Posted on 05/01/2006 8:29:14 AM PDT by SirLinksalot
Dinosaur Shocker
By Helen Fields
Neatly dressed in blue Capri pants and a sleeveless top, long hair flowing over her bare shoulders, Mary Schweitzer sits at a microscope in a dim lab, her face lit only by a glowing computer screen showing a network of thin, branching vessels. Thats right, blood vessels. From a dinosaur. Ho-ho-ho, I am excite-e-e-e-d, she chuckles. I am, like, really excited.
After 68 million years in the ground, a Tyrannosaurus rex found in Montana was dug up, its leg bone was broken in pieces, and fragments were dissolved in acid in Schweitzers laboratory at North Carolina State University in Raleigh. Cool beans, she says, looking at the image on the screen.
It was big news indeed last year when Schweitzer announced she had discovered blood vessels and structures that looked like whole cells inside that T. rex bonethe first observation of its kind. The finding amazed colleagues, who had never imagined that even a trace of still-soft dinosaur tissue could survive. After all, as any textbook will tell you, when an animal dies, soft tissues such as blood vessels, muscle and skin decay and disappear over time, while hard tissues like bone may gradually acquire minerals from the environment and become fossils. Schweitzer, one of the first scientists to use the tools of modern cell biology to study dinosaurs, has upended the conventional wisdom by showing that some rock-hard fossils tens of millions of years old may have remnants of soft tissues hidden away in their interiors. The reason it hasnt been discovered before is no right-thinking paleontologist would do what Mary did with her specimens. We dont go to all this effort to dig this stuff out of the ground to then destroy it in acid, says dinosaur paleontologist Thomas Holtz Jr., of the University of Maryland. Its great science. The observations could shed new light on how dinosaurs evolved and how their muscles and blood vessels worked. And the new findings might help settle a long-running debate about whether dinosaurs were warmblooded, coldbloodedor both.
Meanwhile, Schweitzers research has been hijacked by young earth creationists, who insist that dinosaur soft tissue couldnt possibly survive millions of years. They claim her discoveries support their belief, based on their interpretation of Genesis, that the earth is only a few thousand years old. Of course, its not unusual for a paleontologist to differ with creationists. But when creationists misrepresent Schweitzers data, she takes it personally: she describes herself as a complete and total Christian. On a shelf in her office is a plaque bearing an Old Testament verse: For I know the plans I have for you, declares the Lord, plans to prosper you and not to harm you, plans to give you hope and a future.
It may be that Schweitzers unorthodox approach to paleontology can be traced to her roundabout career path. Growing up in Helena, Montana, she went through a phase when, like many kids, she was fascinated by dinosaurs. In fact, at age 5 she announced she was going to be a paleontologist. But first she got a college degree in communicative disorders, married, had three children and briefly taught remedial biology to high schoolers. In 1989, a dozen years after she graduated from college, she sat in on a class at Montana State University taught by paleontologist Jack Horner, of the Museum of the Rockies, now an affiliate of the Smithsonian Institution. The lectures reignited her passion for dinosaurs. Soon after, she talked her way into a volunteer position in Horners lab and began to pursue a doctorate in paleontology.
She initially thought she would study how the microscopic structure of dinosaur bones differs depending on how much the animal weighs. But then came the incident with the red spots.
AdvertisementIn 1991, Schweitzer was trying to study thin slices of bones from a 65-million-year-old T. rex. She was having a hard time getting the slices to stick to a glass slide, so she sought help from a molecular biologist at the university. The biologist, Gayle Callis, happened to take the slides to a veterinary conference, where she set up the ancient samples for others to look at. One of the vets went up to Callis and said, Do you know you have red blood cells in that bone? Sure enough, under a microscope, it appeared that the bone was filled with red disks. Later, Schweitzer recalls, I looked at this and I looked at this and I thought, this cant be. Red blood cells dont preserve.
