Computer simulations show human ancestors would have had an easier time giving birth than modern women

Computer simulations show human ancestors would have had an easier time giving birth than modern women
Ellipse representing a neonatal A. sediba head at the pelvic. A. inlet, frontal view B. inlet, superior view C. midplane, superior view. Reconstructed pelvis is shown with the MH1 ischium. Notice that the modeled A. sediba neonatal cranium can descend into the midplane without bony constraints, unlike the condition typically found in modern humans. Credit: PLOS ONE (2019). DOI: 10.1371/journal.pone.0221871

A trio of researchers with Boston University and Dartmouth College has found that one of our ancient ancestors likely had a much easier time giving birth than modern humans. In their paper published on the open-access site PLOS ONE, Natalie Laudicina, Frankee Rodriguez and Jeremy DeSilva describe how they created 3-D computer models of some of our ancient ancestors and compared them with modern humans and chimpanzees—and describe what they found.

For many women, childbirth is a long, painful and difficult process. Prior research has suggested the reason childbirth is so much more difficult in humans compared to apes or other animals is because we evolved to walk upright, and because our have very large heads. As humans developed an upright gait, our pelvises changed in ways that made the narrower. During birth, a modern human baby must turn in the womb several times as it is pushed through the birth canal by the pelvic muscles.

In sharp contrast, chimpanzees give birth in short order and appear to experience very little pain. In this new effort, the researchers wondered about the birth experience for one of our ancestors, Australopithecus sediba—a hominin that lived approximately 1.95 million years ago. To find out, they created a 3-D representation of an A. sediba pelvis using imagery from several fossils. While they were at it, they also created 3-D representations of Australopithecus afarensis and Homo erectus. And for additional comparison, they also created 3-D images of a modern human and a chimpanzee pelvis. To study the degree of difficulty of giving birth, the researchers also added baby human skull-sized objects to the 3-D images as they would normally sit in the birth canal.

The researchers report that the size of the A. sediba birth canal was quite large compared to the size of the skull of the baby that would need to pass through it. They suggest this indicates that compared to modern women, A. sediba would have had a much easier time giving birth. The researchers also note that contrary to popular belief, the evolution of the canal was not a clearly defined path from big to small—prior research has shown that an earlier ancestor, Lucy, (Australopithecus afarensis) likely had a difficult childbirth.


Explore further

'You will give birth in pain': Neanderthals too

More information: Natalie M. Laudicina et al. Reconstructing birth in Australopithecus sediba, PLOS ONE (2019). DOI: 10.1371/journal.pone.0221871
Journal information: PLoS ONE

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Sep 21, 2019
Looks like drift under the constraint that our social lineage could survive the sometimes painful result.

Now that we walk upright, the birth canal could exit the lower abdomen above the pelvis. Like the overly long laryngeal nerve in giraffes, our overly complicated birth process is evidence for the blind process of evolution.

Sep 21, 2019
There is another study out there showing that womens daughters who have a caesareans have a much higher rate of needing them....wondering if modern medicine will actually be the end of us. Are these things going to drive us to a handmaids tail type of world where very few women can actually survive birth?

Sep 21, 2019
@overcurious:

That is not evolution though, such stuff is easily drowned out against the large population.

In any case, our problematic alleles are often many and recessive, we live with them and we survive their effects. But I don't understand why you are telling us about your obsession with your (?) handmaid's tail, maybe you should date him or her instead!? (Just pulling your leg, I think there is a series called Handmaid's Tale, are you referring to it? And here I thought it was about authoritarian, misogynistic societies - a mirror of current US.)

Sep 21, 2019
.. our overly complicated birth process is evidence for the blind process of evolution.

Well, oh sighted one, please enlighten us, as to what our uncomplicated birth process, would be?

Sep 22, 2019
Weston Price, a well know Dentist who did extensive research on world wide dietary patterns world wide and wrote a book about it, discovered that cultures with poor nutriton often had certain patterns in their skelatal growth that proved identical world wide. He was of course concerned with peoples mouths more than their birth canals, but it seems plausible that his discoveries also applied to other skelatal growth areas like birth canals.

