While doing a little reasearch for a rather idiotic religion thread i came across a website saying that the theory that dinosaurs were wiped out by an astroid impact is not widely accepted before. Ive never heard anything like this before but I think its fairly convincing and Id like to see what other people think: http://www.livingcosmos.com/k-t.htm

Okay, first thing, it's promoting a book. This doesn't invalidate the ideas, but it's usually a warning. That said, I'll list the things I'm skeptical about. Doesn't mean they're wrong, simply means they send up red flags to be investigated more.

1) "The impact was supposed to be the site of Chicxulub, Yucatan, and now a multi-ringed crater is noted in the North Sea of approximately the same age. Yet, the Southern Hemisphere was just as devastated as the Northern Hemisphere."
The impact possibly could have set off the Deccan Traps in India, then I believe south of the equator and opposite the impact site. That, plus I don't believe the equator is as good a protector as once believed from global atmospheric disasters.

2) "The site of the proposed impact at Chicxulub, Yucatan, as part of the Caribbean Plate, was undergoing uplift, and plate rotation from the Pacific to the Atlantic during the Cretaceous, which is extremely difficult to reconcile with an impact."
Not sure why this would matter.

3) "Recent well coring at the Chicxulub (e.g., well log No.6) indicates that the structure may be volcanic or a cryptoexplosive geobleme (a structure caused by an explosion ejection from the Earth)."
Fair enough, but was that only one site? Hell of an ejection if that's true, but recent discoveries about places such as the Yosemite area would make me accept a buildup and eruption possible. However there's a lot of evidence to point to impact.

4)"Iridium is found almost globally and is found in strata that is not the same date everywhere, when it should be found mostly in the Yucatan region and bare the same date. The greatest abundance of iridium was found on the Hess Rise in the mid-Pacific, some 10,000 kilometers (6,200 miles) away from Chicxulub. In Raton Basin, New Mexico, the iridium was deposited during normal polarity of the geomagnetic field, not the reversed polarity of other sites. Many irregularities in iridium occur worldwide (by orders of magnitude)."
Last I read the iridium ages were very close in all areas found. It was the original smoking gun or extraterrestial origin of a global scale, and pointed to that single age. Maybe something new...?

5) "Some evidence indicates that the shocked quartz did not originate by impact, but may be volcanic or tectonic in origin."
Mentioned elsewhere about the Deccan
Traps, the site says that volcanic shocked quartz would be larger in size that impact, and be localized. However, the shocked quarz found accompanying the iridium layer globally is consistant with impact sizes.

6) "Some areas, such as at Gubbio, Italy, display a long interval of shocked minerals which is bisected by the boundary. Also at Gubbio, there are five iridium peaks, indicating the need for five impacts, and therefore, five craters with no other impact structure of the right age (with the possible exception of Manson Crater in Iowa). Similar extended zones can be found in the Pacific, Atlantic, Denmark, Spain, France, Germany and New Zealand."
Multiple impacts maybe. And craters are hard to find, look how long it took to find Yucatan's, as big as it is.

7)" In most situations the iridium and other noble metals are associated with organic compounds (kerogen and organic carbon or coal) from dead biomass, which is likely to be the source of the metals."
I thought iridium was rare on earth, period.

8) "The abundances of noble metals is more consistent with earthly compositions than extraterrestrial sources at many sites. Also other metals typical of meteoritic materials are missing in some sites with iridium or the ratios are not typical of impact debris. Moreover, the shocked quartz at some sites is more consistent with water transport (ocean erosion) rather than atmospheric (as would occur with impact)."
Not all meteors are the same. We're not experts on meteor consistance anyway, that's wht the NEAR mission was so important. And the impact was in water, with the resulting surge out and back into the crater. Could this account for what's found?

9) "Other times of impact did not cause such extensive mass extinctions."
Actually I think there's correlation in a few cases, the few big impacts we know of. The rest could be other factors, or lost evidence. 65 million years is relatively recent, and look how much debate it's causing.

10) "An impact is theoretically less likely to initiate widespread tectonic activity, and sea level rise, which occurred at the end of the Cretaceous."
Lot of energy, directed through the earth. Who's to say what will happen? How much experience do we have with impacts? Look at what happened on Jupiter, and that was a small comet, not solid. Actually, a solid might not have made as much of an explosion, but anyway...

11) "The climatic shift should have went from a drastic drop in temperature (with sunlight blocked) to progressively hot temperatures (the Greenhouse Effect). "

Not sure on this one myself.

12) "The mass extinctions of the time do not fit the impact theory: (a) The extinctions were not instantaneous and were selective. (b) Many species were in decline before the time of the proposed impact. (c) If the Yucatan region were the impact site then the greatest mass extinctions should be in southeastern North America, Central America, and northeastern South America, but were not (it seems that the greatest dinosaur fossil graveyard is in the Gobi Desert, on the other side of the Earth, and most extinctions were along mid-latitudes, not the tropics). (d) The huge dust and water vapor cloud should have caused plant extinctions the most, but it did not, and equatorial species should have been hit the worst, but it was mid-latitude species that were affected the most, and most mass extinctions were animals. (e) Photosynthetic nannoplankton survived into the Tertiary, and Cretaceous and Tertiary species even coexist in land-based marine sections of the Tertiary. (f) Tropical insects should have become extinct, but persist into the Tertiary. (g) The dinosaurs appear to have undergone gradual extinction in at least some locations."
Some good question here, I'd have to research more to argue them. One thing, "The extinctions were not instantaneous and were selective", one of the arguments for the theory this site pushs is why some fossils have been found in the opposite, suddenly killed, in mid battle for one. It's arguing both sides it seems. Wouldn't a shockwave moving at the speed of sound, plus the sudden heat blast, instantly kill those exposed?

13) "High-energy terrestrial explosions, called geoblemes or cryptoexplosions, have not been studied, nor have laboratory simulations been tested. Therefore, much of the evidence for impact is somewhat biased by not considering the evidence in light of all the possibilities. For example, a number of journal articles have shown that the craters on Mars and other planets are dynamically related to the core, and therefore, are internal in origin. Also, the structural similarities of multi-ringed craters with a central peak are too uniform, regardless of size and proposed angle of impact, for them to be impact craters; laboratory experiments show different structures for different angles and impactor size. This suggests that multi-ringed craters with a central peak, like that of the Chicxulub, are internally produced."

There are craters such as this on the Moon, which is dead. I thought the argument of craters being volcanic had been done away with years ago.

That's enough (probably too much) for now. What evidence of radiation deaths is there among dinosaurs anyway? That seems to be the biggest argument going for this theory, but how do you preserve evidence of this?

The meteor hit off the coast of the Yucatan Peninsula in Mexico and spread out a layer of ash that covered the entire earth's atmosphere, blocking out the sun's photons and ultraviolet rays. This caused the extinction of the dinosaurs except for birds (Aves) and Crocodylians that still survive today.

While doing a little reasearch for a rather idiotic religion thread i came across a website saying that the theory that dinosaurs were wiped out by an astroid impact is not widely accepted before. Ive never heard anything like this before but I think its fairly convincing and Id like to see what other people think: http://www.livingcosmos.com/k-t.htm

I gather you mean "was not widely accepted before"?

Perfectly true, in fact the chap who originally proposed the idea was thought fanciful in the extreme by the the establishment at the time... Funny how times change, eh? ;)

Most, pre-impact theories, attributed the mass extinction of 65 million years ago as being down to the cumulative effects of the basalt larva planes that had been pouring forth for millions of years leading up to the event - the cumulative effects of all that sulphur dioxide pouring unchecked into the atmosphere changed both climate and atmospheric composition.

This was an ongoing catastrophic event which had been going on for a very long time with cumulative effect.

These days the Impact, though widely accepted as being part of the larger picture, is thought of more as being probably the last nail in the coffin of the Dinosaurs, more than the actual coupe de gras...

Possibly, if the meteor hadn't have happened life for them may have continued for another few million years yet - but basically the world was becoming an increasingly hostile place for all forms of life - Dinosaur species were becoming extinct throughout this period purely through this already ongoing mass extinction level event provided by dear old mother Earth leading up to the ELE meteor impact so, the establishment still ended up getting their own way with the argument.

About the same time dinosaurs became extinct, mammals elvolved out of the same phylogentic clade called Amniota that dinosaurs (Archasauria, originally Diapsida) evolved from. The animals left on earth were then mammals and other Reptilia (turtles, lizards, crocodiles, birds and other reptiles, and of course aquatic life and arthropods (insects, spiders). Do we know what mammals made their way through this massive extinction, i.e., in what form or species they were at that period of time, that led to homo sapiens?

About the same time dinosaurs became extinct, mammals elvolved out of the same phylogentic clade called Amniota that dinosaurs (Archasauria, originally Diapsida) evolved from. The animals left on earth were then mammals and other Reptilia (turtles, lizards, crocodiles, birds and other reptiles, and of course aquatic life and arthropods (insects, spiders). Do we know what mammals made their way through this massive extinction, i.e., in what form or species they were at that period of time, that led to homo sapiens?