Schweitzer showed the slide to Horner. When she first found the red-blood-cell-looking structures, I said, Yep, thats what they look like, her mentor recalls. He thought it was possible they were red blood cells, but he gave her some advice: Now see if you can find some evidence to show that thats not what they are.
What she found instead was evidence of heme in the bonesadditional support for the idea that they were red blood cells. Heme is a part of hemoglobin, the protein that carries oxygen in the blood and gives red blood cells their color. It got me real curious as to exceptional preservation, she says. If particles of that one dinosaur were able to hang around for 65 million years, maybe the textbooks were wrong about fossilization.
Schweitzer tends to be self-deprecating, claiming to be hopeless at computers, lab work and talking to strangers. But colleagues admire her, saying shes determined and hard-working and has mastered a number of complex laboratory techniques that are beyond the skills of most paleontologists. And asking unusual questions took a lot of nerve. If you point her in a direction and say, dont go that way, shes the kind of person wholl say, Why?and she goes and tests it herself, says Gregory Erickson, a paleobiologist at Florida State University. Schweitzer takes risks, says Karen Chin, a University of Colorado paleontologist. It could be a big payoff or it could just be kind of a ho-hum research project.
In 2000, Bob Harmon, a field crew chief from the Museum of the Rockies, was eating his lunch in a remote Montana canyon when he looked up and saw a bone sticking out of a rock wall. That bone turned out to be part of what may be the best preserved T. rex in the world. Over the next three summers, workers chipped away at the dinosaur, gradually removing it from the cliff face. They called it B. rex in Harmons honor and nicknamed it Bob. In 2001, they encased a section of the dinosaur and the surrounding dirt in plaster to protect it. The package weighed more than 2,000 pounds, which turned out to be just above their helicopters capacity, so they split it in half. One of B. rexs leg bones was broken into two big pieces and several fragmentsjust what Schweitzer needed for her micro-scale explorations.
It turned out Bob had been misnamed. Its a girl and shes pregnant, Schweitzer recalls telling her lab technician when she looked at the fragments. On the hollow inside surface of the femur, Schweitzer had found scraps of bone that gave a surprising amount of information about the dinosaur that made them. Bones may seem as steady as stone, but theyre actually constantly in flux. Pregnant women use calcium from their bones to build the skeleton of a developing fetus. Before female birds start to lay eggs, they form a calcium-rich structure called medullary bone on the inside of their leg and other bones; they draw on it during the breeding season to make eggshells. Schweitzer had studied birds, so she knew about medullary bone, and thats what she figured she was seeing in that T. rex specimen.
Most paleontologists now agree that birds are the dinosaurs closest living relatives. In fact, they say that birds are dinosaurscolorful, incredibly diverse, cute little feathered dinosaurs. The theropod of the Jurassic forests lives on in the goldfinch visiting the backyard feeder, the toucans of the tropics and the ostriches loping across the African savanna.
To understand her dinosaur bone, Schweitzer turned to two of the most primitive living birds: ostriches and emus. In the summer of 2004, she asked several ostrich breeders for female bones. A farmer called, months later. Yall still need that lady ostrich? The dead bird had been in the farmers backhoe bucket for several days in the North Carolina heat. Schweitzer and two colleagues collected a leg from the fragrant carcass and drove it back to Raleigh.
AdvertisementAs far as anyone can tell, Schweitzer was right: Bob the dinosaur really did have a store of medullary bone when she died. A paper published in Science last June presents microscope pictures of medullary bone from ostrich and emu side by side with dinosaur bone, showing near-identical features.
In the course of testing a B. rex bone fragment further, Schweitzer asked her lab technician, Jennifer Wittmeyer, to put it in weak acid, which slowly dissolves bone, including fossilized bonebut not soft tissues. One Friday night in January 2004, Wittmeyer was in the lab as usual. She took out a fossil chip that had been in the acid for three days and put it under the microscope to take a picture. [The chip] was curved so much, I couldnt get it in focus, Wittmeyer recalls. She used forceps to flatten it. My forceps kind of sunk into it, made a little indentation and it curled back up. I was like, stop it! Finally, through her irritation, she realized what she had: a fragment of dinosaur soft tissue left behind when the mineral bone around it had dissolved. Suddenly Schweitzer and Wittmeyer were dealing with something no one else had ever seen. For a couple of weeks, Wittmeyer said, it was like Christmas every day.
