Friday, October 9, 2009
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11 comments:
fascinating- thanks for posting this!
Amazing... thank you.
How come we don't see an umbilical cord and a placenta?
A couple of times in the video, the narrator said that the elephant mom knows what she's doing. This got me thinking. Most animals give birth successfully without any intervention. When most human moms give birth, they don't know what the heck they're doing. Without a doctor, who knows how many babies would die. From an evolutionary perspective, why don't humans have this advantageous faculty of "knowing what to do when having a baby"?
Alex,
It's a fascinating story. The baby's head is very large relative to the mother's cervix (and even so much of the brain's development must occur after birth) and needs to do a perpendicular twist to get into the birth canal. This necessitates a tight squeeze and the need, across all cultures, to seek assistance. Even so, death in childbirth was commonplace until the advent of modern obstetrics. There is an interesting article on it in a special issue of Scientific American:
Click here
As Dobzhansky said, nothing in biology makes sense except in the light of evolution.
Oh my...messy miracles.
fantastic-- nothing squeamish about it. totally amazing. really very beautiful film.
Neandershort, it seems like you're saying that a mom who needs assistance in giving birth is evolutionary advantageous to one who does not. (Am I interpreting you incorrectly?) This goes against (my) common sense.
PS, I'm not so sure about Dobzhansky's grandiose claim. A.S. Wilkins, a leading evolutionary biologist, writes: "The subject of evolution occupies a special, and paradoxical, place within biology as a whole," he wrote. "While the great majority of biologists would probably agree with Theodosius Dobzhansky's dictum that 'nothing in biology makes sense except in the light of evolution,' most can conduct their work quite happily without particular reference to evolutionary ideas. Evolution would appear to be the indispensable unifying idea and, at the same time, a highly superfluous one." - BioEssays, December(2000)
Alex: There is, in fact, a theory that human society is due to the helplessness of babies.
Pogomel - Did you read the Sci Am article? Nature does not have the luxury (as a putative "intelligent designer" would) of starting from scratch. It must work with "facts on the ground." Large brains necessitate a tight fit of head to pelvis, which creates difficulty giving birth. Given that constraint, seeking assistance increases the likelihood of a positive outcome, i.e. a healthy mother and baby. Most mothers don't need assistance; they can be tied to a tree and would give birth safely if uncomfortably, but since we are a social species and seeking assistance at birth is possible, it is advantageous to do so. By the way, the upshot of all this is that difficult childbirth is the price we pay for being intelligent animals - not too far from the account in Parshat Bereshit. And until recently it was a high price indeed.
As for evolution being a superfluous theory, engineers, including practicing physicians, can go about their business without making reference to the underlying theory that makes their work possible. It would be difficult to imagine a working scientist, one engaged in creating new knowledge, not referring back to his/her discipline's basic theories. As a teacher, I know that without evolution biology is little more than a set of disjointed facts that students have to memorize. Evolution gives my students the "big picture." It is the tie that binds all the disparate parts of the course and makes it a coherent, internally consistent, intellectually satisfying and supremely fascinating whole. In my course evolution is not merely one of many units of study, and it is a rare day in my class when I do NOT make some mention of it.
There are theories for just about everything that goes against common sense, so I'd like to see more than just a theory offered.
Ah, "just a theory." You don't understand what a scientific theory is and what scientists mean when they dignify a statement by calling it a theory. It's sad but not surprising - they don't teach science in most yeshivot. A theory is not a hunch or conjecture. It's a construct that explains a large body of data and generates testable predictions. Gravitation and electromagnetism are "just theories." And in biology, there is no theory that explains the data better than evolution. Indeed, evolution is the only theory that comes under the heading of science; supernatural explanations do not.
Many statements in science and math are counterintuitive, i.e. they "go against common sense." But when rigorous proofs are offered (the theorems we studied in geometry) and data are marshalled, they become clear. And if we are lucky, we can devise an overarching theory to explain them.
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