Mammals evolved well before the dinosaurs became extinct, although while the dinosaurs were the dominant vertebrates, mammals were probably small & nocturnal. Incidentally, mammals are synapsids while dinosaurs & birds are diapsids - the names refer to the number of openings in the bones overlying the cranium.

I did read that the mammals back then were small, like rodents, but I don't think that in relative terms that mammals evolved way before dinosaurs. Also there seems to be a confusion as to whether mammals evolved directly from reptiles, but current phylogeny shows that they evolved from the same "ancestor" of reptilia. But I wonder if both of these could be mistaken and that mammals developed from a totally different lineage after fish came on shore and developed into tetrapods.

1) Why only the dinossaurs died, but not mammals? Is there any relation with the fact that mammals are "hot blood" (i dont know how do you say this in english) animals?

2) Which i sthe most acceptable theory, actually, about the extinction of dinossaurs? Still be the same about the meteor?

I have some questions I havent been able to find answers for:

How long did it take for dinosaurs to die out? How long was the atmosphere blocked out from the impact debris cloud? What kinds of birds were around at that time?

Hot blooded animals are called endotherms because they are dependent on the heat production generated from their own bodies.

Cold blooded animals, like reptiles and amphibians, are called ectotherms because their body temperature is dependent on the heat of the environment.

This is an excellent point. Since dinosaurs are thought to have all been cold blooded, evolving from reptiles, they would have been the most likely to die out because when the earth was covered over by the debri and particles from the meteor blast, this blocked out the sun light and caused the earth's atmosphere to become cold. Small mammals and aquatic life would have had a better chance of survival since they could still generate their own heat. Many of these small mammals were probably burrowing rodents, so they could also keep warm by living in underground nests.

I have some questions I havent been able to find answers for:

How long did it take for dinosaurs to die out? How long was the atmosphere blocked out from the impact debris cloud? What kinds of birds were around at that time?

I'm not sure if we'll ever know the exact answer to these questions, although I'm sure some scientists could estimate it. How long it took for the extinctions to take place would depend on the amount of atmospheric cover blocking out the sun's rays, which life died out first, loss of their food source (plants had no sunlight for photosynthesis and would have died out, thus no food for herbivores), and the animals location.

We do know that the thickness of the layer of ash left over from the meteor impact off the coast of the Yucatan Peninsula decreases from the distance of its impact. The impact also generated massive tidal waves - nothing comparable to what you see today - that would have completely and almost instantaneously wiped out any land-dwelling terrestrial life within a few hundred miles of the impact area. Then came the covering of the upper layer of the earth's atmosphere with the ashes that blocked out the sunlight. Winds would've carried it around the world, probably for weeks, months - hard to say how long. And even harder to say how long this would have affected the lowering of the earth's temperature.

This may be surprising to some of you but you should also know that within the 4.5 billion year history of the earth, we have undergone "five" mass extinctions, but because the meteor 65 million years ago was the most recent, this is the one we all talk about!

Since life evolved on earth 3.86 billion years ago, about 99.9% of the total animal species that have ever existed on earth are now extinct. And for most of those species, we have no idea what they were or what they looked like because there are no fossils to show them. Think about what we imagine as extraterrestrial. Fossils usually only form when there is cartilage or hardened bone-like material to preserve them, and only under the right conditions to preserve it. Most of the animals in early life forms had no hard material substances to even be preserved. It is estimated that if every person in North America were to be wiped out by some natural force, only three fossils of all these people would remain to "somehow" be found.

1) 65 million years ago: 76% of species disappeared from the meteor impact off the coast of the Yucatan Peninsula in Mexico.

2) about 206 million years ago: a large meteor crashed into Quebec, Canada wiping out 65% of the species on earth at the end of Triassic period.

3) about 250 million years ago: a large meteor crashed into Northwestern Australia, with a massive outflow of lava and the extinction of about 96% of the world's animal species.

4) 355 million years ago: two large meteorites hit Nevada and Western Australia possibly causing the extinction of 75% of the world's species. Scientists are still uncertain about the exact cause.

5) about 443 million years ago: massive glaciers formed causing sea levels to drop 50 meters and ocean temperatures to drop resulting in the extinction of 75% of all animal species.

Therefore only about one tenth of one percent of all animal forms that ever existed on earth still exist today in one form or another (0.1%).

Valich, you are being somewhat disingenuous by suggesting that the meteorites as the cause for three of the four mass extinctions before the KT event [even considering the caveat of 'possibly' in one case.] We do know there were extinctions. The causes are nowhere near as well established as the KT event, and frankly, as you yourself have noted this may have only been the final nail in the coffin.
The truth is one of the more interesting problems facing geologists at present is the cause and the character of these earlier mass extincitions. You might like to add a sixth, namely the one we are undergoing at present. And a seventh when the oxygen being pumped into the atmosphere by cyano-bacteria two or three billion years ago wiped out most of the earlier species. Or the decimation that must have accompanied each Snowball Earth episode.

Well I guess I should take that as a compliment as I certainly never claimed to be anything close to a genius, but I don't follow your point about "the final nail in the coffin" bit.

Each time there was an extinction, the diversity of species on earth rebounds - sometimes at a tremendously rapid rate. We know of these other extinctions because of the layers of ash that have been found within the layers of shifted or collapsed geological formations, like what happens in earthquakes. Or by reading these layers through the wearing down of the side of a cliff by a natural cause, like how the Colorado River formed the tall cliffs that make up the Grand Canyon. And we know that the species became extinct and then other species rebounded at a given rate through fossils and through carbon isotope dating. We can determine temperature and oxygen levels at different times in history because of the molecular makeup and oxygen concentration that we know of from the deep soil deposits we have drilled out and the ice layer contents that are being drilled in Russia and in the Arctic.

I certainly do agree with you that mankind is now providing the earth with another extinction - possibly even the worst one ever! And yes, when cyanobacteria liberated the way for aerobic life to evolve and florish on the earth by their production of O2, then there had to be a corresponding decline in the previous anaerobic life on earth. But because these unicellular prokaryotes lacked any cartilage or bones (endoskeleton or exoskeloton - hard outer layer, like a shell), they left no fossil traces.

My apologies. I thought you had written that the Chicxulub impact may have been the final nail in the coffin for the dinosaurs, which I could agree with. I am not yet wholly convinced that this alone can account for their demise.
I am certainly very far from convinced that any of the earlier extinction events are related to impacts. You are being rather optimistic in suggesting that we have solid evidence to support these events. I don't even buy (yet) the alleged Permo-Trias impact evidence.
You note that the prokaryotes left no fossil traces. One might add apart from the massive numbers of stromatolites found, I think, on every continent throughout much of the Pre-Cambrian.

And stromalites are very beautiful structures at that: proof of the evolution of cyanobacteria. Some stromalites are living stromalites while others are fossils, so you're right, in some case they leave strange fossil evidence. Had cyanobacteria not be alive today though, how would we know what these fossilized striated forms are? Perhaps only geological anomalies.

I am not a scientist so I have not participated in any excavations or research on the previous extinctions but this is what is being written down in many textbooks as fact and I haven't heard of any researchers going out there trying to disprove them. Although I did take a geology course and our professor did point out to us the most recent ash layer (65 mya) and evidence of where the glaciers stopped and then receded in North American after the last ice age. You could see a clear line of large boulders extending throughout fields on-and-off over a fifty mile distance that abrubtly ended when they began to recede.

Had cyanobacteria not be alive today though, how would we know what these fossilized striated forms are? Perhaps only geological anomalies.What has this to do with the price of bread? You stated that prokaryotes left no fossils. I corrected you. Your enthusiam for the field of Earth Science is very clear and I applaud it. You will understand, I think, that it is helpful to others reading these threads if the facts, as far as possible are indeed facts. I have noticed a couple of occasions where your enthusiasm seems to have outstripped your research. I hope you will not take it amiss if on those occasions I seek to correct you. Naturally you are free to return the favour.

but this is what is being written down in many textbooks as fact and I haven't heard of any researchers going out there trying to disprove them.Please cite a single textbook in which the mass extinctions,other than the KT boundary event, you list in yesterday's post are attributed exclusively or primarily to bolide impact.

You really do have sharp mood swings that are counterproductive to rational scientific enquiry and learning.

You note that the prokaryotes left no fossil traces. One might add apart from the massive numbers of stromatolites found, I think, on every continent throughout much of the Pre-Cambrian.

I mentioned that anaerobic prokarytes left no fossil traces - though I may be wrong. If so, please correct me. The cyanobacteria that form stromatolites are considered aerobic bacteria.

