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.'
Much of your DNA is in common with the banana and cucumber.
How would that have imparted a survival advantage for the deer?
"And let us make man in oue image"
Image being the key word here. I still don't think God looks like a fish.
Oops "OUR" image.
Then how does it explain the religious evolutionists?
This could be true...my wife says mine has a lot of "apeel"!
Ahhhh. So that's where I get it.
"Then how does it explain the religious evolutionists?"
I think it is this that irks me the most about the cult of creationism. They think they are Christians, but don't act like it and exclude those of us from their "god" who they think is our God.
Thank you! I knew there had to be a better medical description for this condition.
It works for the elephant. The deer has other ways to escape.
You are clearly less devout than they, and less beloved by God. When you die, God will have some sort of punishment for you for not being a poofist.
In the end, these are people less concerned about being right than about being accepted by and defending their particular cult.
Thank you!
The question was regarding why the deer's neck fits the lion's mouth. It seems unlikely that the fit is to the deer's advantage.
All creationists seem to know that punctuated equilibrium is also known as the "hopeful monster" theory. Everything creationists know about evolution is wrong, wrong, wrong. Yet somehow we're supposed to believe they know what they're talking about when they say evolution is wrong.
Wrong!
LOL, or maybe the peanut family. Hey, just kidding!
I did find evolution "convincing" BEFORE I meet Christ.
I don't know a single genuine believer in Christ who accepts evolution.
The author of evolution sure didn't.
What did Charles Darwin himself believe about the role of God in evolution? Darwin expert Neal Gillespie, in his book CHARLES DARWIN AND THE PROBLEM OF CREATION (1974, p. 141), said that "Darwin clearly rejected Christianity and virtually all conventional arguments in defense of the existence of God and human immortality."
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."
Clearly! LOL
Merry Christmas!
Sometimes you do see an "arms race" situation in nature. Classic example: cheetahs are very good at running down gazelles, but gazelles are very good at running away from cheetahs. Both are evolved for speed.
Some kind of match/mismatch might have erupted between the cougar's mouth and the deer's neck, but it's a sideshow. The main strategy for the deer is of course to keep his neck out of the cougar's mouth in the first place. There are probably other pressures keeping the deer's neck about what it is.
With all due respect, you sir are liar. I never accused Christ of any such thing.
You the one characterizing Christ of "believing or professing absurdities" and in your previous post accused Him of being a "deceiver".
And you post this inflamatory nonsense simply because my stated beliefs in Christ don't agree with your positions on evolution.
I have learned that this is the sort of angry, bitter and intellectually dishonest rhetoric we can expect from evolutionists when they are confronted with Christ and those who believe Him and God's Holy Word.
Nothing you say is a surprise to me. I was where you are years ago before I met Christ.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.