Posted on 05/23/2006 4:08:38 AM PDT by PatrickHenry
When ancient whales finally parted company with the last remnants of their legs about 35 million years ago, a relatively sudden genetic event may have crowned an eons-long shrinking process.
An international group of scientists led by Hans Thewissen, Ph.D., a professor of anatomy at Northeastern Ohio Universities College of Medicine, has used developmental data from contemporary spotted dolphins and fossils of ancient whales to try to pinpoint the genetic changes that could have caused whales, dolphins and porpoises to lose their hind limbs.
More than 50 million years ago the ancestors of whales and dolphins were four-footed land animals, not unlike large dogs. They became the sleek swimmers we recognize today during the next 15 million years, losing their hind limbs in a dramatic example of evolutionary change.
"We can see from fossils that whales clearly lived on land - they actually share a common ancestor with hippos, camels and deer," said team member Martin Cohn, Ph.D., a developmental biologist and associate professor with the UF departments of zoology and anatomy and cell biology and a member of the UF Genetics Institute. "Their transition to an aquatic lifestyle occurred long before they eliminated their hind limbs. During the transition, their limbs became smaller, but they kept the same number and arrangement of hind limb bones as their terrestrial ancestors."
In findings to be published this week in the Proceedings of the National Academy of Sciences, scientists say the gradual shrinkage of the whales' hind limbs over 15 million years was the result of slowly accumulated genetic changes that influenced the size of the limbs and that these changes happened sometime late in development, during the fetal period.
However, the actual loss of the hind limb occurred much further along in the evolutionary process, when a drastic change occurred to inactivate a gene essential for limb development. This gene - called Sonic hedgehog - functions during the first quarter of gestation in the embryonic period of the animals' development, before the fetal period.
In all limbed vertebrates, Sonic hedgehog is required for normal limbs to develop beyond the knee and elbow joints. Because ancient whales' hind limbs remained perfectly formed all the way to the toes even as they became smaller suggests that Sonic hedgehog was still functioning to pattern the limb skeleton.
The new research shows that, near the end of 15 million years, with the hind limbs of ancient whales nonfunctional and all but gone, lack of Sonic hedgehog clearly comes into play. While the animals still may have developed embryonic hind limb buds, as happens in today's spotted dolphins, they didn't have the Sonic hedgehog required to grow a complete or even partial limb, although it is active elsewhere in the embryo.
The team also showed why Sonic hedgehog became inactive and all traces of hind limbs vanished at the end of this stage of whale evolution, said Cohn. A gene called Hand2, which normally functions as a switch to turn on Sonic hedgehog, was shown to be inactive in the hind limb buds of dolphins. Without it, limb development grinds to a halt.
"By integrating data from fossils with developmental data from embryonic dolphins, we were able to trace these genetic changes to the point in time when they happened," Thewissen said.
"Studies on swimming in mammals show that a sleek body is necessary for efficient swimming, because projecting organs such as rudimentary hind limbs cause a lot of drag, and slow a swimmer down," said Thewissen, who spends about a month every year in Pakistan and India collecting fossils that document the land-to-water transition of whales.
Researchers say the findings tend to support traditional evolutionary theory, a la Charles Darwin, that says minor changes over vast expanses of time add up to big changes. And while Sonic hedgehog's role in the evolution of hind limbs in ancient whales is becoming apparent, it is still not fully defined.
"It's clear when ancient whales lost all vestiges of the limb it was probably triggered by loss of Sonic hedgehog," said Clifford Tabin, Ph.D., a professor of genetics at Harvard Medical School who was not involved in the research. "But it's hard to say for certain because you're looking at events long after they occurred. As they suggest, there could have been a continual decrease in Sonic as the limbs reduced until the modern version of the animal arrived."
The study itself, combining fossil and developmental data, is notable, Tabin said.
"Whales went through this remarkable transformation to become more like the ancestral fish," Tabin said. "Convergence of evolutionary studies and developmental genetics give us another piece in this growing tapestry of how genetic changes lead to morphological change. It is a remarkable process that was achieved simply and led to profound consequences in how whales were able to survive. Only now in the last five years are we developing this understanding of how the world of evolution is controlled genetically."
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In addition to UF and Northeastern Ohio Universities College of Medicine, scientists from the Natural History Museum of Los Angeles County and the Indian Institute of Technology were involved in the research. Financial support was provided by the National Science Foundation, the National Institutes of Health and the Indian Department of Science and Technology, New Delhi.