You're other question about the previous mass extinctions:

"Five major mass extinctions have been identified, the most severe of which occurred at the end of the Permian Period, approximately 250 million years ago, at which time more than half of all families and as many as 96% of all species may have perished. The most famous, and well studied extinction, though not as dramatic, occurred at the end of the Cretaceous Period (65 million years ago), at which time the dinosaurs and a variety of other organisms went extinct. Recent studies have provided support for the hypothesis that this extinction event triggered by a large ateroid which slammed into the earth, perhaps causing global forest fires and obscuring the sun for months by throwing particles into the air. This mass extinction did have one positive effect, though; with the disappearance of dinosaurs, mammals, which previously had been small and inconspicuous, quickly experienced a vast evolutionary radiation, which ultimately produced a wide variety of organisms, including elephants, tigers, whales, and humans."

from "Biology," by Raven, Peter H. and George B. Johnson, 6th edition
(International Edition), 2002, page 473.

William K. Purves, et. al.'s book "Life: The Science of Biology," 7th edition, 2006 also has a nice chart summarizing these five extinctions on pages 444-445 along with charts that show the sea level, oxygen concentrations, earth's temperatures and glacier periods throughout history from the PreCambrian Period right up until the present. These charts are useful in comparing these mass extinctions with other environment changes that occurred at the same time.

Valich,

You really do have sharp mood swings that are counterproductive to rational scientific enquiry and learning.

I don't think so. I think he's just realized that you seem to copy and paste a lot of stuff into your posts that aren't always relevant (and are often shown to be incorrect or misinterpreted.) I've gathered a viewpoint of you as someone who wants to appear to be really knowledgeable, but is, in fact, googling for a lot of it.

This forum isn't about showing off copy and pastes or our google skills. It's about open and honest discussion. (Hey. At least you're not ressurecting dead threads like you were. Your name is still stretched out thee pages long though...)

Anyway.

"Five major mass extinctions have been identified, the most severe of which occurred at the end of the Permian Period, approximately 250 million years ago, at which time more than half of all families and as many as 96% of all species may have perished. The most famous, and well studied extinction, though not as dramatic, occurred at the end of the Cretaceous Period (65 million years ago), at which time the dinosaurs and a variety of other organisms went extinct. Recent studies have provided support for the hypothesis that this extinction event triggered by a large ateroid which slammed into the earth, perhaps causing global forest fires and obscuring the sun for months by throwing particles into the air. This mass extinction did have one positive effect, though; with the disappearance of dinosaurs, mammals, which previously had been small and inconspicuous, quickly experienced a vast evolutionary radiation, which ultimately produced a wide variety of organisms, including elephants, tigers, whales, and humans."

You'll notice that this paragraph you quoted refers to the KT event. The KT event is the only which has been proven to be caused by a meteoric impact. The other extinction events don't have the same evidence. There are conjectured theories that perhaps certain impact craters were from the same general time period and that perhaps they had a part to play in them, but only the KT event has the world-wide layer of iridium (I think it's world-wide. I'm sure that Ophiolite would know the answer to that. This is his area of expertise, after all.)

The others are theoretical without this evidence. Highly theoretical. And if your textbooks are teaching them as more than theoretical then your textbooks are wrong. I think that the fault might be either in your own misinterpretation of what the textbooks are teaching (that meteoric impacts might have played a role but that the case is not closed) or that your teachers have. I've known several teachers in my time that have vastly misrepresented their curriculum due to their own ignorance. Some even outright confabulated (baldfaced lies.)


quelquechosedautre,

Shutup.
Aren't you the douchebag who was posting garbage about who really built the pyramids or some other pseudo crap a while back? If so, go away.

"The fossil record also shows that, of all organisms that have ever lived, only 1% survive today. All others are extinct."

from "Ch. 10 Evidence of Evolution."
http://www.whps.org/schools/hall/departments/science/Biology/Documents/Chapter%2028.doc

"Stromatolites have been described from various units in the Archaean but their cyanobacterial origin is hard to prove and even their biogenic origin is often controversial - many could also have been formed abiogenically by rapid marine precipitation of aragonite or by hydrothermal precipitation of barite and chalecdonic quartz."

from "HOW OLD IS AEROBIC PHOTOSYNTHESIS? A FRESH LOOK AT THE FOSSIL EVIDENCE," by BRASIER, Martin D., 2001.
http://gsa.confex.com/gsa/2001ESP/finalprogram/abstract_7831.htm

"The oldest known structured fossils are most likely stromatolites. Believed to be formed by the entrapment of minerals by mucous-like sheets of cyanobacteria, the oldest of these formations dates from 3.5 billion years ago. Fossilized deposits of heavy carbon (acritarchs) that are also indicative of earlier life (3.8 billion years ago) are currently proposed as the remains of the earliest life on Earth."

from "Fossil", in Wikipedia
http://en.wikipedia.org/wiki/Fossil

"Scientists have fossil evidence of bacterial life on Earth ~3.8 billion years ago. At this time, the atmosphere of the Earth did not contain oxygen, and all life (bacterial cells) was anaerobic. However, About ~3.2 billion years ago, fossil evidence of photosynthetic bacteria, or cyanobacteria, appears. These bacteria use the sun's energy to make sugar. Oxygen, released as a waste product, began to accumulate in the atmosphere. However, oxygen is actually pretty toxic to cells, even our cells! As a result, anaerobic cells were now a disadvantage in an oxygen-containing atmosphere, and started to die out as oxygen levels increased.

Aerobic bacteria appear in the fossil record shortly after that (~2.5 Billion years ago). There cells were were able to use that 'toxic' oxygen and convert it into energy (ATP) and water. Organisms that could thrive in an oxygen-containing atmosphere were now 'best suited to the environment'. Aerobic eukaryotes appear in fossil record shortly after that, (~1.5 billion years ago). These cells contain either mitochondria, or both mitochondria and chloroplasts. The mitochondria and chloroplasts have their own genomes, but can not live outside their host cell."

from "The Endosymbiotic Theory," IUPUI Dept. of Biology, February 18, 2004
http://www.biology.iupui.edu/biocourses/N100/2k4endosymb.html

"" - Early cells arranged in a filament at Warawoona, 3.5 BYA (billion years ago).
- Stromatolites (mounds of photosynthetic cyanobacteria) 2.7 billion years old.
- Intact stromatolites present today in Shark's Bay." (Western Australia)

from "Origins of life," lecture notes by Bruce Walsh, University of Arizona, 1995.
http://nitro.biosci.arizona.edu/courses/EEB105/lectures/Origins_of_Life/origins.html

Life on earth originated about 3.86 billion years ago. Aerobic organisms (life that requires an oxygen environment) evolved about 3.2 billion years ago. Since we have fossil evidence dating back 3.5 billion years ago, then this fossil evidence might be anaerobic (from life that does not require an oxygen environment. Oxygen started to accumulate in te environment 3.8 billion years ago, but at very extremely small concentration levels - nothing like the amount of oxygen in the air we breath on earth today. So I guess its up for debate whether or not this life was aerobic or anaerobic.

[QUOTE=invert_nexus]Valich,

I don't think so. I think he's just realized that you seem to copy and paste a lot of stuff into your posts that aren't always relevant (and are often shown to be incorrect or misinterpreted.) I've gathered a viewpoint of you as someone who wants to appear to be really knowledgeable, but is, in fact, googling for a lot of it.

This forum isn't about showing off copy and pastes or our google skills. It's about open and honest discussion.....I think that the fault might be either in your own misinterpretation of what the textbooks are teaching (that meteoric impacts might have played a role but that the case is not closed) or that your teachers have. I've known several teachers in my time that have vastly misrepresented their curriculum due to their own ignorance. Some even outright confabulated (baldfaced lies.)"

Examine his other posts and you'll definitely see the mood swings: sometimes extremely polite, then seconds later an outburst of agressive hostility.

I'm not trying "to appear" in any way at all, or trying to paint this-or-that type of picture of "myself." We're searching for and trying to get at the facts. In his last post, he asked me to provide a textbook source and that is what I did. Your painting a picture of YOURSELF right now as someone who wants to appear as being more knowledgeable than what is printed in textbooks and more correct than teachers, of whom you say have "vastly misrepresented their curriculum due to their own ignorance." I no of no such cases of "misrepresenting the curriculum." Do you know what a "curriculum is"? I know of teachers that have been wrong in their views and stated incorrect facts, but none that I have have taught geology when the curriculum was physics, etc.

If I just post what is written in the textbook, as above, or a small quote from a huge long article, then you certainly cannot accuse me of "your own misinterpretation of what the textbooks are teaching" as you are doing right now! So now I am avoiding your false contemptuous accusation and am providing clear, straightforward, scientifically reviewed and substantiated evidence.

But because these unicellular prokaryotes lacked any cartilage or bones (endoskeleton or exoskeloton - hard outer layer, like a shell), they left no fossil traces.

You might be interested to learn that there are plenty of fossils found that have no hard body parts. The conditions for fossilization are rare but not impossible. The Burgess Shale is the most well known of these 'mother lodes'. However, much is coming out of China these days.

In his last post, he asked me to provide a textbook source and that is what I did.

