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.'
"In the womb, for a short time, we all have gills."
I don't think so.
No, they got stuck at the "snake" stage.
The above is a perfect example of how inverted and warped evolutionists arguments have become.
As if Christianity has NOTHING to do with the Christ of the Bible, Genesis and testimony of God's creation.
Read what your great "father" of evolution believed;
In his own autobiography, Darwin admitted that his evolutionary beliefs gradually made the Bible unbelievable to him and said "Thus disbelief crept over me at a very slow rate, but was at last complete. The rate was so slow that I felt no distress, and have never since doubted even for a single second that my conclusion was correct. I can indeed hardly see how anyone ought to wish Christianity to be true."
psst, you obviously didn't follow the link :-)
Well, after the phenomenon of cold water "shrinkage," the "peanut family" is about the score!
The question was why it wouldn't evolve to NOT fit. I think it's a valid question, but it does have an explanation. The answer lies in the population ratio of prey to predator. A deer's adaptive advantages are more efficiently geared differently from the predator's, whose survival of species is more tied to its capture of prey than its reproductive or other functions, unlike the deer.
Because the deer would survive, and then could reproduce and pass on its genes. Seems self-evident to me.
there=their, sorry, I hate the wrong there/their being used, should have proof read.
No. Just pick one of those creationist web-sites. Much more informative and easier to read than the Bible.
Gives new meaning to the term, " he drinks like a fish "
Thanks for the ping!
"Somebody explain to me how "probably" or "resonable to suggest" and "many similarities" constitute scientific evidence that human beings evolved from FISH!"
Scientific evidence is never certain. Scientific theories are never perfect. This is the nature of science. Newton's law of gravity was pretty darn good for hundreds of years but Einstien came along and found something that Newton missed and improved the equations a bit. Certainly someone else will come along and do the same with Einstien's equations. Same thing is true with the various theories explaining how life and mankind came to be. Just because science cannot make the leap from complete ignorance to a perfect a theory without misteps and approximations along the way doesn't mean that it is not a very useful way of trying to understand our world. God gave us our brains, we should never be afraid to use them. God isn't afraid of truth, why should we be?
Having said that I doubt it is possible to pass judegement, one way or the other, regarding the strength of the scientific evidence of the theory under discussion by just reading a short newspaper article. In any case, I didn't get the impression from the article that the researchers were making over-the-top statements about the strength of their evidence so therefore I don't really see the problem.
"Does not apply. No American mother could exist without first being an American infant. No American infant could exist without having a American mother to care for it for years after birth. See the dilemna?"
Question: Was George Washington's mother an American?
"Does not apply. No French Poodle mother could exist without first being a French poodle puppy. No French Poodle puppy could exist without having a French Poodle to care for it for years after birth. See the dilemna?"
Question: When Christ was born, were there any French Poodles"?
Each infant or puppy or kitten or colt or fruit fly or bacterium is NOT an exact carbon copy of its mother.
If they were, we would not have to worry about antibiotic-resistant bacteria and the U.S. Navy would not have to deal with ship rats that are resistant to rat poison.
Offspring change. And their children change. And their grandchildren change. And their great-grand-children change. And their great-great-grand-children change. And on and on and on...............
See the process?
You don't speak English, eh? ;-)
It's funny how evos seem to think that creatures change through some kind of will of their own. I really think that you have to read this into their thought processes.
I have to constantly remind myself and others of this when talking to laymen, who might take the shorthand literally. When I say that a "stream looks for the most direct channel," I don't mean it has eyes. Likewise, evolution isn't consciously directed, but it can seem that way in hindsight because of the winnowing process.
In other words, you're right about having to understand the shorthand that's used.
My religious backgroud is that the Bible teaches us how to go to Heaven and not how the Heavens go.
Once upon a time the "how the Heavens go" school believed that the Bible stated that the Sun rotated around the Earth.
How many of even the most Fundamentalist Christians believe that now?
If some insist upon taking every sentence of the Bible literally, snakes can talk.
Such literal interpretations of the Bible are the best way to raise future generations of atheists. How many children nowadays will believe in talking snakes?
As someone posted earlier on this thread:
"If sound science appears to contradict the Bible, we may be sure that it is our interpretation of the Bible that is at fault." ................... Christian Observer, 1832, pg. 437
Oh, I know her. Met her in college
She had these little flaps in her neck and they looked like they might have cartilage in them. It was pretty weird looking.
To this day I can't figure that one out. I only hope she found a plastic surgeon.
Wasn't she fun in the hot tub?
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