"1) What is a "kind"? Same question I asked before, which you did not answer."
<< I don't define it, the Scriptures do. >>
No, they don't. The Bible just says "kinds" without defining what that entails. That's the problem. That's why creationists come up with so many different definitions -- based on the needs of the argument of the moment.
<< Nor would I expect a wolf breeding with a cockerspaniel produce a new "kind", such as a bird. >>
Nor would evolution. A wolf breeding with a cocker spaniel would produce an animal with inherited characteristics of both. Then that creature mating with another animals that IT can breed with produces a new generation with more mixtures of characteristics. Again -- populations evolve -- not individuals.
This whole nonsense about producing radically different species in one generation has nothing to do with the theory of evolution. The fact that you argue in this way says nothing against the theory, but it does say something about yoru lack of understanding of just what it is you are arguing against.
Ever heard of a "ring species"?
<< The creation by God of distinct "kinds" is described in 1 Corinthians 15:38-39 implies that transmutations between kinds is precluded, or at least superfluous.
1 Corinthians 15:38-39 (Holman Christian Standard Bible)
38 But God gives it a body as He wants, and to each of the seeds its own body.
39 Not all flesh is the same flesh; there is one flesh for humans, another for animals, another for birds, and another for fish. >>
Actually -- that does NOT preclude speciation in the least! Nor does it preclude "one flesh" becoming "another flesh." All it is saying is that these large categories are different from each other. In fact, it does not preclude very large developments from one large category of animal to another.
I can see how someone could take from it that "animal flesh" cannot become "man flesh" if one were to take it as a scientific statement concerning limits. But that is not what it is -- and that is not what the discussion in that passage is about. To get THAT meaning from the passage would entail twisting the scripture to make it say something it is not really saying -- and believers are cautioned -- in that same Bible -- against doing such a thing, although that is the standard creationist practice.
"2) What is the scientific mechanism that erects a barrier between kinds, so that evolution can work up to that point, but no further?"
<< Because God created life "each according to its kind" as specified in Genesis. See also, again, 1 Corinthians 15:38-39. The same reason we cannot breed with apes, they are of a different kind. If we were of like kind, then this would be possible. But we're not. >>
So what about domestic wheat being unable to interbreed with emmer grass, which it is clearly descended from? They are of the same "kind" in the sense you are using the term here. There are many, many other examples of such speciation, both in the lab and in nature. That's exactly how evolution works.
And -- quoting a passage of scripture that says how they were created does not give any scientific mechanism by which evolution cannot continue to proceed beyond the arbitrary barrier of a "kind" -- however you choose to define it.
"We may share similar DNA, (what? something like 96%? Can't remember)etc, but this doesn't tell us anything. Clouds are 100% water. Watermellon is approximately 98% water. Are we to conclude they have a similar "make up" and should expect to observe mellons in the sky?"
No offense intended -- but what a stupid argument! Clouds are not living things that reproduce, or have DNA, or undergo genetic mutations, nor are affected by natural selection in terms of survival to reproduction. Melons are. So melons that can interbreed will undergo these processes to the point that some of them eventually cannot interbreed anymore.
That is speciation. And you still have not provided any scientific mechanism that limits the level to which this speciation will take things over a long period of time. Quoting a Bible passage is not exactly a "final answer" to a scientific question.
<< However, the references in the Scriptures clearly use the term "create". Until there is anything compelling that is "discovered" and goes through a proper peer review, I'll still remain within the word of the Gospel otherwise. >>
Plenty has been discovered that is compelling in this regard. Plenty has gone through peer review. Evolution is supported by mountains of evidence. Sticking to a Bible passage that does not even speak to the issue is not "remaining within the word of the Gospel." It is scripture twisting and deliberate closing of one's eyes to the actual evidence.
<< I've tried to honestly and respectly respond to your questions based on my belief system >>
There's the problem. I was trying to have a discussion of science -- not belief systems.
<< 1. Why is it you would discount the word of God and why would you believe that God did not do the things as described? Is God a liar? If God created Man in His image, then why are the Scriptures that difficult to understand/believe--especially in light of the "Y chromosone Adam" discovery? >>
Lots of religious questions. That sounds like a lot of great questions for people to discuss within the framework of shared presuppositions. We do not share the same presuppositions about scripture. You have no idea what I "believe" about "God" -- so asking a question like, "Did God lie?" has no relevance.
