends a lot of energy anthropomorphizing the biological processes. Plenty of what's said is rigorous and fascinating, but I think that style obscures some of it.
What's really interesting to me is that in many ways this "adversarial" relationship must actually be looked at as a fairly optimal one as far as evolution is concerned -- after all, our species (and plenty of other mammals) have reproduced and thrived across the world.
I'd be very curious to read an analysis of postpartum depression through this lens.
Interestingly, the genetic conflict described in the article approaches zero in species with lifetime monogamy because maternal and paternal fitness becomes the same. The genetic conflict increases by the degree of polygamy. edit: I'm an evolutionary biologist, but not a theoretical one, so I might not be aware of edge cases.
Monogamy should decrease sibling-sibling genetic conflict, relative to polygamy, since you can expect to be more closely related to your siblings on average. Even in ideally monogamous species, though, there is still genetic conflict between siblings, and between parents and children. Even though kin selection can drive these relationships toward cooperation, there still exists an opportunity for conflict whenever a behavior would benefit you more than twice what it would cost your sibling. The tension is heightened for parent-offspring relationships, since the expected reproductive potential of the parent is even lower from the offspring's genes' point of view. In the cases where this doesn't hold, such as in _Hymenoptera_ where females share 3/4 of their variation with their sisters through a quirk of genetics, eusociality tends to evolve and you get as conflict-free a family as you could imagine. A hive. That's what the absence of parent-offspring conflict looks like.
Even during fetal development, in which both parties have a strong interest in the survival of the other, there is a range of conditions that would be acceptable (i.e. better than nothing) to both parties. You should still expect replicating gene machines in such a scenario to claw over the surplus: the mother seeking to distribute her resources
among all her offspring in a way that maximizes her fitness, and the fetus to maximize its own.
Monogamy should decrease sibling-sibling genetic conflict, relative to polygamy, since you can expect to be more closely realted to your siblings on average. Even in ideally monogamous species, though, there is still genetic conflict between siblings, and between parents and children. Even though kin selection can drive these relationships toward cooperation, there still exists an opportunity for conflict whenever a behavior would benefit you more than twice what it would cost your sibling. The tensioned is heightened for parent-offspring relationships, since the expected reproductive potential of the parent is even lower from the offspring's genes' point of view. In the cases where this doesn't hold, such as in _Hymenoptera_ where workers share 3/4 of their variation with their sisters through a quirk of genetics, eusociality tends to evolve and you get as conflict-free a family as you could imagine. A hive. That's what the absence of parent-offspring conflict looks like.
Even during fetal development, in which both parties have a strong interest in the survival of the other, there is a range of conditions that would be acceptable (i.e. better than nothing) to both parties. You should still expect replicating gene machines in such a scenario to claw over the surplus: the mother seeking to distribute her resources
among all her offspring in a way that maximizes her fitness, and the fetus to maximize its own.
I think that depends very much on the set of goals that are considered as 'optimal'. which is a matter of definition. I would say that for constraints such as robustness and adaptability to the environment the current situation is likely close to 'optimal'.
"By eight months, the foetus spends an estimated 25 per cent of its daily protein intake on manufacturing these hormonal messages to its mother" That's a lot of energy. Further, human mothers have a high chance of death from natural childbirth compared to most mammals.
Further the energy costs, pain, and suffering from monthy periods has a lot to do with the conflict, wolves for example don't suffer nearly as much.
Realistically it's at best a local optima, but robustness and adaptability are hindered but such inefficiency.
Inefficient on an individual level, but the adaptability and robustness is more on a species level. It's probably pretty efficient in that regard.
A high risk, high reward strategy that works out well for humans that survive and end up with large brains, but terrible for certain individuals for the reasons previously outlined.
I agree with your point about anthropomorphizing. When you draw stark boundaries between mother and fetus at a biological level the fetus could be termed as adversarial but from holistic point of view the fetus becomes man or a woman and carries human race forward (in time) and also becomes part of immediate family where they create wonderful memories with their parents.
And all the pretty language in the world doesn't remove the very real dangers to the mother's life during pregnancy which we have only very recently had a decent handle on.
Agreed. Lots of stable complex systems are characterized by a "healthy" tension between opposing forces, an equilibrium maintained by negative feedback loops.