I know he did. I'm not talking about that. I'm talking about all the posts where you've copied and pasted LOTS of stuff that doesn't always say what you think it says. Charonz' comments to you in that Urey/Miller thread for instance. Frankly, I noticed this about you from the start and was part of what made me interject into your original ressurection spree.

Your painting a picture of YOURSELF right now as someone who wants to appear as being more knowledgeable than what is printed in textbooks and more correct than teachers, of whom you say have "vastly misrepresented their curriculum due to their own ignorance." I no of no such cases of "misrepresenting the curriculum." Do you know what a "curriculum is"? I know of teachers that have been wrong in their views and stated incorrect facts, but none that I have have taught geology when the curriculum was physics, etc.

Oh shutup.
You're being a douche bag now because I've hurt your feelings.
"Duh der. You don't know what curriculum is. You're a stupid twit because you don't use proper English. Grammar grammar grammar."
Do you realize just how idiotic that response was?

Now. What did I mean? Perhaps I used curriculum incorrectly. Who gives a shit? The point was plain. I've known a lot of teachers who blew smoke out of their ass on a daily basis.

However, I don't think that I did use the word incorrectly.
"A group of related courses, often in a special field of study: the engineering curriculum."
Therefore, a teacher can teach a series of courses in a particular curriculum. If this teacher is a liar who likes to blow smoke out of his ass to appear more knowledgeable than he is, then he is misrepresenting his curriculum. I.e. he is teaching falsehoods as truths in his curriculum. Thus he is misrepresenting his curriculum.

Douche bag.
You're new to the internet aren't you?
Grammar patrol is a poor defense.

As to me trying to appear more knowledgeable than teachers and textbooks. No. With the teachers, it generally didn't sink until much later just how much they were lying. To the young and impressionable, their act carries itself well. It is only with later maturity and more education that one begins to realize the depths of the lies that certain teachers told.

And as to textbooks. I already showed how the textbook you quoted only referred to the KT event. I'm not talking shit on the textbook, but rather your interpretation of it (or your teachers (that was your out, but you decided to take offense instead... your call.)) The problem wasn't with the textbook but rather with your interpretation that it is a 'fact' or even a 'reasonable assumption' that most of the extinction events were caused by (or even accompanied by) meteoric impacts.

If I just post what is written in the textbook, as above, or a small quote from a huge long article, then you certainly cannot accuse me of "your own misinterpretation of what the textbooks are teaching" as you are doing right now!

Whatever, douche. I'm just trying to help you to stop appearing so foolish. You've said stupid shit so much that it's getting old. You keep getting called on it and then you just go digging for more copy and pastes. Don't take my advice then. Whatever.

So now I am avoiding your false contemptuous accusation and am providing clear, straightforward, scientifically reviewed and substantiated evidence.

Then how come you're wrong so much?


Edit:
Oh. And before Ophiolite jumps my shit: "The KT event is the only which has been proven to be caused by a meteoric impact."
Proven is a bit strong here. I'll admit. It's still controversial and probably always will be. However, there is lots of evidencet that a catastrophic impact did occur and that it had wide-scale effects, even if it was, as was said earlier, 'the final nail in the coffin'.


The extinction event I'm interested in is the Permian-Triassic where it has been shown that oxygen levels in reached a nadir followed by a peak which coincided with the existence of the largest of the dinosaurs...

Valich,
The other extinction events don't have the same evidence. There are conjectured theories that perhaps certain impact craters were from the same general time period and that perhaps they had a part to play in them, but only the KT event has the world-wide layer of iridium (I think it's world-wide. I'm sure that Ophiolite would know the answer to that. This is his area of expertise, after all.)

The others are theoretical without this evidence. Highly theoretical. And if your textbooks are teaching them as more than theoretical then your textbooks are wrong. I think that the fault might be either in your own misinterpretation of what the textbooks are teaching (that meteoric impacts might have played a role but that the case is not closed) or that your teachers have. I've known several teachers in my time that have vastly misrepresented their curriculum due to their own ignorance. Some even outright confabulated (baldfaced lies.)


quelquechosedautre,

Shutup.
Aren't you the douchebag who was posting garbage about who really built the pyramids or some other pseudo crap a while back? If so, go away.

If you look at all my postings on this forum, only the last two were cut and pasted quotations - as requested! But in any case, you're contradicting yourself. You're criticizing me for possibly misinterpreting what is written in the textbooks, and then you're criticizing me for posting what is written so that the original writtings can be objectively interpreted by everyone.

Iridium deposits were also found in the late Devonian extinction (~350 million years ago). But meteors are not the only causes of the previous mass distinctions, nor are iridium deposits. Scientists look at the sudden stop in fossil evidence for the diversity of so many species, plate tectonics, sudden drops in global temperatures,sea level changes that at times covered the earth, carbon isotope changes that indicate organic productivity, abnormalities in quartz crystal structure that indicate "shock" events like that of a sudden meteor impact, lava flows from volcanic activities, and, as in the case of the late Permian extinction (250 mya - the largest extinction in earth's history) the sudden loss of accumulation of sedimentary carbon deposits that lasted for 6 million years. In other words, for 6 million years their was a sudden absence of organic matter decomposition that is compressed under pressure and temperature in deposits to form carbon. This is a clear indication of a massive extinction. During this extinction their is evidence of a sudden increase in the earth's temperature, probably caused by massive outbursts of lava eruptions through plate tectonic cracks, as is evidence from the huge lava flows around long plate tectonic adjacent areas.

I've received a lot of compliments from other members on other forums for providing web links and quotes. And yes I have been participating in forums for about six years now. Most of the other ones were medical forums so they involved folks with a great deal of education.

Resulting to obscenities and name calling has no place on this, nor any other forum, and is a sign of an emotional outbreak and immaturity.

Examine his [Ophiolite's]other posts and you'll definitely see the mood swings: sometimes extremely polite, then seconds later an outburst of agressive hostility.These are not mood swings. I treat thoughtful, considerate, sensible posters with politeness even deference. I attack aggressively displays of stupidity, willfull ignorance, intolerance, intrasigence, rudeness and bullying. You may wish to recall that I attacked Invert Nexus for condemning your resurrection of old threads. I stand by that attack and my justification for it.
InvertNexus has already pointed out that your citation of textbooks only addresses the KT event. I ask you again, please cite a textbook that relates the other major extinctions, primarily, to a bolide impact.
My previous request for this was clear, I think. Certainly InvertNexus understood it. Yet your response appears to regurgitate a stream of peripheral facts that have little or no bearing on the simple question. I am beginning to suspect Invert's view, that you are trying to appear erudite, may be correct.
Valich, you clearly have a good brain, you are quite widely read, you know how to use google. We can have some interesting conversations. But please try to be a little more thoughtful in what you post, or you will induce another mood swing!
And while you are thinking about that I'll ask yet again for a textbook that relates the other major extinctions, primarily, to a bolide impact. Pretty please.

I've received a lot of compliments from other members on other forums for providing web links and quotes. And yes I have been participating in forums for about six years now. Most of the other ones were medical forums so they involved folks with a great deal of education.

Insinuating that those that don't 'complimient' you have no education?
Pshaw.

Different forums have different mechanics. Some forums are dry. Some forums are gathering places of people who like to stroke each other and be stroked in return. Some forums are playgrounds for children and trolls.

This forum is... this forum.

All I can say is that from what I've seen, I stand by my viewpoint that you are trying to appear more knowledgeable than you are. I'm not the only one. Ophiolite mentioned that your enthusiasm outstripped your research or something similar.

The point being that I'm not getting on you about posting that textbook quote (although it didn't have anything to do with Ophiolite's objections to your original post about the 5 extinction events, 4 of which you claimed to be caused by meteoric impact. The KT event isn't disputed other than it might not be the sole cause of the extinction.) I'm getting onto you because this forum isn't about dry facts. I'm not saying that you should never post links and/or quotes. Just that we're more interested in what you know than what you are able to find on the net.

Resulting to obscenities and name calling has no place on this, nor any other forum, and is a sign of an emotional outbreak and immaturity.

You obviously have no clue what this forum is like then... Ha!
Anyway. I only resorted to name-calling because you resorted to grammar patrol. Grammar patrol is the occupation of douche-bags. (What's so obscene about douche bags anyway? Ever consider that the dinosaurs might have succumbed to vaginal infections? For lack of douche bag, the Cretacious was lost.... Muaha!)


Anyway. So. You're saying you're a medical doctor? Or did you just post in medical forums to associate with doctors?

Iridium deposits were also found in the late Devonian extinction (~350 million years ago). But meteors are not the only causes of the previous mass distinctions, nor are iridium deposits. Scientists look at the sudden stop in fossil evidence for the diversity of so many species, plate tectonics, sudden drops in global temperatures,sea level changes that at times covered the earth, carbon isotope changes that indicate organic productivity, abnormalities in quartz crystal structure that indicate "shock" events like that of a sudden meteor impact, lava flows from volcanic activities, and, as in the case of the late Permian extinction (250 mya - the largest extinction in earth's history) the sudden loss of accumulation of sedimentary carbon deposits that lasted for 6 million years. In other words, for 6 million years their was a sudden absence of organic matter decomposition that is compressed under pressure and temperature in deposits to form carbon. This is a clear indication of a massive extinction. During this extinction their is evidence of a sudden increase in the earth's temperature, probably caused by massive outbursts of lava eruptions through plate tectonic cracks, as is evidence from the huge lava flows around long plate tectonic adjacent areas.

