Posted on 12/21/2004 4:13:57 PM PST by beavus
The human parathyroid gland, which regulates the level of calcium in the blood, probably evolved from the gills of fish, according to researchers from King's College London.
Writing in the latest edition of Proceedings of the National Academy of Sciences, Professor Anthony Graham and Dr Masataka Okabe suggest that the gills of ancestral marine creatures, which were used to regulate calcium levels, were internalised rather than lost when land-living, four-limbed animals – the tetrapods – evolved.
Many physiological processes such as muscle contraction, blood coagulation and signalling by nerve cells, require specific levels of calcium in the body. In humans, calcium levels are regulated by the parathyroid gland, which secretes parathyroid hormone if the calcium concentration in the blood falls too low. This hormone then causes the release of calcium from bone, and increases its reuptake in the kidney, raising the calcium levels back to normal.
Fish don't have parathyroid glands. Instead they increase their internal calcium concentration by using their gills to take up calcium from the surrounding water.
'As the tetrapod parathyroid gland and the gills of fish both contribute to the regulation of extracellular calcium levels, it is reasonable to suggest that the parathyroid gland evolved from a transformation of the gills when animals made the transition from the aquatic to the terrestrial environment,' said Professor Graham.
'This interpretation would also explain why the parathyroid gland is positioned in the neck. If the gland had emerged from scratch when tetrapods evolved it could, as an endocrine organ, have been placed anywhere in the body and still exert its effect.'
The researchers supported their theory by carrying out experiments that show that the parathyroid glands of mice and chickens and the gills of zebrafish and dogfish contain many similarities.
Both gills and parathyroid gland develop from the same type of tissue in the embryo, called the pharyngeal pouch endoderm; both structures express a gene called Gcm-2, and both need this gene to develop correctly.
Furthermore, the researchers found a gene for parathyroid hormone in fish, and they discovered that this gene is expressed in the gills.
'The parathyroid gland and the gills of fish are related structures and likely share a common evolutionary history,' said Professor Graham. 'Our work will have great resonance to all those people who have seen Haeckels' pictures, which show that we all go through a fish stage in our development. This new research suggests that in fact, our gills are still sitting in our throats – disguised as our parathyroid glands.'
She probably just had some sort of branchial fistulas or sinuses, and wanted to make the condition sound cool.
Thank you from and x-evolutionist.
I am embarassed to say I once believed this sort of nonsense.
Until Christ turned the light on for me!
This is a myth and was started back in 1890 and was disproven a few years later when the guy who said he ran the experiments admitted he lied about his evidence. Didn't matter to the schools though. They kept right on teaching. Humans embryos never have gills or tails as far as that goes. Proven fact not opinion.
That goes back to Galileo:
Letter to the Grand Duchess Christina of Tuscany. Galileo's opinion about science/scripture conflicts.
It is now the Pope's position: The Pope's 1996 statement on evolution. Excerpt:
It is necessary to determine the proper sense of Scripture, while avoiding any unwarranted interpretations that make it say what it does not intend to say. In order to delineate the field of their own study, the exegete and the theologian must keep informed about the results achieved by the natural sciences.
Shouldn't you know something about the theory of evolution before you ridicule it?
Uh, fish are further back. Apes also have parathyroids, don't they?
HAAA HAAA HAAA HAAA HAAA. Good one....... Hey, wait a minute.... That actually makes sense.
It's a hypothesis, or perhaps the current prevailing theory. What's wrong with that?
"Ontogony recapitulates philogeny"
"Sure, but decent folks don't admit it."
(From one of Keith Laumer's Retief novels...)
A question; the human infant can not fend for itself for many years after birth. Did the parent evolve before the child?
BS
Theory of evolution explains nothing. There is no proof of evolution as a matter of fact all the proof is against evolution which is why evolution was once called darwinism, then went to neo-darwinism and now is called "puntuated equilibrium", better known as the "hopeful monster" theory. These new theories were brought about to explain why there are no transitional species found in the fosil records. I do not know if we were created by God or not, but I do know this after years of study, evolution is not real and has never been proven so. No proof, none. Evolutionists, the scientists, not amatuers, say things like, we know evolution is a fact, we just haven't proven it yet. Now there is a scientific statement if I ever heard one.
I thought these folks would be distracted with destroying christmas creches.
Think of classes, inheritance...
A rather nifty methodology, too bad I don't actually code in Java!
Full Disclosure: If you will permit such a mixed metaphor, there is even room for 'garbage collection'--just look at the Darwin awards; "God taking out the garbage" ;-)!
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