<< 2. Why is it important to put your faith in what Man tells you rather than an all encompassing God? >>
I am not "putting my faith" in anything. I am studying the evidence -- and I accept the conclusions of evolution based on a study of the evidence that has been found. That is not "faith." I am not "embracing" it either. I am not emotionally attached to it.
I don't care where the evidence leads. If it were to lead elsewhere, I would follow it there -- and so would all honest scientists. As history has shown, many scientists -- who are just as flawed as everyone else -- have shown resistance to new evidence that calls into question what they have accepted as the best scientific answer.
But with the way science works -- with the competition, the peer review, the rush to disprove each other, the desire to be the one to find that next great discovery -- eventually, we all are dragged along by the evidence. The biblical idea of a universal flood was abandoned before Darwin came along, and it was abandoned by "creationists" who found that the evidence simply wasn't there to support it.
The evidence for evolution does not have feelings, or intentions, or goals. It's just what it is. Our feelings about it -- our feelings about how it may fit or contradict our cherished religious beliefs -- our desire to be right -- none of these things has any relevance to the truth value of the evidence itself.
Ya wanna discuss religion -- ya got the wrong guy, and the wrong thread.
"I don't care where the evidence leads. If it were to lead elsewhere, I would follow it there..."
I don't think we have a disagreement there. You haven't answered the questions I've proposed. I've admitted that my beliefs are based on faith. However, you've not explained why you have faith in evolution and not the Scriptures. And you have to have a certain degree of faith to believe in evolution. I gave you an example of thoroughbred horses vis a vis your grass/wheat conjecture. Mine is the same conjecture. Did you not see it?
I agree that the "flesh" Scripture does not necessarily preclude the possibility of speciation--from a microevolutionary point of view. However, I don't get your point about this is "twisted".
LOL! Yeah, the mellon thing was a stretch, but one to demonstrate that commonalities do not equate realities--best I could come up with at 1AM.
Well, if God lied, then what's the point of any of it? And what else is "incorrect"? Either God has transcribed His word properly and is right and evolution is incorrect or the Bible is wrong and evolution is right. Based on the references of "creation" used in the Bible, I lean to the later obviously.
"There's the problem. I was trying to have a discussion of science -- not belief systems."
I see no incompatibility with science and the Scriptures. In fact, I think it goes hand in hand--although you're well aware of my thoughts on evolution. If God is the Creator, He certainly created the laws of science. And tho the Scriptures aren't science based, per se, there's many scientific truths disclosed in the Scriptures--much undiscovered by Man until recently.
Heck, even Richard Dawkins is compelled to comment on the "evils" of religion and Christianity. So apparently he believes it's germaine to the topic, eventhough obsecure.
When I asked if "God is a liar", it's a rhetorical question. Not specific to you.
"This whole nonsense about producing radically different species in one generation has nothing to do with the theory of evolution. The fact that you argue in this way says nothing against the theory, but it does say something about yoru lack of understanding of just what it is you are arguing against. "
Well, you boil it down and what do you have? Evolutionist do their darnest to avoid the question--where did we come from after the primates? I understand it quite well. Darwin, in his Orgin of Species, speculated that..."all the organic beings, which have ever lived on the earth, may be descended from some one primordial form." I'm paraphrasing, but that was essentially his doctrine. So the basic premise, or it's basic original tenent included this "idea".
I never concluded that "producing radically different species in one generation" was part of my argument. You came up with that one on your own. Besides, I don't believe it would happen in one generation or 10,000 generations.
Sure, what's your point about ring species? It's Darwin's birds and different beaks--based on geographic restrictions. They're still birds--and probably related to the concept of "microevolution" or evironment adaptation. If I recall, they used to tie this into "natural selection". The conjecture is that these critters have not inter-breeded--based on geography. But I don't believe its been observed whether they inter-bred or not. If they had, it wouldn't take too many times. And I think any biologist would agree that speciation would be difficult to prove, in this case, as it would exceed his lifetime to observe the process--given the essence of time required for the theory.
"You haven't answered the questions I've proposed."
You are proposing religious and philosophical questions that have nothing to do with the topic if the thread. If I wanted to argue different religious perspectives, I would have joined a religous thread. You are the one making the mistake of turning a science thread into a religious one -- the classic creationist mistake.
"I've admitted that my beliefs are based on faith. However, you've not explained why you have faith in evolution and not the Scriptures."
