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evolution-digest Saturday, February 6 1999 Volume 01 : Number 1283

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Date: Fri, 5 Feb 1999 16:13:58 -0700
From: "Dr. M Murphy" <mmurphy@cintek.com>
Subject: Human birth

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I recently posted my first posting to the site with some info about =
myself - so far without response. Anyway, I am in the process of =
writing a book on the human pelvic floor and how that relates to the =
birth process. Naturally, the erect position of humans and the effect =
of that on the pelvis and birth would come into it.
I now want to take the liberty to attach a few paragraphs dealing with =
this issue and to request a critique from a factual point of view. Any =
suggestions will be welcome.

Thanks in advance.

Magnus Murphy

The pelvic floor is an evolutionary newcomer:

The earliest fossil records of a hominid bipedal (human-like and walking =
upright), can be dated to about 3.5 million years ago. These species, =
called Australopithecines, had an almost human-shaped pelvis, but had a =
much smaller brain capacity. There are numerous theories trying to =
explain the evolutionary benefit of an erect posture that ultimately led =
to hominid species becoming the dominant species on the planet. To me =
the most logical theory is that the freeing of the hands for purposeful =
manipulation of tools provided an increased ability to defend itself and =
to acquire food. These factors could have led to an increased =
evolutionary fitness in terms of competition with other species.

Various evolutionary processes, and especially the development of =
speech, theoretically led to a massive increase in brain capacity. This =
increase in brain capacity is well documented in the fossil records with =
a direct line that can be drawn from Australopithecus, through Homo =
habilis and Homo erectus and Homo sapiens. It is currently believed that =
Homo sapiens and another species called Homo Neanderthalensis actually =
coexisted for a long period of time and until as recently as 30,000 =
years ago. It is believed that the two species did not interbreed and =
that Neanderthalensis might have become extinct as a result of direct =
competition with Homo sapiens.

One theory that tries to explain the increased evolutionary fitness of =
Homo sapiens is the development of speech, that made communication and =
thus the development of culture possible. The development of speech led =
to a massive increase in certain parts of the brain, particularly the =
frontal and temporal lobes, with the end result a brain that is often =
over 2000 cc in size.

The large brain size obviously creates problems for the birthing process =
since the fetus survives best if it is large, but with obvious =
consequences for the mother. The birthing process can be likened to a =
competitive interaction between the mother and her fetus, with some =
common ideals (for instance the survival of both), but also some =
divergent goals; to personally come from the experience in as good a =
shape as possible.

Recent evidence from scientific studies has indicated the possibility =
that the pregnant mother can directly influence the size of her unborn =
fetus, especially towards the end of her pregnancy. It has apparently =
been shown that this observation holds true even in the setting of donor =
embryos from large genetic parents into smaller surrogate mothers, with =
resultant smaller infants that would have been suspected. The =
theoretical way the birth mother can accomplish this is by restricting =
the bloodflow to her uterus and thus the availability of nutrients to =
the fetus.

This finding may be evidence of an attempt of the mother to protect her =
own interests to the general detriment of the fetus. Of course it should =
be self-evident that if there were an insurmountable discrepancy between =
the pelvis of the mother and the size of the fetus, it would also be to =
the clear disadvantage of the infant.

Evolutionary theory has some further solutions for the problem of =
"reproductively unfit" individuals as a result of too small pelvises, =
since mothers with pelvises too small to give birth would die during =
childbirth and thus not propagate their (and their partner=92s) genes =
(the baby would almost always die as well). The other side of the coin =
is that the inability of babies with increasing brain size to be born =
alive, was theoretically an inhibiting factor in further evolutionary =
brain size development.

These theories raise as many questions as answers of course, not least =
of which is where Orthodox religious views come in. Evolutionary theory =
is just that =96 a theory trying to explain what is seen in nature and =
known from science. This theory has not however been proven and a =
"Creationist" view of the origin of life is just as valid. My own =
personal view is a combination of "creation through (some aspects of) =
evolution". Whatever view one holds however, one cannot escape the fact =
that the delivery of a healthy infant without significant damage to the =
mother, is a high stakes competitive situation where things can (and do) =
go wrong.