There are even more interesting implications of the "war": women are fertilized inside the body so that fathers can not be sure whose offspring a child is (because the fertilization can not be seen, other than with eggs, for example) - otherwise they might kill the offspring of other fathers (our ancestors would have, that is). Furthermore, women try to hide their fertility as much as possible, other than most other mammals. Iirc that is for the same reason: since men can not be sure when the woman was fertile, they can not be sure who made her pregnant. But if they don't know when a woman is pregnant, why even have sex? And that is why sex is fun. We take it for granted, but apparently it is only fun for very few species.
I recommend "Why sex is fun" by Jared Diamond for a fun read... I hope I have remembered correctly (it's been too long since I read it).
>>Even with the help of modern medicine, pregnancy still kills about 800 women every day worldwide
Um..I am not sure about modern medicine part. Most of these women must be in developing countries where you hardly get "modern medicine" on a regular basis.
According to the World Health Organization, 99% of maternal death is in developing countries [0]. Given that this is likely the same source for the 800 women a day stat, the author is probably being willfully ignorant.
I think it is a very important detail to understand that new life has to grow in water.
When life moved out of the water, different life-forms discovered a way to take that environment away from the water to have their embryos grow: Birds keep the water in eggs, mammals in their womb.
While egg-laying animals create self-contained environments, mammals need much more energy to develop therefore have to be live-fed. So they feed this separate, new creature. Of course they have to protect themselves from them.
"We/I thought about everything and this is what we came up with (interwined with very catchy words to hold your attention)"
Could you please do (representative) studies and not assume too much?! Very hurting are some of the cause&conclusion sections... very slim terrain (correlation=/=causation)
Thank you. Yes they are. The doctors were on the ball and pulled baby out as late as they could. Baby is at home fine now and developing normally. She was born at 32 weeks. Because of prenatal steroids her lungs were fully developed.
Preeclampsia, a state of too high blood pressure in the mother, is discussed in the article and is one of the leading reasons for medically induced premature births. However, this in only one of several causes of premature birth. A large number of premature births are spontaneous (starting with either labor or membrane rupture) with no known cause and little forewarning. Infection of the membranes also contributes to a large fraction of premature births. If you are interested in this topic, my lab is looking to hire a database specialist (postgres) in Nashville.
I'm interested in all things biology (tho I have no background in it). What exactly do you need the database specialist to do? what are the problems you are facing?
In my opinion, this is the most interesting paragraph:
>In primates and mice, it’s a different story. Cells from the invading placenta digest their way through the endometrial surface, puncturing the mother’s arteries, swarming inside and remodelling them to suit the foetus. Outside of pregnancy, these arteries are tiny, twisty things spiralling through depths of the uterine wall. The invading placental cells paralyse the vessels so they cannot contract, then pump them full of growth hormones, widening them tenfold to capture more maternal blood. These foetal cells are so invasive that colonies of them often persist in the mother for the rest of her life, having migrated to her liver, brain and other organs. There’s something they rarely tell you about motherhood: it turns women into genetic chimeras.
The whole article sounds so creepy. I never thought you could describe one of the most natural processes in that light.
Although the article dramatizes the conflict, the tug-of-war over resources is real, which probably is why the placenta is one of the fastest evolving mammalian organs in terms of morphology and genetics. The conflict probably shapes the rate of preterm birth quite a bit. If you are interested in this topic, my lab is looking to hire a database specialist (postgres) in Nashville.
Sorry to flog a job opening so shamelessly, but I'm a research scientist at Vanderbilt University working on the evolution of human pregnancy with an emphasis on identifying the causes of preterm birth. We are building a database to integrate a large number of experiments with various evolutionary analyses (with a dollop of machine learning on top), which will soon be available online at genestation.org.
We're looking to hire a full-time database admin/developer who finds biology interesting, but there is no need for formal training in biology.
There’s something they rarely tell you about motherhood: it turns women into genetic chimeras.
I have a genetic disorder and I have given birth to two children, one who has the same disorder and one who does not. In recent months, I have been speculating a bit about the impact those two pregnancies had on my medical condition. So that little snippet was particularly interesting to me because it suggests that having my second child likely left me with little islands of cells which lack my genetic disorder. I already have reason to believe that my pregnancies made me healthier, if only because of the degree to which throwing up for 8 months forced me to eat differently with my first pregnancy and many of those changes in diet became permanent. But this adds some real science to what has mostly been anecdata up until now.