I explained that I do not have "faith" in evolution. I accept the evidence so far. That's it. You won't even consider the evidence, because you are convinced it will conflict with your religous "faith." Fine by me.
"And you have to have a certain degree of faith to believe in evolution. I gave you an example of thoroughbred horses vis a vis your grass/wheat conjecture. Mine is the same conjecture. Did you not see it?"
Emmer grass to wheat evolution is not conjecture. It's evidence. And horse evolution is based on very strong evidence, too.
"I agree that the "flesh" Scripture does not necessarily preclude the possibility of speciation--from a microevolutionary point of view. However, I don't get your point about this is 'twisted'."
You are a Christian, and you want to use the Bible in your arguments, and you don't know what "scripture twisting" is? Tell you what -- this is way off topic, but if you are interested, I would be happy to send you a list of good references, privately, on hermeneutics. I'll even include only conservative sources. Just let me know.
{Snip irrelevant religious philosophizing]
"I see no incompatibility with science and the Scriptures."
Oh, yes, you do! You refuse any evidence that threatens to contradict what you think the Bible says. And you argue about scientific issues that you clearly do not understand, and that you clearly have not studied -- except for some creationist propaganda designed to protect a literalistic interpretation of Genesis.
"If God is the Creator, He certainly created the laws of science. And tho the Scriptures aren't science based, per se, there's many scientific truths disclosed in the Scriptures--much undiscovered by Man until recently."
That's nonsense. If you believe the literal reading of the first two chapters of Genesis are scientifically accurate, you are not looking at science at all -- and you probably never will. It's not my goal in life to try to argue people out of their religious beliefs. I just wish they would stop trying to cram those beliefs in where they do not belong -- such as science class.
"Heck, even Richard Dawkins is compelled to comment on the 'evils' of religion and Christianity. So apparently he believes it's germaine to the topic, eventhough obsecure."
He's an aggressive atheist. I am not. Nor are most people who accept evolution -- including many Christians. You are in great error in your attempt to couch this issue in the terms of a religous conflict -- but that IS the only pony the creationists can ride.
"When I asked if "God is a liar", it's a rhetorical question. Not specific to you."
That question has so many assumptions in its foundation that we would be discussing them for weeks before even getting to the question itself. That is why I am leaving it alone, as it has nothing to do with the scientific issue of this thread. "Have you stopped beating your wife?" is simple in comparison!
"Well, you boil it down and what do you have? Evolutionist do their darnest to avoid the question--where did we come from after the primates?"
Evolutionists are not avoiding anything. The family tree of living things is pretty well filled out, even though we will continue to learn more and more. No one has avoided saying where "primates" came from.
"I understand it quite well."
I don't believe you. I am not saying you are lying, but I don't believe you really understand it at all. Your arguments are evidence of this.
"Darwin, in his Orgin of Species, speculated that...'all the organic beings, which have ever lived on the earth, may be descended from some one primordial form.'"
Ah -- so now we are back to abiogenesis. It really gets tiring. The two fields are not related, and the fact that some evolutionists address abiogenesis, even in passing, does not make a lack of answers for abiogenesis an issue at all. Life IS here -- and things have progressed quite a bit since Darwin was on the scene.
"I'm paraphrasing, but that was essentially his doctrine."
No, it wasn't. You said he said he "speculated" and said "may." That ain't doctrine, unless you are ready to concede that when you say, "Maybe Jesus was freckle-faced" you are preaching doctrine.
"So the basic premise, or it's basic original tenent included this 'idea'."
No, it doesn't. It doesn't matter how life started. Evolution happened, and is happening, whatever got life started, and HOWEVER it got started. You are beating a dead horse.
"Besides, I don't believe it would happen in one generation or 10,000 generations."
Fortunately for science, your personal incredulity does not constitute evidence.
Look -- rather than continuing to argue ridiculous points like this -- let me just suggest that you at least try to study the actual evidence more objectively, instead of looking for loopholes in order to attack it from a narrow, specific, religious perspective. Talk Origins is the most comprehensive site on the net that explains all these issues in some detail, and it gives plenty of references for further study.
You seem to think you have found the "magic bullet" unanswerable question that destroys evolution at its core -- but you haven't. You haven't brought up one thing that hasn't been brought up -- and answered -- a hundred times before.
I was a YEC for twenty years, and I was right where you are. I thought I was so clever and could "trap" the stupid evos so easily with my killer questions that destroyed the theory. But I was just making a fool of myself.