See? You were called on the fact that you posted that bit about meteor impacts causing all the extinction events, and now you post this about how they're not. But, this is an about face from what you've said. You've done this several times too. I can understand you being wrong, but the way you respond when you're called on being incorrect is... evasive.

Did you or did you not claim that all but 1 of the 5 extinction events you posted earlier were caused by meteoric impacts?

(By the way, Iridium didn't cause the extinction, it was merely a means of proving meteoric impact... (vulcanism can also cause iridium deposits...))

Warning: Mood swing in progress. Most of the other ones were medical forums so they involved folks with a great deal of education.

Resulting to obscenities and name calling has no place on this, nor any other forum, and is a sign of an emotional outbreak and immaturity.
Ahem. Your first sentence above is a clear implication that the folks you are dealing with here do not have a great deal of education. Would you not put that in the category of name calling?

By the way, the mature way to deal with name calling is to ignore it and concentrate on the facts. I hope you will do so.

First being exceptionally polite. Then aggresively attackin someone for what you "perceive" as "stupidy, willfull ignorance (whatever that means?)," etc. is a mood swing.

I summarized all five extinctions - not just the KT - and in my last post I just gave you the consensus about the diverse scientific evidence for all of those five extinctions. If you research each one of those previous extinctions individually I'm sure you'll come up with more solid evidence, concrete facts, and the scientific research that has been done to show them.

Again - I guess I have to repeat - I am not trying to appear "erudite." This is a scientific forum and we are after the truth about the subject and use scientific facts. By posting brief cited quotations I am being very objective, giving no one any persuasion of what they want to think about my socalled "appearance," and am leaving the interpretation of that cited quotation up to the reader to decide and then discuss. But by resorting to name calling and swearing is a sign of ignorance too (lack of education) - and definitely a sign of immaturity.

I just gave you the names of two textbook's that do refer to a bolide impact. I do not have any other textbooks with me at home. I do, however, have quite a few geology books that I could look through to see what they say about the subject if you wish?

Warning: Mood swing in progress.
Ahem. Your first sentence above is a clear implication that the folks you are dealing with here do not have a great deal of education. Would you not put that in the category of name calling?

By the way, the mature way to deal with name calling is to ignore it and concentrate on the facts. I hope you will do so.

Some of the posts on this forum reveal a great deal of admirable inquisitions about the cause and result of the K-T extinctions, but no reference to the other even more massive ones. I am in no way implying "stupidity," if that's what you're trying to get at. I have a lack of education on the subject too! And an equal desire to learn more. But if I have something to contribute to those others who have a respectable sincere desire to know something, and I have an answer for it through what I have learned, then shouldn't I post it? So that we can then move on - progress - from there?

But by resorting to name calling and swearing is a sign of ignorance too (lack of education) - and definitely a sign of immaturity.

Non sequitur.
And a blatant one at that.

This is a scientific forum and we are after the truth about the subject and use scientific facts. By posting brief cited quotations I am being very objective, giving no one any persuasion of what they want to think about my socalled "appearance," and am leaving the interpretation of that cited quotation up to the reader to decide and then discuss.

Well. This is a discussion forum that centers around the topic of science... It's been said that we're more of a debate forum than most other forums based on science.

But. Consider your posting of 'cited quotations' and links. You don't see such quotes in scientific papers (not making up the entire paper anyhow.) The citations come after the paper so that the reader can go look them up himself if he cares to.

However, the thing is that I'm not getting on you about posting quotes and citations or whatever. More like that you do it so much and that they are so often not urbane to the conversation. Try injecting some of yourself into your posts.

Meh. Anyway. Post as you will. And so will I. Just trying to help (even if I'm an asshole about it. You'll become an asshole too if you stick around. Even Ophiolite is turning into an asshole... Muaha!!)


Anyway.
On the subject of mass extinctions and meteoric impacts, the general consensus is that only the KT event has strong evidence for such an occurrence. The rest are disputed and disputed widely and with much fervor.

I repeat. If your textbooks are teaching otherwise, then they're wrong. I suspect that they're not saying any such thing however.

Valich, in your summary of the five extinctions you made these points(The emphasis is mine.):
1) 65 million years ago: 76% of species disappeared from the meteor impact off the coast of the Yucatan Peninsula in Mexico.
2) about 206 million years ago: a large meteor crashed into Quebec, Canada wiping out 65% of the species on earth at the end of Triassic period.
3) about 250 million years ago: a large meteor crashed into Northwestern Australia, with a massive outflow of lava and the extinction of about 96% of the world's animal species.
4) 355 million years ago: two large meteorites hit Nevada and Western Australia possibly causing the extinction of 75% of the world's species. Scientists are still uncertain about the exact cause.
5) about 443 million years ago: massive glaciers formed causing sea levels to drop 50 meters and ocean temperatures to drop resulting in the extinction of 75% of all animal species.


I then stated “I am certainly very far from convinced that any of the earlier extinction events are related to impacts. You are being rather optimistic in suggesting that we have solid evidence to support these events.”

Your response: “this is what is being written down in many textbooks as fact and I haven't heard of any researchers going out there trying to disprove them.”

My request: “Please cite a single textbook in which the mass extinctions,other than the KT boundary event, you list in yesterday's post are attributed exclusively or primarily to bolide impact.”

Valich, I am still waiting. Do you not see what is wrong here. You provide a list that attributes four of five major extinction events to meteor impact. You say this information is to be found in many textbooks. Yet you have so far failed to name a single textbook which states this that does not relate to the KT event.
In short, I am stating that your list is wrong. I am asking you to cite evidence to support it. I have asked repeatedly. You have failed to do so. What should I make of this?

On a side issue, on at least one or two occasions in this thread you have repeated the evidence for mass extinctions as though we were disputing them. Nobody is debating that mass extinctions have occurred. I am debating whether there is sufficient evidence to tie any of them, apart from the KT event, to a bolide impact. Either you lack the education to understand the distinction or you are being deliberately obtuse. Both are correctable deficiencies. If there is a third explanation I would be happy to hear it.

Non sequitur.
And a blatant one at that.



Well. This is a discussion forum that centers around the topic of science... It's been said that we're more of a debate forum than most other forums based on science.

But. Consider your posting of 'cited quotations' and links. You don't see such quotes in scientific papers (not making up the entire paper anyhow.) The citations come after the paper so that the reader can go look them up himself if he cares to.

However, the thing is that I'm not getting on you about posting quotes and citations or whatever. More like that you do it so much and that they are so often not urbane to the conversation. Try injecting some of yourself into your posts.

Meh. Anyway. Post as you will. And so will I. Just trying to help (even if I'm an asshole about it. You'll become an asshole too if you stick around. Even Ophiolite is turning into an asshole... Muaha!!)


Anyway.
On the subject of mass extinctions and meteoric impacts, the general consensus is that only the KT event has strong evidence for such an occurrence. The rest are disputed and disputed widely and with much fervor.

I repeat. If your textbooks are teaching otherwise, then they're wrong. I suspect that they're not saying any such thing however.

Again, you're resorting to name calling, and in the process, whether you realize it or not, your making a donkey ass out of yourself by calling everybody else the same.

Further, these are not MY textbook, as you refer to them as "yours." These are textbooks used all over the world by millions of people.

And again - I guess I need to repeat myself - all of my first eight postings on this forum, except for the two above today - and these were asked for as references - included no quotations. They were all of MY own words.

We are not writing a book or an article here, so it would be inappropriate to post a quotation at the end, and how would you know when the end is anyways?

I just gave you the names of two textbook's that do refer to a bolide impact.
Sorry. Where? I can't find them. I am sure you have given them, but I can't see them. Would you be good enough to post them again please.

OK. Just found them.
from "Biology," by Raven, Peter H. and George B. Johnson, 6th edition
(International Edition), 2002, page 473.

William K. Purves, et. al.'s book "Life: The Science of Biology," 7th edition, 2006

You quote briefly from the first one a segment that refers to the KT impact event. I have clearly stipulated, repeatedly, that we accept that an impact was very probably implicated in the KT extinction. Would you please quote a segment that clearly states impacts were the cause of the other events.

You tell us the second source has useful charts. Please quote a passage that states impacts caused the earlier extinction events.

Again, you're resorting to name calling, and in the process, whether you realize it or not, your making a donkey ass out of yourself by calling everybody else the same.

Eh?
When? When I called myself an asshole? And when I said Ophiolite was becoming an asshole too?
It's called a sense of humor. Acquire one.
Although it's also the truth. I'm an asshole. I'll admit it.
And I've seen Ophiolite be an asshole here and there as well.
Nothing wrong with being an asshole.