In the lab, Wittmeyer now takes out a dish with six compartments, each holding a little brown dab of tissue in clear liquid, and puts it under the microscope lens. Inside each specimen is a fine network of almost-clear branching vesselsthe tissue of a female Tyrannosaurus rex that strode through the forests 68 million years ago, preparing to lay eggs. Close up, the blood vessels from that T. rex and her ostrich cousins look remarkably alike. Inside the dinosaur vessels are things Schweitzer diplomatically calls round microstructures in the journal article, out of an abundance of scientific caution, but they are red and round, and she and other scientists suspect that they are red blood cells.
Of course, what everyone wants to know is whether DNA might be lurking in that tissue. Wittmeyer, from much experience with the press since the discovery, calls this the awful questionwhether Schweitzers work is paving the road to a real-life version of science fictions Jurassic Park, where dinosaurs were regenerated from DNA preserved in amber. But DNA, which carries the genetic script for an animal, is a very fragile molecule. Its also ridiculously hard to study because it is so easily contaminated with modern biological material, such as microbes or skin cells, while buried or after being dug up. Instead, Schweitzer has been testing her dinosaur tissue samples for proteins, which are a bit hardier and more readily distinguished from contaminants. Specifically, shes been looking for collagen, elastin and hemoglobin. Collagen makes up much of the bone scaffolding, elastin is wrapped around blood vessels and hemoglobin carries oxygen inside red blood cells.
Because the chemical makeup of proteins changes through evolution, scientists can study protein sequences to learn more about how dinosaurs evolved. And because proteins do all the work in the body, studying them could someday help scientists understand dinosaur physiologyhow their muscles and blood vessels worked, for example.
Proteins are much too tiny to pick out with a microscope. To look for them, Schweitzer uses antibodies, immune system molecules that recognize and bind to specific sections of proteins. Schweitzer and Wittmeyer have been using antibodies to chicken collagen, cow elastin and ostrich hemoglobin to search for similar molecules in the dinosaur tissue. At an October 2005 paleontology conference, Schweitzer presented preliminary evidence that she has detected real dinosaur proteins in her specimens.
Further discoveries in the past year have shown that the discovery of soft tissue in B. rex wasnt just a fluke. Schweitzer and Wittmeyer have now found probable blood vessels, bone-building cells and connective tissue in another T. rex, in a theropod from Argentina and in a 300,000-year-old woolly mammoth fossil. Schweitzers work is showing us we really dont understand decay, Holtz says. Theres a lot of really basic stuff in nature that people just make assumptions about.
young-earth creationists also see Schweitzers work as revolutionary, but in an entirely different way. They first seized upon Schweitzers work after she wrote an article for the popular science magazine Earth in 1997 about possible red blood cells in her dinosaur specimens. Creation magazine claimed that Schweitzers research was powerful testimony against the whole idea of dinosaurs living millions of years ago. It speaks volumes for the Bibles account of a recent creation.
This drives Schweitzer crazy. Geologists have established that the Hell Creek Formation, where B. rex was found, is 68 million years old, and so are the bones buried in it. Shes horrified that some Christians accuse her of hiding the true meaning of her data. They treat you really bad, she says. They twist your words and they manipulate your data. For her, science and religion represent two different ways of looking at the world; invoking the hand of God to explain natural phenomena breaks the rules of science. After all, she says, what God asks is faith, not evidence. If you have all this evidence and proof positive that God exists, you dont need faith. I think he kind of designed it so that wed never be able to prove his existence. And I think thats really cool.
