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. That’s 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 Schweitzer’s 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 bone—the 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 hasn’t been discovered before is no right-thinking paleontologist would do what Mary did with her specimens. We don’t 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. “It’s 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, coldblooded—or both.
Meanwhile, Schweitzer’s research has been hijacked by “young earth” creationists, who insist that dinosaur soft tissue couldn’t 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, it’s not unusual for a paleontologist to differ with creationists. But when creationists misrepresent Schweitzer’s 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 Schweitzer’s 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 Horner’s 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 can’t be. Red blood cells don’t preserve.”
Schweitzer showed the slide to Horner. “When she first found the red-blood-cell-looking structures, I said, Yep, that’s 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 that’s not what they are.”
What she found instead was evidence of heme in the bones—additional 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 she’s 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, don’t go that way, she’s the kind of person who’ll 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 Harmon’s 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 helicopter’s capacity, so they split it in half. One of B. rex’s leg bones was broken into two big pieces and several fragments—just what Schweitzer needed for her micro-scale explorations.
It turned out Bob had been misnamed. “It’s a girl and she’s 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 they’re 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 that’s 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 dinosaurs—colorful, 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. “Y’all still need that lady ostrich?” The dead bird had been in the farmer’s 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 bone—but 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 couldn’t 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 vessels—the 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 question”—whether Schweitzer’s work is paving the road to a real-life version of science fiction’s 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. It’s 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, she’s 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 physiology—how 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 wasn’t 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. Schweitzer’s work is “showing us we really don’t understand decay,” Holtz says. “There’s a lot of really basic stuff in nature that people just make assumptions about.”
young-earth creationists also see Schweitzer’s work as revolutionary, but in an entirely different way. They first seized upon Schweitzer’s 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 Schweitzer’s research was “powerful testimony against the whole idea of dinosaurs living millions of years ago. It speaks volumes for the Bible’s 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. She’s 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 don’t need faith. I think he kind of designed it so that we’d never be able to prove his existence. And I think that’s really cool.”
By definition, there is a lot that scientists don’t know, because the whole point of science is to explore the unknown. By being clear that scientists haven’t explained everything, Schweitzer leaves room for other explanations. “I think that we’re always wise to leave certain doors open,” she says.
But schweitzer’s interest in the long-term preservation of molecules and cells does have an otherworldly dimension: she’s collaborating with NASA scientists on the search for evidence of possible past life on Mars, Saturn’s moon Titan, and other heavenly bodies. (Scientists announced this spring, for instance, that Saturn’s 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, it’s 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. “I’d much rather be out tromping around.”
“My eyeballs are just absolutely fried,” Schweitzer says after hours of gazing through the microscope’s eyepieces at glowing vessels and blobs. You could call it the price she pays for not being typical.
The Cambrian explosion has previously been thought to be the time of origin of multiple body plans and metazoan life. It used to be thought that the Mediacaran lifeforms were a sister clade. However, now several types of Precambrian organisms are thought to be ancestral to later forms, and we have fossils of metazoan embryos going back into the Precambrian.
"However, there is a growing body of evidence that many so-called vendobionts may actually belong to established metazoan phyla, although debates about the proper assignment of individual taxa continue. At the very least, we consider that there are strong arguments against the application of the vendobiont hypothesis to all the Ediacaran taxa (Gehling, 1991). The Cnidaria is almost certainly represented in the Precambrian (Conway Morris, 1993b). Amongst Ediacaran genera Spriggina has been interpreted as an annelid (Jenkins, 1992), Arkarua as an echinoderm (Gehling, 1987), and Parvancorina (considered again below) and Praecambridium (Jenkins, 1992) as arthropods. Other taxa have attracted more diverse speculation, Dickinsonia being variously interpreted as cnidarian, flatworm or annelid (see discussion in Valentine, 1992)."
Fortey, R. A.; Briggs, D. E. G.; Wills, M. A. "The Cambrian evolutionary ‘explosion’: decoupling cladogenesis from morphological disparity." Biological Journal of the Linnean Society (1996), 57: 13–33.
This is not saying that there was no Cambrian explosion, just that some major groups appeared earlier than that. The Cambrian explosion definitely was a dramatic event.
This next article I'd really encourage you to find, copy or print out, and read five times! I wish I could post the whole thing.
"Extant monophyletic groupings are always morphologically distinct from their extant sister-group, and that distinctness is brought about by subsequent extinction of the lineages (plus its offshoots) that led to each of them, away from their last common ancestor. As random extinctions through time slowly remove lineages, the most basal taxon of a clade will sometimes be the victim, thus widening the path-length between the surviving most basal members of extant sister clades (Fig. 3). The bases of clades are therefore eroded by extinction, and, as only living members of the clade can rediversify, this is a permanent loss. These extinct basal taxa will not possess all of the apomorphies that define the basal node of the surviving clade. It should be noted that this process will occur whether or not basal members of clades are particularly prone to extinction or not; there does not have to be anything ‘‘special’’ about basal taxa. One further aspect about these now extinct basal taxa is that they would have accumulated their own autapomorphies not possessed by the extant taxa. As a result, these basal fossil taxa are bound to differ from the extant clades: they will not be diagnosable as members of those clades; and they will show a confusing mixture of some but not all features of those clades, together with a set of features absent from them. It should be noted that this characteristic mix has been repeatedly noted in Cambrian fossils. For example, Hughes (1975) said of the Cambrian arthropod Burgessia: ‘‘what is apparent from this restudy is that Burgessia did possess a mixture of characters . . . many of which are to be found in modern arthropods of various groups’’ (Hughes, 1975, p. 434). . . .
