Posted on 05/20/2006 6:02:56 PM PDT by Al Simmons
Fetus' Feet Show Fish, Reptile Vestiges By Jennifer Viegas, Discovery News
May 18, 2006 — The feet of human embryos taking shape in the womb reveal links to prehistoric fish and reptiles, a new study finds.
Human feet may not look reptilian once babies emerge from the womb, but during development the appendages appear similar to prehistoric fish and reptiles. The finding supports the theory that mammalian feet evolved from ancient mammal-like reptiles that, in turn, evolved from fish.
It also suggests that evolution -- whether that of a species over time or the developmental course of a single organism -- follows distinct patterns.
In this case, the evolution of mammalian feet from fish fins to four-legged reptiles to four-limbed mammals to human feet appears to roughly mirror what happens to a maturing human embryo.
"Undoubtedly there are clear parallels between the mammal-like reptilian foot and the human foot," said Albert Isidro, an anthropologist at the Autonomous University of Barcelona, Spain and lead author of the study, which appeared in the journal The Foot.
Isidro and colleague Teresa Vazquez made the determination after analyzing fossils of a number of mammal-like reptiles that lived from 75 to 360 million years ago. The scientists also studied fossils of osteolepiform fish, which appear to be half fish and half reptilian. These fish lived 400 million years ago and had lungs, nostrils and four fins located where limbs would later be found in four-footed reptiles and mammals.
In 33-day-old human embryos, the scientists observed "the outline of a lower extremity in the form of a fin, similar to that seen in osteolepiform fishes." As the embryo continued to develop, the researchers focused their attention on two foot bones: the calcaneous, or heel bone, and the talus, which sits between the heel and the lower leg.
At 54 days of gestation, these two bones sit next to each other as they did within the reptile herbivore Bauria cynops, which lived around 260 million years ago. This ancient reptile had flat, crushing teeth and mammalian features.
At eight and a half weeks of gestation, the researchers found the two embryonic foot bones resemble those seen in the Diademodon vegetarian dinosaur, which lived around 230 million years ago.
"We can tell that the embryo is half way between the reptiles and the mammals (at this stage)," Isidro told Discovery News.
The two foot bones continue to develop until, at nine weeks, they resemble that of placental mammals as they emerged 80 million years ago.
This development of feet in the human embryo mirrors how the foot evolved over millions of years beginning with fish and ending with early mammals, according to the scientists.
Supporting the fish/foot link was the discovery last month of a new species, Tiktaalik roseae, which lived 375 million years ago. It had fish fins and scales, but also limb parts found in four-legged animals.
"Tiktaalik blurs the boundary between fish and land-living animals both in terms of its anatomy and its way of life," said Neil Shubin, professor and chairman of organismal biology at the University of Chicago and co-author of a related paper in the journal Nature.
H. Richard Lane, director of sedimentary geology and paleobiology at the National Science Foundation, said, "These exciting discoveries are providing fossil ‘Rosetta Stones’ for a deeper understanding of this evolutionary milestone: fish to land-roaming tetrapods (four limbed animals)."
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It's pretty sad that some people have been indoctrinated to the point where any observations in ontogeny is immediately connected to Haeckel and thus a "fraud".
Where have they been proven lies? I've seen the claim many times here on FR, but never been shown the evidence.
Right. And you can look at human fetuses and chicken embryos and at a certain early stage they look just alike. That should mean we came from chickens?
Just how new is this study? I'm sure I read about this 20 years ago.
Also when human babies are born they all look like E.T., so maybe this validates the scientology crowd's beliefs too.
"Also when human babies are born they all look like E.T...."
They do? Can you provide any pictures to validate this claim? I have never sen a baby that looked anything like ET.
So you say. And yet, you have absolutely nothing to back up your contention. Go figure.
A SET of 19th-century drawings that still appear in reference books such as Gray's Anatomy are badly misdrawn, says an embryologist in Britain.German naturalist Ernst Haeckel published the drawings 123 years ago in support of his famous dictum "ontogeny recapitulates phylogeny". They appear to demonstrate that the young embryos of fish, birds and humans look nearly the same. "He's shown the similarity, but he hasn't shown the differences," says Michael Richardson of St George's Hospital Medical School in London.
Richardson and his colleagues compared the embryos of 50 vertebrates to Haeckel's drawings. They say in Anatomy and Embryology (vol 196, p 91) that Haeckel left out some features, such as the budding limbs that some embryos have, while adding others, such as an excess of vertebra-like "somites".
Although Haeckel confessed to drawing from memory and was convicted of fraud at the University of Jena, the drawings persist. "That's the real mystery," says Richardson.
I cracked open a chicken egg this morning and found a bright orange sphere. Obviously chickens evolved from oranges.
ROFLMAO, that's exactly what I was thinking.
The simplest solution is the design engineers at the "mammal feet" factory came up with this one because it was more economical, easier, superior to other methods, or they didn't wrap up the job as well as they thought they did.
Aw, How cute!!! ......
Or... it could be evolution at it's best. ;)
I think one big reason the evolutionists are so unpopular is that they display such repulsive personalities--a throwback to the wolves from whom they are descended, perhaps?
In any case, I have no quarrel with the general theory of evolution, but I think it's worth noting that the "ontology recapitulates phylogeny" theory has been supported with a whole lot of wishful thinking as well as willful fraud. I cannot help but wonder if the present "study" has included one or the other.
can't argue with that logic.
Here's a problem ~ until we can replicate the supposed "evolutionary process" at will, or invent a time machine so we can observe it with certainty, we really don't have proof ~ just an idea.
Same goes for the DNA factory ~ although I think there's a tad more hope of finding it than of demonstrating evolution in a controlled experiment.
You come in with an absolutely painful logical fallacy, and no one was supposed to notice? Anyone who would see such a thing is repulsive for noticing bad things about your reasoning?
In any case, I have no quarrel with the general theory of evolution...
If your arguments against it were more honest, I would have less problem believing you here.
... the "ontology recapitulates phylogeny" theory has been supported with a whole lot of wishful thinking as well as willful fraud.
This is a modern study with modern instruments. For more of the same, click here.
One set of drawings from the 19th century is a fraud. We have other drawings and we have plenty of real-life photographs now.
All embryos have throwbacks to their evolutionary history. This is entirely different from saying that mammals actually -become- reptiles at one point in their development.
Interesting book.
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