By definition, there is a lot that scientists dont know, because the whole point of science is to explore the unknown. By being clear that scientists havent explained everything, Schweitzer leaves room for other explanations. I think that were always wise to leave certain doors open, she says.
But schweitzers interest in the long-term preservation of molecules and cells does have an otherworldly dimension: shes collaborating with NASA scientists on the search for evidence of possible past life on Mars, Saturns moon Titan, and other heavenly bodies. (Scientists announced this spring, for instance, that Saturns tiny moon Enceladus appears to have liquid water, a probable precondition for life.)
Astrobiology is one of the wackier branches of biology, dealing in life that might or might not exist and might or might not take any recognizable form. For almost everybody who works on NASA stuff, they are just in hog heaven, working on astrobiology questions, Schweitzer says. Her NASA research involves using antibodies to probe for signs of life in unexpected places. For me, its the means to an end. I really want to know about my dinosaurs.
AdvertisementTo that purpose, Schweitzer, with Wittmeyer, spends hours in front of microscopes in dark rooms. To a fourth-generation Montanan, even the relatively laid-back Raleigh area is a big city. She reminisces wistfully about scouting for field sites on horseback in Montana. Paleontology by microscope is not that fun, she says. Id much rather be out tromping around.
My eyeballs are just absolutely fried, Schweitzer says after hours of gazing through the microscopes eyepieces at glowing vessels and blobs. You could call it the price she pays for not being typical.
What do you mean specifically? Are you suggesting that the several isotopes of Sr behave differently chemically? If not, then how will you arrange to vary the ratio of their concentrations in the minute parts of a lava flow that form a single zircon?
What can happen, according to what I've read, is that a zircon can be pulled into a later flow and act as the nucleus for additional crystal formation. Then the isochron won't give any age, or rather it would give two if we had enough data points.
Um, no.
Decay rates are 'normed' by the study of radioactive decay rates in the laboratory (which can be done very accurately). Daughter decay products that are known to not be present in newly solidified rock are what is searched for. Data that doesn't converge is thrown out because it obviously does represent a system that has not remained closed or was otherwise contaminated. Yes, spurious, anomalous results (like a couple measurements of 34 billion-year ages that don't get any cross-validation), that don't have any bearing on the measured quantity in a different sample, are often thrown out, but not because "they don't like them", because there are other reasons to believe the measurement is suspect. That's not fabrication of data, it's the proper way of dealing with statistics.
Yep.
I know I'm not going to convince those engaging in the debate.
It's good to know that others people are getting it, though.
That's my goal.
Thanks.
The ToE is tightly defined regarding the development of mammals by taxonomy, DNA relationships, and the extensive reptilian to mammalian transitional fossil record. It is not an overstatement at all to say that finding a true mammal in the Devonian time period would obliterate the ToE.
Finding a footprint that just reminds us of a bear's, on the other hand, merely indicates the possibility of a previously undiscovered evolutionary branch. That would certainly qualify as a find worthy of an extensive revision of the ToE regarding the Permian Age, though, and that is what MacDonald was saying.
The next time I get a straight answer out of you will be the first.
There can be no physical causation in the absence of space/time - of the geometry. Were it not for time, events could not occur. Were it not for space, things could not be.
And we know there was a beginning of space/time in this universe. All cosmologies (inflationary, cyclic, ekpyrotic, imaginary time, multi-verse, multi-world, hesitating, etc.) rely on geometry - i.e. there is always a beginning.
Thus there was also a beginning of physical causation, an uncaused cause. The only possible uncaused cause is God.
Or one of those maniacs who used "Godtoldme" to explain their genocide.
I mean specifically that you can't *calculate* this value and you can't *observe* this value. You *first* make an *assumption*(well several actually but I am simplifying), *then* calculate. The *assumption* comes *first*.
If you can't see that, then you can't see that.
Pray to Jesus that He heals your lame posts. Thank you.
You have just described Elsie's technique to a fault.