"One example of the sorts of possibilities that stemgroup reconstruction offers is provided by the arthropods (e.g., Budd, 1998, 2001b). Optimization of the terminal character states of the various stem-group demonstrates the most parsimonious reconstruction of the evolutionary stages passed through by ancestral arthropods. A remarkably complete series is now available, demonstrating how the most basal, worm-like taxa of the entire Arthropoda sequentially acquired the important features characteristic of their clade, including the sclerites and lever-style musculature (Budd, 2001b), components of the biramous limb (Budd, 1996), and even how the complexities of the arthropod head were assembled (Budd, 2002), a construction that can be corroborated by the recent fauna (Eriksson et al., 2003)."
Budd, G. E. "The Cambrian Fossil Record and the Origin of the Phyla." Integrative and Comparative Biology, 43:157–165 (2003).
As I said before, we do have some deposits with excellent soft-bodied fossils, but these are the exception rather than the rule. As js1138 pointed out, we can tell that soft-bodied creatures (and creatures with other characteristics and from other environments) are under-represented in the fossil record by examination of fossils of living species and genera. Typical fossilization conditions preclude the preservation of details of soft flesh. Heck, we don't even need to check and see which modern organisms are missing or underrepresented in the fossil record, just look at the fossils that are available of hard-shelled and bony remnants. Trace fossilization of soft flesh around an organisms bones or lining its shell are extremely rare.
"TToE is supported by evidence"
Yawn. . .
"It doesn't require abiogeensis"
Duh. I know that. I never mentioned [sic] 'abiogeensis'.
"nor does it require observation (although we do have direct observation of micro-evolution)."
Yeah, that's the whole point. No one argues about what we have direct observation of.
I got 'em all OVER my yard!
(Ain't GOT no hair!)
Mention backing up again and you'll lose dinner!
`Twas brillig, and the slithy toves
Did gyre and gimble in the wabe:
All mimsy were the borogoves,
And the mome raths outgrabe...
But it still leaves one as master of his own domain.
"Beware the Jabberwock, my son!
The jaws that bite, the claws that catch!
Beware the Jubjub bird, and shun
The frumious Bandersnatch!"
I love Lewis Carroll :)
That was quite a non-post. Pretty standard in the CRIDer arsenal. But "No one argues about what we have direct observation of" is pretty funny. There are a LOT of scientific debates on gravity, string theory, DNA, etc. etc. etc.
You need to get out more and see what really happens in the world.
You are, of course, correct. We so-called "Evos" want to keep that separation in place. Somehow, CRIDers have the feeling that by debunking TToE (which is impossible given facts available to date), they somehow buttress Creationism (which is Faith-based) and make this wierd linkage that somehow understanding TToE makes one an athiest. And not just an athiest, but a God-hating, anti-Jesus athiest.
So we man the threads to keep disinformation and ignorance from creeping into our already-screwed up schools.
It is a thankless task but one we take on for future generations.
The authority of God is sui generis, and quite beyond human understanding. God is "beyond" spacetime reality and all categories of human thought. He is not subject to the order of creation which He created. There are some who say (as you do) that God is "vengeful," "inflicting infinite consequences" on human miscreants. To me that is a caricature; for God is Love, Truth, the Good, Justice -- at least these are the descriptors that a faithful Christian who responds to His call of love and grace attaches to Him. Perhaps your understanding of the JudeoChristian tradition is a tad superficial, King? Have you ever really bothered to "study" it? Or ever allowed yourself to be drawn by God's love for you?
In short, I think some of your assumptions may not be too well founded. Which maybe is why we're having such a difficult time understanding each other. For one thing, I don't know what in the world you want me to "try again." Please be more specific, King!
Thanks for writing!
Well said, hosepipe. Your insight about Iraq seems quite on the money to me. Thank you so much for writing!
I hope you don't mind me jumping in on your conversation, but I wanted to comment on the above.
I concur with your assertion that God isn't vengeful, but probably for much different reasons. One of those reasons is that I disagree that God is not subject to order, and I also disagree that God is beyond space-time. My personal feeling is that God is subject to order because God IS order, and God is not beyond space-time, but rather underlies it. I sometimes think that both religious philosophers seeking to determine the nature of God and scientists seeking a "Theory of Everything" are stumbling towards the same goals. I believe that the reason things work the way they do is because we have a fundamental order to the universe, perhaps someday identifiable as God.
I think I came to this conclusion after a summer intensive course in Dante. I was reading Sagan's "Contact" concurrently with studying the Divine Comedy. We were discussing the means by which souls arrive in hell, according to Dante, and had come to the conclusion that the Inferno suggests not vengeance, but a certain degree of determinism. That is, similar perhaps to binary code, if you are at 0 when you die, you go to heaven, or if you are at 1, you go to hell. Your own actions determine your setting. Of course, it's more complicated than that, but that's the gist.
Between that and Sagan's idea that messages have been embedded in numbers like Pi got me thinking that maybe the numbers aren't the signifier, but the actual signified. The reason that things like evolution of species (to segue briefly back to the topic of this thread) work so beautifully is due to the fundamental order of things that holds the universe together. An order that I do not believe was created by God, but that actually is God.
Anyway, that's my two cents.
Further cross-check assumptions such as the constant rate of atomic decay and constant lightspeed by observing atomic decay rates in distant supernovae.
Thank you very much for your post #1276...you have quite concisely, approached God in a manner that was lovely...it will take me some time to let it sink in, but I do believe what you have stated, is something I could well embrace...
It may be just your two cents worth, as you say, but heck, I think those thoughts are worth a million bucks...
Thanks :)
Such a thing is an impossibility.
That the impossible does not occur, is neither an argument for evolution, nor an argument against anything else.
Sexual reproduction, in and of itself, does not infer evolution, and to suggest that it does is simply absurd...like it or not.
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