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.'
Uh, actually, there is.
Uh, actually, no there's not. A human generation is 20-22 years. There is no paleoarcheological fossil evidence dating back 20-22 million years.
Judge not lest ye be judged.
Uh, actually, there is.
No, there really isn't.
The Miocene Epoch: 5.3 - 23.8 Million years ago (20 million years is roughly 1 million human generations)
The Miocene was a time of warmer global climates than those in the preceeding Oligocene, or the following Pliocene. It is particularly notable in that two major ecosystems first appeared at this time: kelp forests and grasslands. The expansion of grasslands is correlated to a drying of continental interiors as the global climate first warmed and then cooled. The largest animal life was characterized by Chalicotherium, a Miocene mammal from Kazakhstan. Chalicotherium was an unusual "odd-toed" hoofed mammal, or perissodactyl.
Please post your link to a 20-million-year-old hominid skeleton.
That's the point. If you could trace your ancestors back far enough, you'd find that they didn't look very human. Nothing to be embarrassed about. It happens in the best of families.
The figures were 10k and a million. Not 20-22 million.
The apostles and men of God throughout the Bible addressed what they called FALSE TEACHERS. Deceivers who claim to represent God but do not.
I hardly think "Judge not lest ye be judged" means Jesus wants us to completely naive about such things.
Unless of course He wants to judge His own disciples and men of God in the Bible.
I don't think so.
But nice try anyway! :)
My apologies to freedomfiter2.
Thanks Gondring.
And what tail isn't?
"Most" who? Not ANY scientists.
So God stands erect? God lacks the thick fur of apes? God has a nose? A runny nose? A mouth? An intestine? Gas pains? Does God eructate? Do God's toenails on each of his 10 toes on his two legs need occasional clipping? Is God muscular like Arnold Schwarzenegger or skinny like PeeWee? Is God dark skinned or light? Does he have an umbilicus? Do his lungs contain accessory fissures? Is his appendix retrocecal? Can we rest assured God has two testicles and a penis?
Why do persist with such nonsense? Your literal interpretation of "image" is so obviously ridiculous that surely even your cult hasn't blinded you to it.
So is my neighbor's beagle.
Jorge, why are you being such a dink? You know I didn't accuse Christ of anything. I accused YOU of things. And I was right. Do you or do you not think that Christ believes in poofism? You attribute the idiocy of the creationist positions to Christ. In other words, you take him for a dolt.
So you attribute the lower bladder infection rate of males to the fact that the prostate encircles the urethra, not to the urethral length--and you also don't think that a non-encircling arrangement would provide function without the negatives?
And of course the testes descend and like it outside the body, but there's surely a better design than one susceptable to inguinal hernias, were you to design from scratch and not evolve a design.
But you're right... Maybe when I go to heaven, God will explain all the pseudogenes.
'Course, I don't believe in Pascal's Wager being effective, so I probably won't make it there...according to some.
The false teachers are the ones you have been listening to about science.
'Course, I don't believe in Pascal's Wager being effective, so I probably won't make it there...according to some."
Right, you have to ACTUALLY believe in God to have salvation. It is not like pretending to have moral values like the Rats do to try to get elected.
I assume the beagle flunked obedience training. What is your neighbor going to do now?
"Is his appendix retrocecal?"
Good question! Good word!
Sigh, one would hope Christians would understand the Bible is more about spiritual things than anatomy.
Dear Mary,
You did not evolve from an ape. You evolved from a common ancestor of apes and man. In fact, man is a hairless ape.
The apes are far smarter than the common ancestor was, probably.
I hope this information doesn't mess up Christmas for all the apes you are having over for dinner.
God bless,
shubi
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