In short he discovered that malnourished people of all races often had narrow faces and mouths without room for wisdom teeth, unlike the round faces and perfect mouth structures of the ones with healthier diets. It also was discovered that the narrow faces and small mouths were also usually accompanied with malaligned rotting teeth. He hypothesized that the people with the narrow faces and narrow skeletal development were missing certain essential human nutrients that humans normally got from eating mostly animals or fish.


Sep 22, 2019
I thus hypothesize that the birth canal size had more to do with nutrition than it does with age of skeleton.

P.S. this second post was much longer but apparently I hit a wrong key and lost it right before it was finished. It involved much more evidence of my hypothesis but i am out of time.

Sep 22, 2019
Price's book is titled: "Nutrition and Physical Degeneration". The book of course, like all inferences from population surveys or skeletal remains, is not proof, but it is a very convincing hypothesis. If you read it or even just look at its ample photographic comparison evidence you too will be persuaded.

Sep 23, 2019
Sorry, this can be explained by the introduction of the African species on Earth. The discrepancy due to accumulated deviations toward pain to appease the inverted relation between Human and African internal states, the more pain during the threatening act of producing one new Human, the less chances Africans will affect the survivability of the newborn. We let them attack all aspects of Human procreation, toward nullification (less romance, less love, less wooing, less family life, less naturality, less beauty, less lust, reduced sexual life, less pleasure, less sexual freedom, masochism and sadism, ...), but conception itself is enough to protect to minimize their negative impact on Human population growth. Of course, the explanation is biomechanical according to thermodynamics.

Sep 23, 2019
This is part of why i think aliens were involved in human evolution. Modern man has become an invasive species. We can barely reproduce without technology's help. We just dont fit with this planet anymore.

Sep 23, 2019
Sorry, this can be explained by the introduction of the African species on Earth. The discrepancy due to accumulated deviations toward pain to appease the inverted relation between Human and African internal states, the more pain during the threatening act of producing one new Human, the less chances Africans will affect the survivability of the newborn. We let them attack all aspects of Human procreation, toward nullification (less romance, less love, less wooing, less family life, less naturality, less beauty, less lust, reduced sexual life, less pleasure, less sexual freedom, masochism and sadism, ...), but conception itself is enough to protect to minimize their negative impact on Human population growth. Of course, the explanation is biomechanical according to thermodynamics.
Just out of curiosity, where do you think 'humans' evolved? Do you have any sources? Assuming your not just a smelly little troll that is-

Sep 23, 2019
Who let the crackpots in?

@Anonym: Never heard of Price, but his theories are controversial and not useful [ https://en.wikipe...on_Price ]. "Focal infection theory fell out of favor in the 1930s and was pushed to the margins of dentistry by the 1950s.[6] By 1930, Price had shifted his interest to nutrition. ... This work received mixed reviews, and continues to be cited today by proponents of many different theories, including controversial dental and nutritional theories."

So no, nobody scientifically literate and few able to make a simple web search will be "persuaded". Humans are more disparate in faces than other apes, it is suspected by biologists to ease social recognition.

And I will be generous and for the time being assume you are not racist, despite mentioning 'races' and being obsessed with facial features when the subject was the pelvis/birth canal.

Sep 23, 2019
Here on the other hand we have a full blown racist:

the inverted relation between Human and African


Existing humans *are* Africans, to 90+ %, only a few percent remaining alleles or genes are European-Asian Neanderthal/Denisovan humans, using their source regions for labeling. Humans (Homo) have been the related lineages labeling covering the last 3.5 million years.

But I suspect you are referring to erroneous racist concepts rather than factual populations.

Blocked for inane, unreadable trolling.

***

And I am not going to bother with the UFO/extinction conspiracy theorist, too boring. Except blocking for inane trolling, of course.

Sep 24, 2019
The info you want seems to be in updated book _The Seven Daughters of Europe_. Africans are celebrating they just destroyed one of them or are very near it. I would say this Larsson above is an Undyed African so he naturally sells Human as 90% African, given Asians are gods to them and recognizing Arabs and Indians are kin; the substitution which I ve seen in process of course eliminates a good number of non Africans impersonated or defrauded by sheer coloration. The study does not seem to add much knowledge but only confirms what we already knew. Africans do exhibit very diminished sensorial perception regarding pain compared to (non schizophrenic) Humans.

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