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Author Topic:   Blood in dino bones
gengar
Inactive Member


Message 36 of 138 (194589)
03-26-2005 3:24 AM
Reply to: Message 30 by simple
03-25-2005 9:41 PM


Re: jar's little phrases
simple writes:
What I said was that blood and soft tissue would seem to fit a young earth scenario better than one where they died out 70 million years ago!
This level of soft tissue preservation would actually be almost as spectacular if the specimen really was only a few thousand years old. Decay processes usually destroy such things over timescales of days and months, so even if this dinosaur bone was as young as you'd like it to be some preservation mechanism is required to retain the blood vessels.
What you need is for it to be established that this mechanism is enough to preserve stuff for a few 1000 years but not enough for several million. Until then - maybe the Earth was created last Thursday, in a hurry, and a few mistakes were made!

This message is a reply to:
 Message 30 by simple, posted 03-25-2005 9:41 PM simple has replied

Replies to this message:
 Message 40 by simple, posted 03-26-2005 12:39 PM gengar has replied

  
gengar
Inactive Member


Message 43 of 138 (194682)
03-26-2005 1:46 PM
Reply to: Message 40 by simple
03-26-2005 12:39 PM


Re: stretching the evidence
I think you’re jumping the gun a bit here. The key question comes from one of your sources :
Do they consist of the original cells, and if so, do the cells still contain genetic information? Her early studies of the material suggest that at least some fragments of the dinosaurs’ original molecular material may still be present.
(my emphasis)
Although we have the preserved form of blood vessels and cells, it’s still not clear exactly what they’re now made of. Most fossilization processes result from some sort of mineral replacement or envelopment of the original material, and some scientists think that something of this sort has happened here. From the BBC version (quoting Dr Matthew Collins, who studies ancient bio-molecules at York University, UK):
"My suspicion is this process has led to the reaction of more resistant molecules with the normal proteins and carbohydrates which make up these cellular structures, and replaced them, so that we have a very tough, resistant, very lipid-rich material - a polymer that would be very difficult to break down and characterise, but which has preserved the structure,"
This would be pretty cool in itself. Again, you should realize that something of this sort would probably have to happen for preservation for any length of time beyond a few months (maybe years in ideal conditions — extreme cold or aridity for example).
So now all evos need to do is rewrite 'conventional wisdom'.
So? If our preconceptions get shot down by evidence, evidence wins. That’s how science works.
There is a big difference between 70 million years, and 100,000 years! Say some 69 million, 900,000 years! Talk about a stretch?
Of course. And it is possible (vanishingly unlikely in my opinion, but possible) that this find will rule out the 70 million year option. Ooh look, a potential falsification. I thought we didn’t have those

This message is a reply to:
 Message 40 by simple, posted 03-26-2005 12:39 PM simple has replied

Replies to this message:
 Message 45 by simple, posted 03-26-2005 5:34 PM gengar has replied

  
gengar
Inactive Member


Message 53 of 138 (194898)
03-28-2005 5:15 AM
Reply to: Message 45 by simple
03-26-2005 5:34 PM


Re: stretching the evidence
simple writes:
So you mean this could make false the radioactive dating, that gave those dates?
Not in the way you'd like, I suspect. If you could clearly establish that the preservation mechanism in this case could only operate over thousands of years and not millions, the hypothesis that this particular bit of bone is 70 million years old would be falsified. If the bone was clearly associated with Cretaceous strata, then you have to start asking questions about the dating of that stratum.
But the first 'if' in that paragraph is the big one. Best to go back to the actual article in Science rather than the news reports (I've given the link but it's subscription only I'm afraid):
Cortical and endosteal bone tissues were demineralized , and after 7 days, several fragments of the lining tissue exhibited unusual characteristics not normally observed in fossil bone. Removal of the mineral phase left a flexible vascular tissue that demonstrated great elasticity and resilience upon manipulation
My emphasis - these vessels were surrounded by minerals which have protected them from decay. What is interesting is that it had to have grown very fast around the vessels and cells to preserve them so well. Another contributing factor:
The unusual preservation of the originally organic matrix may be due in part to the dense mineralization of dinosaur bone, because a certain portion of the organic matrix within extant bone is intracrystalline and therefore extremely resistant to degradation
The blood vessels are found deep inside the bone, where there was apparently some mineralisation even when the dinosaur still was alive, which also would have helped preserve them.
So what it appears we have here is some kind of very fast mineralisation process isolating and preserving the soft tissue. It is the speed which is the issue: once the blood vessels have been enveloped, they will be well protected from decay, and could potentially survive a very long time - certainly much more than a few thousand years. Whether it could survive in its original chemical form for 70 million years is more of an issue, but from the commentary piece in Science:
Hendrik Poinar of McMaster University in Hamilton, Ontario, cautions that looks can deceive: Nucleated protozoan cells have been found in 225-million-year-old amber, but geochemical tests revealed that the nuclei had been replaced with resin compounds. Even the resilience of the vessels may be deceptive. Flexible fossils of colonial marine organisms called graptolites have been recovered from 440-million-year-old rocks, but the original material--likely collagen--had not survived.
In either case, the problem is that you can't just consider this find in isolation. At the moment you're dealing with a few isolated instances of extremely good preservation amongst the thousands of dinosaur bones found in these strata. On current knowledge, they are the exception rather than the rule - they are unusual. Would indications of young age require us to question our assumptions? Yes. Does it immediately invalidate the vast amount of evidence that suggests that dinosaurs and the rocks that bear them are very old? No.
This message has been edited by gengar, 28-03-2005 10:16 AM