Our ability to deliver babies safely by cesarean section in cases of =
obstructed labor has revolutionized our ability to intervene in nature =
(whether that should be read "evolutionary" or "Divinely" created). This =
ability has not only removed the necessity for an adequate pelvis, but =
also the impediment to possible evolutionary brain-size development.

The upright posture of humans brings with it a number of other problems =
as well. When we look around the animal kingdom, we find in most mammals =
that the pelvic " floor" is not a floor at all, but a wall. Since the =
usual primate posture is for the body to be horizontal, the brunt of the =
intra-abdominal weight does not fall on this structure at all, but =
rather onto the anterior abdominal wall. In the human the pelvic floor =
became the most important support structure for pelvic and abdominal =
contents. The full force of gravity has to be counteracted by the pelvic =
floor and with weak pelvic floor muscles, the fascial layers (to be =
discussed later in detail) are the last defense against prolapse.

In the global scheme of things, the integrity of pelvic floor over time =
is after all not all that important. Nature couldn't care less if your =
bottom fell out at age 50. The most important biological functions =
ensuring the survival of our species (reproduction) have long been =
completed at this age. During most of human existence people furthermore =
rarely made it to this age. Fortunately this has changed in a big way. =
It becomes imperative to us to look with new eyes at this problem and to =
develop new strategies to protect those parts of our bodies less likely =
to stand the test of time and aging.

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I recently posted my first posting =to the site=20with some info about myself - so far without response.  Anyway, I =am in the=20process of writing a book on the human pelvic floor and how that relates =to the=20birth process.  Naturally, the erect position of humans and the =effect of=20that on the pelvis and birth would come into it.
I now want to take the liberty to attach a few =paragraphs=20dealing with this issue and to request a critique from a factual point =of=20view.  Any suggestions will be welcome.
 
Thanks in advance.
 
Magnus Murphy
 
 

The pelvic floor is an evolutionary newcomer:

The earliest fossil records of a hominid bipedal (human-like and =walking=20upright), can be dated to about 3.5 million years ago. These species, =called=20Australopithecines, had an almost human-shaped pelvis, but had a much =smaller=20brain capacity. There are numerous theories trying to explain the =evolutionary=20benefit of an erect posture that ultimately led to hominid species =becoming the=20dominant species on the planet. To me the most logical theory is that =the=20freeing of the hands for purposeful manipulation of tools provided an =increased=20ability to defend itself and to acquire food. These factors could have =led to an=20increased evolutionary fitness in terms of competition with other =species.

Various evolutionary processes, and especially the development of =speech,=20theoretically led to a massive increase in brain capacity. This increase =in=20brain capacity is well documented in the fossil records with a direct =line that=20can be drawn from Australopithecus, through Homo habilis and Homo =erectus and=20Homo sapiens. It is currently believed that Homo sapiens and another =species=20called Homo Neanderthalensis actually coexisted for a long period of =time and=20until as recently as 30,000 years ago. It is believed that the two =species did=20not interbreed and that Neanderthalensis might have become extinct as a =result=20of direct competition with Homo sapiens.

One theory that tries to explain the increased evolutionary fitness =of Homo=20sapiens is the development of speech, that made communication and thus =the=20development of culture possible. The development of speech led to a =massive=20increase in certain parts of the brain, particularly the frontal and =temporal=20lobes, with the end result a brain that is often over 2000 cc in =size.

The large brain size obviously creates problems for the birthing =process=20since the fetus survives best if it is large, but with obvious =consequences for=20the mother. The birthing process can be likened to a competitive =interaction=20between the mother and her fetus, with some common ideals (for instance =the=20survival of both), but also some divergent goals; to personally come =from the=20experience in as good a shape as possible.

