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.'
It sure is!
Sea life (Fish) came first, then land animals, then reptiles, then the mammals, then the lower primates, then Man.
There's a lot of begat's there. So the theory goes.
It would already be in place. The "low number of offspring with protective mother" develops very early in the evolutionary process.
Bird mothers protect their young fiercely and even protect their eggs a lot more firecely that some Liberal human mothers protect their unborn.
Sorry again, 1000 generations is waaaaaaaaaay too short a time period for that to be seen.
So exactly how many generations do I have to go back before I have a monkey in my family tree? Ten thousand? A million? There is no evidence of human beings existing that far back. So where is the missing link? Where are the fossil remains of pseudo human life? Who procreated with the gorilla to produce the human? What environmental factors resulted in fish turning into people? When did they start crawling out of the muck?
Using your much-vaunted "scientific method," I'm sure you have the answer supported by hard science. Or at least you "probably" have a "viable theory" based upon "conclusions" that are "reasonable to suggest."
Your scientific method is what comes out the south end of a north-bound horse.
God created me. If you're the offspring of lesser primates, then that's your problem.
This is my point exactly. Scientific evidence is considered by most as absolute proof, when in fact the equations keep changing. Darwinism is considered science, so therefore people believe it must be an indisputable truth. I was first introduced to Darwinism in a middle school science class. No alternative "theory" was allowed to be discussed.
Natural selection cannot explain the existance of mankind. Generational variations in the genetics of lifeforms, cross-breeding, and environmental adaptation cannot explain the leap from single-celled organisms to human beings.
Sure you do, lots of them.
Merry Christmas!
Wrong. It's the scientists who come up with ridiculous theories that lack credibility. When a self-proclaimed "scientist" proposes that our glands used to be gills just because they have "similarities," it diminishes the veracity of their methodology. The scientific method used by evolutionists is fundamentally flawed. They started with a conclusion that they view as indisputable, and then they try to mold the evidence to fit the conclusion.
It's no different than crime scene investigators showing up at a murder scene, and then proclaiming that they know for certain "who done it." Any investigation proceeding that conclusion will be an attempt to link the evidence to their suspect, instead of using the evidence to identify the culprit. This is the primary fallacy of the scientific method when applied to evolution theory. It's founded entirely on a conclusion that really has no evidence to support it.
YOUR interpretation of the Bible leads you to believe that evolution is bogus and you hold that on faith alone, so debating anything about the subject using science is pointless.
Evolution is just as much faith-based as a belief in God. There are certain things that cannot be explained by science. Our existance is at the top of that list. Using scientific method to explain our existance is like using astrology to explain intestinal cancer.
Carrying your metaphor, isn't Java really the language of creationists? After all, its objects are destroyed, not by well known deterministic mechanisms, but by mysterious forces over which you have no control. Garbage collection is like The Flood: all at once, somebody outside the program notices bad things piling up and decides to get rid of them in one fell swoop, and depending on the vagaries of time slicing, some may still survive.
Can't seem to work a serpent in there, though... or a pillar of salt... or a burning bush... though many is the late night coding I've felt I was wandering in the wasteland for about 40 years.
Human Ancestors.
The Evidence for Human Evolution.
Comparison of all Hominid skulls.
I've posted these next links before, but they're needed again:
The Theory of Evolution. (Excellent introductory encyclopedia article.)
It might help to learn what science is: The scientific method.
You: Really intelligent people know that evolution is a fact and the theory of evolution explains that fact.
"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
"Christians should look on evolution simply as the method by which God works." Rev. James McCosh, theologian and President of Princeton, 1890
Me: I don't care how many godless mortals state evolution is a fact - which it is NOT. It is a HYPOTHESIS and has NO evidence to back it up.
I don't know about you ... but humans are made in the image of God and He is NO ape! SO all your godless theoologians don't impress me either!
All the scientific deceptions and prejudiced evaluations made to support the theory of evolution show that the theory is a kind of ideology, and not at all a scientific account. Like all ideologies, this one too has its fanatical supporters, who are desperate to prove evolution, at no matter what cost. Or else they are so dogmatically bound to the theory that every new discovery is perceived as a great proof of the theory, even if it has nothing to do with evolution. This is really a very distressing picture for science, because it shows that science is being misdirected in the name of a dogma.
In considering the theory of human evolution it is interesting to note that some very well known scientists have actually suggested that the line of human evolution is far from clear. For example, in 1990, Richard Leakey himself said that, "If pressed about man's ancestry, I would have to unequivocally say that all we have is a huge question mark. To date, there has been nothing found to truthfully purport as a transitional specie to man, including Lucy, since 1470 was as old and probably older. If further pressed, I would have to state that there is more evidence to suggest an abrupt arrival of man rather than a gradual process of evolving." 10
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