(By the way. In case English isn't your primary language and you don't understand the nuance. Asshole refers to bluntness. (That's how I use it, anyway.) Your mention of 'donkey ass' would seem to relate more to foolishness or ignorance. Two completely different concepts.)

Further, these are not MY textbook, as you refer to them as "yours." These are textbooks used all over the world by millions of people.

More grammar patrol? Should I break out the 'douche bag' again?
They're 'your' text books in that you've read them. They are/were in your possession.
You're the one who is claiming that they exist.

If they claim that meteoric impacts are the cause of previous extinction events as you have claimed then they are wrong.
However. As I've said before, I don't think they say that. I think you're misinterpreting them. I think they mention meteoric impacts as possibilities but that you've taken them to be more factual than they actually are.

And again - I guess I need to repeat myself - all of my first eight postings on this forum, except for the two above today - and these were asked for as references - included no quotations. They were all of MY own words.

Yes. Yes. I know. I'm talking about your posting style in general. You do post in other threads than this one, you know. (They're called threads, not forums, by the way. Not trying to be grammar patrol here. Just clearing it up for you so that you know the right word. English is a second language for you? Perhaps much of this is about cultural differences. NOte also that in all my 'character studies' of you these are only impressions I've gathered from reading your words. I can't claim that they're fact or not. I'm only making comments on how you're coming across to me and (I suspect) to others.)

We are not writing a book or an article here, so it would be inappropriate to post a quotation at the end, and how would you know when the end is anyways?

Exactly. We're not writing a book or a scientific paper. Therefore citations are not absolutely necessary all the time. Sometimes they are asked for and can be posted. Sometimes the links say it better than you can so you post a link so that the interested can follow the link and read more than you're wishing to discuss in thread.

Look. This is complicated. Posting styles and all. All I can say is that your use of quotes seems... excessive. And that many of the quotes dredged up aren't even relevant and are, at times, used out of context by you.

Anyway. Look. I'm being an asshole. I'll admit. But, like I said before, even though you come across a bit as a faker, you're better than the idiots. That's why I'm trying to get the point across to you. However, I'm pretty much done with trying. You either understand or you don't and from now on you're on your own.

I do apologize for bringing this thread to such a personal issue anyway. But, it seemed pertinent when you turned on Ophiolite for having 'mood swings'. It seemed to me that you didn't like it when consistently called you on your errors. You seemed evasive.

Anyway. Enough. Post as you will.

Valich, in your summary of the five extinctions you made these points(The emphasis is mine.):
1) 65 million years ago: 76% of species disappeared from the meteor impact off the coast of the Yucatan Peninsula in Mexico.
2) about 206 million years ago: a large meteor crashed into Quebec, Canada wiping out 65% of the species on earth at the end of Triassic period.
3) about 250 million years ago: a large meteor crashed into Northwestern Australia, with a massive outflow of lava and the extinction of about 96% of the world's animal species.
4) 355 million years ago: two large meteorites hit Nevada and Western Australia possibly causing the extinction of 75% of the world's species. Scientists are still uncertain about the exact cause.
5) about 443 million years ago: massive glaciers formed causing sea levels to drop 50 meters and ocean temperatures to drop resulting in the extinction of 75% of all animal species.


I then stated “I am certainly very far from convinced that any of the earlier extinction events are related to impacts. You are being rather optimistic in suggesting that we have solid evidence to support these events.”

Your response: “this is what is being written down in many textbooks as fact and I haven't heard of any researchers going out there trying to disprove them.”

My request: “Please cite a single textbook in which the mass extinctions,other than the KT boundary event, you list in yesterday's post are attributed exclusively or primarily to bolide impact.”

Valich, I am still waiting. Do you not see what is wrong here. You provide a list that attributes four of five major extinction events to meteor impact. You say this information is to be found in many textbooks. Yet you have so far failed to name a single textbook which states this that does not relate to the KT event.
In short, I am stating that your list is wrong. I am asking you to cite evidence to support it. I have asked repeatedly. You have failed to do so. What should I make of this?

On a side issue, on at least one or two occasions in this thread you have repeated the evidence for mass extinctions as though we were disputing them. Nobody is debating that mass extinctions have occurred. I am debating whether there is sufficient evidence to tie any of them, apart from the KT event, to a bolide impact. Either you lack the education to understand the distinction or you are being deliberately obtuse. Both are correctable deficiencies. If there is a third explanation I would be happy to hear it.

Again, I just gave you the names of two textbooks above in my previous post today that states that the K-T event is attributed to the Yucatan meteor impact. There are more. This is exactly what you asked for. Do you want me to go to the Yucatan and bring back the Iridium? It's found in a layer of varying depths all around the entire world and that proves that a layer of ash was in the atmosphere that blocked out the sunlight all over the world, causing the earth to cool, the climate to change, and plants and animals to die. The meteor also caused massive tidal waves at heights, duration, and lengths unimaginable today. It also caused massive forest fires as can be obviouisly determined through the analysis of the heat generated by the size of the meteor, which can be determined by the size of the crater and carbon isotope dating. I also stated that:

"Iridium deposits were also found in the late Devonian extinction (~350 million years ago). But meteors are not the only causes of the previous mass distinctions." And I could search for the scientific articles that relay this factual information. They found iridium at the time of this extinction too: this is a fact. Enough so that the consensus is that it is attributed to a meteor impact. Just do a little research. If I post another quotation from a scientific research article, then I'm going to get condemned by Invert for doing that! For not using my own words like I'm doing right now.

Again, I just gave you the names of two textbooks above in my previous post today that states that the K-T event is attributed to the Yucatan meteor impact.

Sigh.

Would you please quote a segment that clearly states impacts were the cause of the other events.

You tell us the second source has useful charts. Please quote a passage that states impacts caused the earlier extinction events.

As I said, unfortunately I only have these two textbooks at home, but I have about twenty geology books that I could also look through as well if you'd like me to? Time permitting, though, as I have work to do too.

This is from the William Purves, et. al. biology book cited above called "Life: The Science of Biology," page 448:

"At least 30 meteorites between the size of baseballs and soccer balls hit Earth each year. Collisions with large meteorites are rare, but large meteorites have been responsible for several mass extinctions. Evidence for these collisions is found in the craters that resulted from the impact, dramatic disfigurations of rocks (microspherules and shocked quartz crystals), and within giant molecules that contain trapped helium and argon with isotopic ratios characteristic of meteorites, which are very different from the ratios found on earth. Also fern fossils are abundant in rocks that formed at the end of the Triassic and Cretaceous periods. Because ferns can more quickly colonize and survive in bare environments than most other plants, their abundance suggests that meteorite impacts scoured vast areas of the Earth's surface."

As for the Devonian extinction (~354 mya), Purves only states, "Continents collide at the end of this period. Asteriod probably collides with Earth....An extinction of about 75 percent of all marine species marked the end of the Devonian. Paleontologists are uncertain about the cause of this mass extinction, but two large meteorites that collided with Earth at that time, one in present day Nevada, and the other in Western Australia, may have been responsible."

Personally, I have no opinion about the cause of the late Devonian mass extinction, but Iridium deposits have been found that support the other two, and I have read this in scientific journal articles. Also, in general, these mass extinctions, as Purves states, are one of the main reasons why we "mark" the end of one geological historic "period" and begin the start of another, based on much more evidence than just meteorite impacts.

At last. Thank you. Its like pulling teeth. Those remarks are much more guarded than your statements in your shortlist of extinctions. "their abundance suggest", "may have been responsible". I am contending, as I have from the start, that impacts may be involved in these extinctions, but there is no clear cut evidence, nor any general agreement that this is the case.

You go on to note:
"Also, in general, these mass extinctions, as Purves states, are one of the main reasons why we "mark" the end of one geological historic "period" and begin the start of another, based on much more evidence than just meteorite impacts."
For the last time I know about the mass extinctions. I am not disputing the mass extinctions. I've collected fossils from horizons above and below the strata associated with mass extinctions. I am stating, I hope for the last time, that there is little convincing evidence to demonstrate the role of bolide impact in mass extinction events other than the KT event.

Invert_Nexus:
And I've seen Ophiolite be an asshole here and there as well.

Nonsense. Refer to the words beneath my name.

Well I did have to search for it and you guys are getting on my case so much about quoting material, ya know? My geology books aren't much help either as they deal mostly with plate tectonics, rocks, gems, you know - geology. Although one book did make reference to a meteor that exploded 10 km. above Siberia in 1908 that flattened a large forested area and set off massive fires in the surrounding area. Woosh!