You will never understand this until -- unless -- you decide to examine the evidence more objectively, rather than as an apologist for your religious ideas. You may never do so; plenty never do. But I dare you to try.
But if you don't -- it's no skin off my teeth -- unless you try to force your own narrow religious view into science class. That I will resist.
"But if you don't -- it's no skin off my teeth -- unless you try to force your own narrow religious view into science class. That I will resist."
Look, what I'm saying is the so called evidence is open to interpretation. You're right about the point about Darwin--given he speculated we came from one source--that the "evidence" changes. And I suspect the "evidence" will continue to change--evolve, so to speak. Personally, I'm not ready to put my money on that horse. And honestly, you've not answered much other than pose questions.
I'm not trying to convince you of one thing. You've made you're choice. You've put your faith into Man. If you're right, then when we die, we're just dead. If you're wrong, then we're subject to the wrath and judgment of God. If God is God, then He is supreme to "science" as He created it. I have no problems with anyone who wants to believe in evolution. But I take exception to the idea of "mountains of evidence". It's mountains of conclusions based on a theorized or supposed outcome, not evidence of proven or observed fact. I hear people talk about "mountains", but I never see much of anything but a mole hill. Whether you think I've "looked" at the "evidence" or not, is not material to me. I have admitted my beliefs are faith based, you won't--and believe me, I'm not looking for you to do so. Not important to me.
I don't know anything about this "YEC" you reference, but earlier I admitted I originally considered majoring in paleontology. Primarily because of love of history, anthropology, etc. I choose to bag this as a career because the conclusions that were made were so obsecure and full of conjecture, I couldn't see how anyone could come to these conclusions. When someone found a bone fragment, a skull cap, piece of tooth--all of a sudden we could get a idea of their culture, how they lived, what they thought and even how they looked. Nonsense. If God wants to make evolution a process of life, that's ok with me. He is supreme. He can do as He wants. But it's not clear to me why God would tell us that there was no death until it was introduced by Adam (man) and yet, use "evolution" that is in contradiction to what He said. Either God has lied or told us the truth. That doesn't take weeks of discussion.
I'm not interested in religion, only the word of God. Religion and God, are two different items, in my opinion. So I'm not an apologist on "religious" ideas. I could care less about "religion". What I care about is precisely what God says.
Yes, I've actually read the Orgin of Species. And despite all the howlings that "I didn't have a clue" about the "theory" of evolution because I made the comment about "goo to man", these were the charges. And I think you've demonstrated this was and is a basic platform--given it was a speculation from Darwin himself. Whether or not it still is, or has been edited out of other editions--I couldn't tell you, the trained evolutionists still avoid the question 'where'd we come from before the primates'--thus it's not part of the theory. So when you claim "No one has avoided saying where "primates" came from." They most certainly have! Scroll up and review the charges of "you don't know anything about the theory of evolution".
I know what "twisting" is and I haven't a clue what you're saying about that in relation to 1 Corinthians 15:38-39. It's pretty clear to me.
When are people expecting the "population" of eskimos to evolve fur? They've supposedly been living around the artic circle for 20,000 to 100,000 years--you pick the time, everyone else does. Maybe they need millions of years. Heck, throw a billion in there. Since evolution has been "observed", then we can base a reasonable projection when this will occur.
I think God and science are not contradictions. We've obviously cross paths on the spectrum of belief. I have gone from one side of the spectrum toward the faith in God. You've gone from that point toward evolution. It's not really germaine what each of us believe. We'll find out soon enough when we "croak". Either the Scriptures are right or they're wrong. Either God told us the truth that all things were created by Jesus or it's wrong. Either we came from a heap of goo or we were created in one day as God says. Either Jesus Christ is the only way to salvation or this is wrong. That's the only elements material to this entire discussion. As I mentioned earlier, if I'm wrong, then I'm just dead. But if the Scriptures are right, then we have the promise of salvation and ever lasting life. It's not a bet I'm willing to take.
Seriously, I'm not trying to convince you of anything. But I have enjoyed talking with you. You'll believe what you want, and I will as well. I don't think any less of you, regardless--or any other evolutionist, for that matter. Time and life is too short. My only point to you and other evolutionists asks the question "Did God lie"? I believe the answer is "no". You see this as a contradiction to the theory or the debate, I see it as no contradiction. If God is the supreme being, He created everything. And why would He need to use evolution? Surely, for a God that created all the wonders of the universe, He can certainly get the creation of man right on the first time around.
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