"You have just described Elsie's technique to a fault."
Stop using logic; it'll melt their brains.
Very few people have heard the voice of God telling them to be nice to their neighbors and even to their enemies.
Except Jake and Elwood.
You cannot *know* that daughter products were not present because you weren't there to *measure* it. It supposedly happened millions of years ago, how can you measure it? You can't.
And you can't apply current measures beyond the period over which they were measured (well 'scientists' do, but they shouldn't).
You *assume* and you *norm* and you *throw out* that which does not agree with your *assumptions*. Then you 'conclude' and claim that it is all so 'scientific'.
Dishonest from the beginning.
You speak as though you can say, with authority, that you have observed examples of both "common design" and "common ancestry" and therefore can accurately distinguish between the two.
Indeed I have. Not only have I "observed" examples of "common design", I have personally created quite a few of them. I am quite conversant with the design process, and what sorts of features designed objects will and will not have, and for what reasons, and what sorts of characteristic features will be found shared, and not shared, by things made by a common designer.
But, that is begging the question.
Maybe you are, but I'm not.
How can you know (when you study and observe a given set of organic beings) that you are looking at an example of common ancestry as opposed to an example of common design?
Because, as I've already pointed out, common design produces certain types of similarities and differences, which are quite distinct and recognizeably different than the types of similarities and differences which result in things which are produced by common ancestry. You clearly haven't bothered to read the links I provided -- these go into more specific detail on that topic.
You have already ruled out "common design"
No, I haven't. You are jumping to false conclusions based on nothing I've actually written.
(because it doesn't fit your evolutionary preconceptions).
Wrong again.
In your view, common design simply never occurs because you have already decided beforehand that no Designer exists.
No, you are yet again mistaking your *presumptions* for facts. You have either misunderstood my points, or are letting your own preconceptions get in the way of understanding them.
That only leaves the other option
No, I do not make the mistake of the fallacy of the false dichotomy. I have pointed out that there is *positive* evidence for common ancestry, nowhere have I committed the fallacy (so common among fans of "design") of thinking that I can "demonstrate" one explanation by trying to rule out some other explanation.
Are you actually reading my posts, or just posting your wild guesses about how someone "must" examine these issues?
(the only one you will accept)
Now you're just being obnoxiously insulting. No, that is not the case, and I have said nothing which would lead any rational person to that conclusion.
which is common ancestry.
I assert that there is positive evidence of common ancestry, because there is. Not only have you failed to deal with that issue, you have run around issuing baseless insults while utterly misdescribing my position, failing to address what I have actually said, and dodging having to deal with the actual evidence in any way.
Do you want to have an actual discussion, or do you just want to desperately issue insults so you won't have to think?
So I guess no matter what species we are talking about or looking at, we all know that we shall see the idea of common ancestry "proved".
You "guess" wrongly. I can only speculate as to whether the reason is your utter failure to understand the material, or your unwillingness to address it.
Come back and try again when you're ready and able to talk about something I've actually written, and not so quick to spew groundless insults in an attempt to console yourself about how anyone who arrives at a conclusion different than yourself "must" have gotten there by virtue of being a closed-minded idiot. I guess that's more comforting than having to deal with the fact that they might possibly have information that could challenge your desired conclusions, eh?
Without a doubt, Alamo-Girl!
What really drives me nutz about E. O. Wilson's statement is that he is saying evolution uses "illusions" to accomplish "ends" or "purposes" (reproductive success) while at the same time many if not most Neodarwinists strongly deny that nature has any purposes at all. What a jumbled mess!
Thank you so much for your kind words of encouragement Alamo-Girl! You can probably tell I've been doing a little thinking about "the observer problem" lately....
I'm especially wondering if you have an opinion on whether H. habilis, H. ergaster, H. erectus, and H. sapiens neanderthalensis were members of the ape-kind, human-kind, or (gasp!) transitional species, a.k.a. "missing links".
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.