Fetus' Feet Do NOT Show Fish, Reptile Vestiges

Dianne N. Irving
Copyright May 26, 2006
Reproduced with Permission

The article from the Discovery Channel below represents a continuing, but useless, attempt to bolster the sagging reputation of the ole "biogenetics law" myth -- currently used in several international human cloning and human embryonic stem cell laws (e.g., the Canadian CIRMS Guidelines for Stem Cell Research). It is often used as the basis for "proving" Darwin's theory of evolution. Pity that journalists and especially scientists are not required to take a course in human embryology before they graduate ... and pontificate. Think of all the fake "science" our students are going to have to unlearn in the years to come; and hopefully they won't use this and related fake "science" as integral parts of their future scientific/medical research protocols or clinical trials! The article attempts to correlate the "evolving" shape of developing human fetuses in utero with "reptile vestiges" of non-human species in millennia gone by -- while developing in the womb! It is worth noting the recent caustic rebuttal of the "biogenetics law" by Swiss human embryologists Ronan O'Rahilly and Fabiola Muller (2001):

"Recapitulation, the So-Called Biogenetic Law. The theory that successive stages of individual development (ontogeny) correspond with ('recapitulate') successive adult ancestors in the line of evolutionary descent (phylogeny) became popular in the nineteenth century as the so-called biogenetic law. This theory of recapitulation, however, has had a 'regrettable influence on the progress of embryology' (G. de Beer). ... According to the 'laws' of von Baer, general characters (e.g., brain, notochord) appear in development earlier than special characters (e.g., limbs, hair). Furthermore, during its development an animal departs more and more from the form of other animals. Indeed, the early stages in the development of an animal are not like the adult stages of other forms but resemble only the early stages of those animals. The pharyngeal clefts of vertebrate embryos, for example, are neither gills nor slits. Although a fish elaborates this region into gill slits, in reptiles, birds, and mammals it is converted into such structures as the tonsils and the thymus." [Human Embryology & Teratology (3rd ed.)(New York: Wiley-Liss, 2001), p. 16)]

Note that O'Rahilly was one of the original creators of The Carnegie Stages of Early Human Development, and has sat on the international nomenclature committee for human embryology for decades.


The Discovery Channel

By Jennifer Viegas, Discovery News

Fetus' Feet Show Fish, Reptile Vestiges

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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