Valich, but do you see what is at the root of what Invert Nexus and I have been objecting to. You stated, in your list of major extinctions, that bolide impact had a role in four of the five. Not that it might have a role - it did have a role. This was wrong. I pointed this out and instead of saying, right, I see your point. You kept arguing it, and producing irrelevant data. Now that is no problem for Invert and me, since we both know what current theory is saying, but the casual lurker is going to go away with a wholly inaccurate picture of current thinking.
Don't take these corrections negatively: I am seeking to educate you, me and any others who are reading this.
So, while we are at it, it probably wasn't a meteor that exploded over Siberia, but a comet. That is why in my posts I have been continually referring to bolide impact, since that covers both asteroids (large meteors) and comets.
Peace.

Well, there is a movie where you might learn something about impact, dig though the nationalgeographic films in the nearest DVD store, i bet you will find something.

Valich, but do you see what is at the root of what Invert Nexus and I have been objecting to. You stated, in your list of major extinctions, that bolide impact had a role in four of the five. Not that it might have a role - it did have a role. This was wrong. I pointed this out and instead of saying, right, I see your point. You kept arguing it, and producing irrelevant data. Now that is no problem for Invert and me, since we both know what current theory is saying, but the casual lurker is going to go away with a wholly inaccurate picture of current thinking.


This is what I wrote and part of it is paraphrased from Purves' biology book:

1) 65 million years ago: 76% of species disappeared from the meteor impact off the coast of the Yucatan Peninsula in Mexico.
2) about 206 million years ago: a large meteor crashed into Quebec, Canada wiping out 65% of the species on earth at the end of Triassic period.
3) about 250 million years ago: a large meteor crashed into Northwestern Australia, WITH a massive outflow of lava AND the extinction of about 96% of the world's animal species.
4) 355 million years ago: two large meteorites hit Nevada and Western Australia POSSIBLY causing the extinction of 75% of the world's species. Scientists are still uncertain about the exact cause.

I do believe beyond any reasonable doubt from everything that I have read, heard, and been taught that K-T was caused by a meteorite. To much evidence to say it wasn't.

I substantiated my 2nd statement by stating that we have found iridium deposits during the time of the extinction, and there was rapid recolonization of fern which usually occurs only over barren wasteland, as caused by a meteor impact.

I did not say in my 3rd statement that the extinctions was caused SOLELY by a meteor, but that during this extinction another meteor did strike, along with evidence of massive outpourings of lava.

In my 4th statement, I said "possibly" causing - we do not know.

I believe that we have sufficient proof that at least two out of the five mass extinctions were caused almost exclusively by meteors, and that is what I stated. I did not come right out and say that 4 out of the 5 extinctions were entirely caused by meteors, but meteors did strike Earth during the 3rd one as well.

And yes, anytime such a large meteor like that strikes Earth, it's going to "have a role" in extinctions. This is not "wrong." Even the meteor that hit Siberia in 1908 might have wiped out certain subpecies that are only native to that region, like certain subspecies of wolves or insects or plants.

Valich, it appears to me you are so wrapped up in posting that you don't properly read the responses. Why do I say that - well amongst many other examples you are still referring to the impact in Siberia as a meteor, when I have already explained to you that it was almost certainly a comet.
Read this very carefully: I am not discussing what you think. You are entitled to your opinion, right or wrong. I am stating that the current consensus on the matter of mass extinctions is 'undecided'. Yes, there is evidence for bolide impact being involved in several of the mass extinctions. Only in the case of the KT event is this widely accepted, and even here there are a number of authorities who vigorously dispute it.
The evidence you have cited re-iridium (which can also be derived from volcanic eruptions) and fern colonization (which only requires a wasteland, which might well be derived through climatic change) are suggestive, but nowhere near conclusive.

No, the current "scientific" concensus on the matter is that KT extinction was caused solely by the result of the meteor: the layman's consensus is what differs. The books refer to the Siberian meteor as a meteor and I am not in the position to change the wording which would be a misinterpretation of what is written: they know more than I do about it. By stating the facts as I read them, I am avoiding posting any "opinion" at all, but you are. You are of the "opinion" that the Siberian meteor was a comet. That's your "opinion." I'm not saying that it wasn't, but I'll stick to what I read so as to avoid any misinterpretations and confusions, and to avoid expressing my opinion, rather than change my wording just for the sake of conforming to your opinion.

I know what Iridium is but I've never heard of the element or the word "re-iridium." Are you now creating your own language too?

Valich - just exactly how are you determining that this is the current scientific consensus? There remain a significant number of geolgists who a) do not believe that the extinction was a rapid event, and/or b) believe it was brought about by the massive eruption of the Deccan traps.
Geol Rundsch. 1996 Jun;85(2):191-210. Related Articles, Links


Multiple factors in the origin of the Cretaceous/Tertiary boundary: the role of environmental stress and Deccan Trap volcanism.

Glasby GP, Kunzendorf H.

Department of Earth Sciences, University of Sheffield, England.

A review of the scenarios for the Cretaceous/ Tertiary (K/T) boundary event is presented and a coherent hypothesis for the origin of the event is formulated. Many scientists now accept that the event was caused by a meteorite impact at Chicxulub in the Yucatan Peninsula, Mexico. Our investigations show that the oceans were already stressed by the end of the Late Cretaceous as a result of the long-term drop in atmospheric CO2, the long-term drop in sea level and the frequent development of oceanic anoxia. Extinction of some marine species was already occurring several million years prior to the K/T boundary. The biota were therefore susceptible to change. The eruption of the Deccan Traps, which began at 66.2 Ma, coincides with the K/T boundary events. It erupted huge quantities of H2SO4, HCl, CO2, dust and soot into the atmosphere and led to a significant drop in sea level and marked changes in ocean temperature. The result was a major reduction in oceanic productivity and the creation of an almost dead ocean. The volcanism lasted almost 0.7 m.y. Extinction of biological species was graded and appeared to correlate with the main eruptive events. Elements such as Ir were incorporated into the volcanic ash, possibly on soot particles. This horizon accumulated under anoxic conditions in local depressions and became the marker horizon for the K/T boundary. An oxidation front penetrated this horizon leading to the redistribution of elements. The eruption of the Deccan Traps is the largest volcanic event since the Permian-Triassic event at 245 Ma. It followed a period of 36 m.y. in which the earth's magnetic field failed to reverse. Instabilities in the mantle are thought to be responsible for this eruption and therefore for the K/T event. We therefore believe that the K/T event can be explained in terms of the effects of the Deccan volcanism on an already stressed biosphere. The meteorite impact at Chicxulub took place after the onset of Deccan volcanism. It probably played a regional, rather than global, role in the K/T extinction

I am unable to be part of a layman's consensus on this matter.
It is not my opinion that the Siberian bolide was a comet, it is the considered opinion of those who have researched the matter.
Brown JC, Hughes DW, Tunguska's comet and non-thermal (14)C production in the atmosphere.
Nature. 1977 Aug 11;268(5620):512-4.


Either english is not your native language, in which case trying to correct it in another's writing is risky, or you are being deliberately obtuse.

re-iridium - with respect to iridium - the evidence you have cited with respect to iridium - the evidence you have cited re-iridium.

Pause and think for a moment. Is it just possible that I have been studying these matters for slightly longer than you? Is it possible that I might have a degree in this area? Is it remotely possible that I have continued studying these and related topics after graduating? Is there the merest glimmer of a chance that on some of these issues I might just know a tiny bit more than you? Is there any ephemeral likelihood that I have been trying to share that knowledge with you in these posts, by correcting errors I have seen you make? And if any of these highly implausible, doubtless fictional speculations were actually true, do you think - faced with your reactions to such gentle corrections - that I might just be about to lapse into one of those mood swings you seem think I am prone to?

According to the consensus amongst the "scientific" community, the 1908 Siberian bolide was a meteor, not a comet, but the discussion about just what exactly it was is still being debated. Examine the much higher percentage of scientists that refer to it as a meteor in the journal list kept by the International Meteor Association www.imo.net/bib/mtitun0.html

Comets normally consist of consists chiefly of ammonia, methane, carbon dioxide, and water, and wouldn't have produced such a large explosion at that altitude: but there were iron and nickel fragments found.

"Sekanina admits the question is still open. "I tell you quite frankly that
there is a lot of handwaving in this. There isn't any quantitative theory
available that would give you so many tons of material at such and such a
height above the Earth's surface." Nevertheless, he is quick to add, the old
comet-tail hypothesis is untenable. Even the dustiest tail would not
contribute enough material to cause the glows seen.

While the finest particles drifted westward from Tunguska, some of the
vaporized remains of the meteorite condensed into particles a fraction of a
millimeter in size. They rained onto the devastated terrain, and microscopic
spheres of metal and glass were painstakingly sifted from the soil by
expeditions during the late 1950s and early 1960s. Lest there be any doubt of
their extraterrestial nature, Soviet researchers soon found abnormal
concentrations of nickel in the samples, indicative of meteoritic origin."

www.totse.com/en/technology/space_astronomy_nasa/tungusk2.html

"In 1993 researchers Chris Chyba, Paul Thomas, and Kevin Zahnle studied the Siberian explosion and concluded it was of this type -- a stone meteorite that exploded in the atmosphere. This conclusion was supported when Russian researchers found tiny stoney particles embedded in the trees at the collision site, matching the composition of common stone meteorites. The original asteroid fragment may have been roughly 50-60 meters (50-60 yards) in diameter." www.psi.edu/projects/siberia/siberia.html

You really are a very argumentatively-prone opinionated person.