Recent evidence from scientific studies has indicated the possibility =that=20the pregnant mother can directly influence the size of her unborn fetus, =especially towards the end of her pregnancy. It has apparently been =shown that=20this observation holds true even in the setting of donor embryos from =large=20genetic parents into smaller surrogate mothers, with resultant smaller =infants=20that would have been suspected. The theoretical way the birth mother can =accomplish this is by restricting the bloodflow to her uterus and thus =the=20availability of nutrients to the fetus.

This finding may be evidence of an attempt of the mother to protect =her own=20interests to the general detriment of the fetus. Of course it should be=20self-evident that if there were an insurmountable discrepancy between =the pelvis=20of the mother and the size of the fetus, it would also be to the clear=20disadvantage of the infant.

Evolutionary theory has some further solutions for the problem of=20"reproductively unfit" individuals as a result of too small =pelvises,=20since mothers with pelvises too small to give birth would die during =childbirth=20and thus not propagate their (and their partner’s) genes (the baby =would=20almost always die as well). The other side of the coin is that the =inability of=20babies with increasing brain size to be born alive, was theoretically an =inhibiting factor in further evolutionary brain size development.

These theories raise as many questions as answers of course, not =least of=20which is where Orthodox religious views come in. Evolutionary theory is =just=20that – a theory trying to explain what is seen in nature and known =from=20science. This theory has not however been proven and a ="Creationist"=20view of the origin of life is just as valid. My own personal view is a=20combination of "creation through (some aspects of) evolution". =Whatever view one holds however, one cannot escape the fact that the =delivery of=20a healthy infant without significant damage to the mother, is a high =stakes=20competitive situation where things can (and do) go wrong.

Our ability to deliver babies safely by cesarean section in cases of=20obstructed labor has revolutionized our ability to intervene in nature =(whether=20that should be read "evolutionary" or "Divinely" =created).=20This ability has not only removed the necessity for an adequate pelvis, =but also=20the impediment to possible evolutionary brain-size development.

The upright posture of humans brings with it a number of other =problems as=20well. When we look around the animal kingdom, we find in most mammals =that the=20pelvic " floor" is not a floor at all, but a wall. Since the =usual=20primate posture is for the body to be horizontal, the brunt of the=20intra-abdominal weight does not fall on this structure at all, but =rather onto=20the anterior abdominal wall. In the human the pelvic floor became the =most=20important support structure for pelvic and abdominal contents. The full =force of=20gravity has to be counteracted by the pelvic floor and with weak pelvic =floor=20muscles, the fascial layers (to be discussed later in detail) are the =last=20defense against prolapse.

In the global scheme of things, the integrity of pelvic floor over =time is=20after all not all that important. Nature couldn't care less if your =bottom fell=20out at age 50. The most important biological functions ensuring the =survival of=20our species (reproduction) have long been completed at this age. During =most of=20human existence people furthermore rarely made it to this age. =Fortunately this=20has changed in a big way. It becomes imperative to us to look with new =eyes at=20this problem and to develop new strategies to protect those parts of our =bodies=20less likely to stand the test of time and=20aging.