This message is a reply to:
 Message 45 by simple, posted 03-26-2005 5:34 PM simple has replied

Replies to this message:
 Message 54 by simple, posted 03-28-2005 2:48 PM gengar has replied

  
gengar
Inactive Member


Message 61 of 138 (195641)
03-31-2005 3:25 AM
Reply to: Message 54 by simple
03-28-2005 2:48 PM


Re: stretching the evidence
simple writes:
What conditions normally would you think contribute to this happening? Since it is not normal with just rapid burial, I guess it likely would be something in the atmosphere, or dirt that it got trapped in?
But in a general sense, what we see is normal for rapid burial - that's the point I've been trying to make. Exactly the same processes (mineral envelopment and - probably - replacement) have operated on this fossil as on most others. In a specific sense, the exact chemistry is novel, and why is a good question. An obvious factor to investigate would be the pore fluid composition of the sediment it was buried in, which would be influenced by the sediment itself.
But don't be fooled - although the pictures look very impressive, the vessels didn't just fall out of the bone when it was broken open; they are the end result of dunking it in chemical bath for several days to remove the surrounding minerals.
Dating is only as good as an assumption that the decay process was always the same process. In other words only as good as saying there is nothing else but the physical world we now see, and it's current decay process. This is the assumption science makes, and one that cannot be proved or disproved. Something that cannot be proved or disproved is I would say, an unknown
Then, in reply to another poster, you said:
Yes, and my only assumptions about that is whether something different was happening in the past, not that what is happening, is happening.
I'm interested in your use of the word 'assumption' here. Yes, it is true that we are relying on constant rates of radioactive decay. But it's not like scientists have not tried to establish whether this is the case. Observations of distant supernovae, for example, show similar decay rates millions of years ago to those measured on Earth today. To get into this in detail is a little off topic, but you do realise that this 'assumption' has been tested and appears to be supported by evidence?
Meanwhile, you are also making an assumption - that things were very different only a few thousand years ago. Have you any evidence that this was the case?

This message is a reply to:
 Message 54 by simple, posted 03-28-2005 2:48 PM simple has replied

Replies to this message:
 Message 64 by simple, posted 03-31-2005 3:44 PM gengar has not replied
 Message 86 by Incognito, posted 04-04-2005 2:06 AM gengar has replied

  
gengar
Inactive Member


Message 92 of 138 (196638)
04-04-2005 9:11 AM
Reply to: Message 86 by Incognito
04-04-2005 2:06 AM


Re: stretching the evidence
Please educate yourself on the mega-fauna and mega-flora of the past. The last time I went down to the local lake I didn't see too many 60 foot cattails growing in the water...
You could educate yourself on the mega-flora and -fauna of the present. Why not head down the coast to California and look at the 360+ foot redwoods? Or take a boat and try and find a 100+ foot blue whale?
Or is the fact that everything seemed to be "bigger" not evidence of climate change at some point in the past?
Not as far as I know. In fact, as far as I'm aware, "everything" was not "bigger" in the past. Care to share your data?
I have to say I'm a little unclear on exactly what relevence your comments have to fossilisation of dinosaur soft tissue. That's what I've been talking about. I discuss the published results here. How does explaining that the blood vessels in question were encased in minerals, and that the original living tissue has probably also been chemically altered, represent a 'dodge'? That's what was observed.

This message is a reply to:
 Message 86 by Incognito, posted 04-04-2005 2:06 AM Incognito has not replied

Replies to this message:
 Message 93 by AdminNosy, posted 04-04-2005 11:05 AM gengar has not replied

  
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