Yes, I was not aware of this difference between primates and other mammals. I had always wondered why pregnancy was so much more of an ordeal for humans. I had previously heard the explanation that our giant brain-filled heads can barely fit through the birth canal, which leading to lots of deaths during delivery, and also explains why we are born with overlapping unfused bone plates in our skulls. But obviously that doesn't account for everything else that can go wrong during pregnancy, so it was always a partial explanation at best. Interestingly, though, both explanations trace back to our species' evolution toward having bigger brains.
For several decades, the simultaneous evolution of the pelvis to support bipedal locomotion and a larger cranium was the leading hypothesis for the selective constraints on birth timing (known as the obstetrical dilemma). Recently, however, a hypothesis that focuses on metabolism and efficient energy transfer from mother to child through the placenta vs feeding has become popular (the EGG hypothesis. Yes, that is the actual acronym from the literature).
Genesis 3:16 also explains it as one of the curses on Adam and Eve: "To the woman also he said: I will multiply thy sorrows, and thy conceptions: in sorrow shalt thou bring forth children..."
> I never thought you could describe one of the most natural processes in that light.
Nature contains the most disgusting things known to man. Most of nature is pretty disgusting in general, especially when observed from up close. Don't fall for the naturalistic fallacy :) [1]
Although the naturalistic fallacy is real, please remember that the foundations of naturalism have some merit, so it's not a universal fallacy. In fact often-times biasing to 'natural' is the best way to get the right outcome.
This article is a great example of my point: Although there is a war going on in the womb that wastes resources, there are some very important side-effects that can only come of that war. The embryo is robustly tested for viability, cancerous growth is averted, and the embryo manages to get more resources. These are difficult goals to achieve any other way.
Other examples abound: Our diet is normally a delicate balance between cravings, metabolism requirements, our gut flora's needs, and so many more factors. Probably a war similar to the womb plays out in our gut, and probably with similar tradeoffs and benefits. The only way to duplicate this complicated machine is to let the battle play its course properly. So the question is, how do we do that? One answer is to look to the environment where this system evolved — in other words to adopt a naturalistic view.
Interference in these systems leads to the balance being upended, and problems developing. We even see this problem with software! When I worked for a large company doing maintenance on very old compilers, we would not interfere in the code too much for fear of triggering one of these imbalances. I think they arise because architects through the years are at war with each-other to impart their 'wisdom'. The result is a carefully orchestrated dance between enemy code, mediated by testcases.
Naturalism captures the idea that we just aren't smart enough to tackle these problems head-on. And even if we were, it might just be cheaper to allow the war to play out instead of duplicating all of its effects. It's only a fallacy because once in a while we are smart enough.
"Disgusting" is subjective. Nature is disgusting from an romanticized anthropocentric perspective, perhaps. The irony is that we owe our and our perspective's existence to nature. Most likely our perspective, having some evolutionary advantage, is a very direct and non-accidental result of the disgusting phenomenon you refer to.
That paragraph also triggered the thought "Are humans biologically wired only to love through conflict?" As a race, can we never be rid of the need to fight one another? Are we fundamentally designed to do so?
This article tugged on my strings in many ways. Philosphically, scientifically, emotionally, artistically. I liked it a lot.
Life is a struggle. I'm edging more and more towards life NEEDING a struggle to reach it's potential. The struggle must be balanced, but it is necessary.
Related but incidental, but what's the deal with Aeon? They don't seem to have a revenue model, but I read and enjoy virtually everything they produce. Is there a gotcha coming?
I don't know either; maybe they're funded by a foundation or somesuch. It's under the umbrella of this magazine content firm: http://magculture.com/projects/
While it tends a bit towards the softer and philosophical end of science, the standard of writing is very high and I've found myself coming back again and again for informative and thought-provoking articles. I would be amenable to paying an annual subscription for it.
It's these kind of articles that cause misunderstandings about how evolution actually works. If we, the HN community, are interested in furthering our knowledge bases, we need to stop falling for these pseudo-intelligent reskinned BuzzFeed articles.