- ------=_NextPart_000_000E_01BE5122.894FD140--------------------------------Date: Fri, 5 Feb 1999 17:46:53 -0600From: "Karen G. Jensen" Subject: Re: Early Cambrian explosionAt 12:37:03 -0500 on 5 Feb 1999 Steve Schimmrich" wrote,> You seem to be arguing for a divine creative event at the base of the>Cambrian for metazoans. Now you know that metazoans appear in the late>Proterozoic as well (i.e. they don't all occur instantly in the geologic>record just, geologically-speaking, very quickly). How is this explained?Maybe Art wouldn't mind if I say something here.Time of origin and time of burial are two distinct things. Evolutionarypaleontologists may equate first fossil appearance with origin, butcreation - flood paleontologists are more aware of the difference betweenthese two events.There is no need for multiple steps of creation.The base of the Cambrian records the first massive burial of abundantseafloor life (that is the death of these organisms) but their origin (andtheir life) necessarily precedes their time of burial. In a creation-floodmodel, Proterozoic bacteria and upper Proterozoic metazoans, as well asCambrian forms, lived contemporaneously after the origin of multicellular(and unicellular) life, before the initiation of the large scale burialevents that resulted in the Phanerozoic blanket of sediment layersworldwide.The Precambrian forms, perhaps having burrowed into the seafloor sediments(before any Phanerozoic layers were deposited), were trapped in placed andfossilized when the Cambrian sediments flowed in above them. Thefossilization of both Cambrian and Precambrian forms thus occurred more orless simultaneously.There is a time-gap between creation and fossilization, but not betweenPrecambrian and Cambrian (and most Phanerozoic) fossilization.The "Cambrian Explosion", instead of being explosive diversification, isexplosive sedimentation.>When do you date this creative event?Clearly before the Cambrian Explosion event, but not at any specificPrecambrian horizon. And not with implicit faith in the methods of datingPrecambrian layers. Secondly, unicellular organisms are>themselves pretty complex on the cellular level and their record extends back>into the Archean.Yes! This is a major point! They have complex biochemistry, the origin ofwhich points to... well, that gets into an ID discussion....Again, their lower stratigraphic position of entombment does notnecessarily prove an earlier date of origin, life, or death. How many creative events are you postulating? One? Two?>A dozen?One. After a while, progressive creationism tends to start looking like>evolutionary speciation.>Progressive Creationism has problems both biblically and scientifically.> Let's assume that metazoans were miraculously created at the PC/C boundary.>How on Earth does one test that hypothesis? I would assume by trying to>falsify>it by searching for earlier metazoan fossils. Isn't that what paleontologists>are doing (although, admittedly, not with those motives) since the>development of>metazoan life is a hot research topic right now.A few may have been found. That is OK with the concept of contemporaneityof life, and essential simultaneity of burial/fossilization. And how do we know when we've>searched long and hard enough to conclude that maybe your idea is correct?We don't know for sure. Just look at the abundance of data, and where itpoints. The>problem with your hypothesis (and generally all "theistic science" type>hypotheses)>is that they seem, at least to me, to be untestable.>Well, we have a lot of data out there, and it accords with the hypothesis.The major issue in testing it is determining how fast and deep the Cambrianand other Phanerozoic sediments came in. Clearly it was fast and deepenough in many areas to exclude much bioturbation. Also in some areasexcluding diffusion of oxygen (stopping decay and enabling considerabledetailed preservation). And geologically, there is abundant evidence ofrapid sedimentation.Let's see what Art says.Karen------------------------------Date: Fri, 05 Feb 1999 20:43:59 -0500From: Ed Brayton Subject: Re: Early Cambrian explosion"Karen G. Jensen" wrote:> There is no need for multiple steps of creation.>> The base of the Cambrian records the first massive burial of abundant> seafloor life (that is the death of these organisms) but their origin (and> their life) necessarily precedes their time of burial. In a creation-flood> model, Proterozoic bacteria and upper Proterozoic metazoans, as well as> Cambrian forms, lived contemporaneously after the origin of multicellular> (and unicellular) life, before the initiation of the large scale burial> events that resulted in the Phanerozoic blanket of sediment layers> worldwide.>> The Precambrian forms, perhaps having burrowed into the seafloor sediments> (before any Phanerozoic layers were deposited), were trapped in placed and> fossilized when the Cambrian sediments flowed in above them. The> fossilization of both Cambrian and Precambrian forms thus occurred more or> less simultaneously.>> There is a time-gap between creation and fossilization, but not between> Precambrian and Cambrian (and most Phanerozoic) fossilization.>> The "Cambrian Explosion", instead of being explosive diversification, is> explosive sedimentation.This may work for phanerozoic bacteria, proterozoic metazoans and the earlyCambrian fauna, but how does it work for the entire order of successionalappearance? Is it your position that all of the forms of vertebrates, from fish tomammals, were also created at the same time and just didn't manage to leave behinda trace until hundreds of mlllions of years later? How can this be explained fromyour perspective without multiple creation events?Ed------------------------------End of evolution-digest V1 #1283********************************