Valich - just exactly how are you determining that this is the current scientific consensus?....

Department of Earth Sciences, University of Sheffield, England.

"Many scientists now accept that the event was caused by a meteorite impact at Chicxulub in the Yucatan Peninsula, Mexico."

As stated above in your quotation from one source, they offer another hypothesis, and I am not in disagreement with this. But what I said is basically what they are also saying, i.e., "the general consensus among the "scientific" community is that the KT extinction was caused by the Yucatan meteor." And your citation above reconfirms that. Many natural phenomena, and these mass extinctions, have other "contributing" causes, and I am not in disagreement with that. But that is not what I said.

You constantly keep subjectively misinterpreting my objectively cited quotations and comments.

You really are a very argumentatively-prone opinionated person.Then I'll leave you to stew in your own ignorance then. Gooday to you.

You guys condemn me for posting quotes, wasting your's and everybody else's time with two days of senseless mudswinging, and now you call me ignorant. Had you posted or paraphrased or given some indication of the other reasons why the meteor should not be considered as the "consensus" explanation among scientists, as it is right now, then we would have been having a productive and progressive discussion.

The article you posted, "Multiple factors in the origin of the Cretaceous/Tertiary boundary: the role of environmental stress and Deccan Trap volcanism." is very interesting and now gives me something more to think about - and I will.

Thanks for posting it!

Valich,

I wasn't exactly getting on your case for using quotes. It was more the manner in which you were using them. As you see, we all use them from time to time. It just seemed that your use of them was not only excessive, but also... tangential.

The main thing that I was getting on you about was a certain sense of evasiveness that I'd gathered from reading you. Consider that this whole thing was about trying to get you to realize that your statement on meteoric impact being the cause of the extinction in most of those events.

Now. Appeal to authority is a logical fallacy, but Ophiolite is in his element here. I'm not saying that he's always right or that he's some kind of font of truth in this field, but he is right this time (that is, I agree with him.) You seem to fail to realize the tentative nature of the bolide theory for extinction events. Only the KT event has any kind of surety in this. And even it is disputed (quite strongly in some circles.)

There is no 'truth' in this. Not even close. You seem to blithely accept bolide impact as the cause when it is in only conjecture and can only ever be conjecture. Even with the conjectural basis of the theory in hand, one must realize that only the KT event has any kind of solid evidence. The evidence for the rest is lacking in the extreme.

One problem with the earlier events is that, while certain craters have been hypothesized to have been made at roughly the same time as the extinction event, the correlation is weak for several reasons.

One reason is that the time of the various impacts are only roughly synchronous with the extinction events. Some happen before. Some happen after. There can be no certainty as to dates. They only roughly match.

Another reason is that the extinction events themselves are not so coherent as they might appear in a text book. The period of time that the various events spanned are debated strongly. Some seem reasonably quick but most seem to have stretched over a vast span of time. And several are even broken down into sub-extinction events.

A direct cause for each event is not known.
There is no 'general consensus'. The only one that comes close to a 'general consensus' is the KT event and even that is still debated.

Do you see what I'm saying? I feel I'm repeating myself here.

The key point is that the tentative nature of these theories must be stressed when they are spoken of. If they are not stressed then we have a case just as we are dealing with here. You have taken them to be far more certain than they are.

Now. You can go ahead and think that we're just being opinionated assholes on this, but you'll find the same thing everywhere you go. These are hotly disputed topics. In all circles. There is no consensus.


As to Tunguska. Well. I've seen no scientific literature of this specifically. Only popular treatment of it. But, from what I know the comet theory is the leading theory over the meteor theory. The chief reason being absence of a crater and meteor remnant. I've seen documentaries showing how they drained the swamp and went through the mud with a fine tooth comb looking for evidence and found little to support a meteor theory.

Now. Evidence can often be interpreted in multiple ways. And in this light you'll likely be able to find papers saying all sorts of things. In fact, this is exactly the sort of thing that comes from picking your sources carefully. If you are discriminating enough in your resource search, then you can present an argument that seems strong but is biased.

I have no direct knowledge on the subject and am unable to say whether it was a meteor or comet. However, from everything I've read and heard, I thought the comet theory was in the lead. And the reasons given made sense to me.

However, it must be borne in mind that it took half a century before it was even understood what happened at Tunguska. It wasn't until after the atomic bomb and the understanding of the effects of mid-air detonation that the enigmatic butterfly shape of the blast zone was understood.

There is always more to be learned in any given field.
And the fact that even such a recent event as Tunguska is still debated shows how much more debate must be going on in topics that stretch back the eons to the extinction events.

Science is not about truth. It's about problem-solving. Theories come. Theories go. The crucial thing to keep in mind is that scientific theories solve problems. (And, in themselves, present us with more problems to solve....)

Have you read Popper, by any chance?

Does anyone know about how big dinosaur penises are?

I've seen documentaries showing how they drained the swamp and went through the mud with a fine tooth comb looking for evidence and found little to support a meteor theory.....

There is always more to be learned in any given field.
And the fact that even such a recent event as Tunguska is still debated shows how much more debate must be going on in topics that stretch back the eons to the extinction events.

Science is not about truth. It's about problem-solving. Theories come. Theories go. The crucial thing to keep in mind is that scientific theories solve problems. (And, in themselves, present us with more problems to solve....)

Have you read Popper, by any chance?

You're right. You're repeating yourself a bit.

I read some of Popper many many years ago but doubt I could recall any specifics.

The problem with the meteor debate on this thread is that you guys never gave an opposing view to debate to begin with! Except if you want me to consider Jaxom's long proclamation on the first page that contained an endless list of numerous dubitable scenarios? As soon as I started quoting a source saying the meteor caused the extinctions, you two grabbed switchblades and axes and started hacking me to death without ever telling me why! You never presented any opposing views to counter it! All I kept hearing was: "Give me the proof," "Please cite a single source," "What does that have to do with the price of bread?," "You're disingenuous," "You're an ignorant asshole," etc. First you guys get on my case about quoting sources, then I'm being asked for "a single source," now, finally, both of you are quoting sources to provide and substantiate facts to form a basis for a forum to discuss and debate.

Only after Ophiolite quoted the article above with a differing explanation did I have any idea what you guys were talking about.

Does anyone know about how big dinosaur penises are?
You might get an approximate idea by comparing your's to a horse?

So quite small then.

Ha ha. I said a horse, not a pony!

" 2) about 206 million years ago: a large meteor crashed into Quebec, Canada wiping out 65% of the species on earth at the end of Triassic period."

...See, as I said, extinction level events are Canada's fault.
This was at the end of the Triassic Period (early dinosaurs); however, dinosaurs quickly diversified even more during the Jurassic, and did not become extinct until the end of the Cretaceous or early Tertiary.

REPLY CONCERNING:
I've seen documentaries showing how they drained the swamp and went through the mud with a fine tooth comb looking for evidence and found little to support a meteor theory.....
The massive thick layer of ash that is found in a stratified geographic layer throught the entire world corresponds precisely to that particular time period. The thickness and pervasiveness of this thick ash layer is living proof that during that exact period of time when dinosaurs became extinct, the entire earth's atmosphere was blanketed from the sun' rays for months, causing a dramatic decrease in temperature and destroying massive plant life that relies on the sun for photosynthesis. This plant life is the source of food and energy for all herbivores. This is most probably not the only cause of the mass extinction, but beyond a doubt, it had to be a major contributary cause. Thus is the consensus of the scientific/biological/evolutionist community.

Refer to the above postings. There were two, and posibly even three, mass extinctions involving dinosaurs, so we're not talking about a spontaneous event or a precise mount in history, i.e., an exact moment in history when ALL dinosaurs became extinct.

Sounds reasonable to me. Can I ask you what your source was that explains the stages? You're bound to get some opposition feedback, and I hope you stand your ground in answering any, but I'd like to read where you got this from. Thanks.

Think comets.... not meteors...

meteors do very little damage.... at least not world wide, unless they are really huge... and then the damage is earth shattering..

Comets on the other hand can envelope the whole of a planet with the effects of its decompositional products.

The theorem is based centrally on the concept of the true Angel of Death being the Hypercane as the source of the dust in the atmosphere, the frozen water lillies, and from my own experience with frost bite amongst others.
By exposing that your theorem is based on the socalled "true Angel of Death being the the Hypercane," you basicalling telling us that you are a psycopath!

Think comets.... not meteors...

meteors do very little damage.... at least not world wide, unless they are really huge... and then the damage is earth shattering..

Comets on the other hand can envelope the whole of a planet with the effects of its decompositional products.
That's not true at all. Comets usually burn up during entrance to the Earth's atmosphere. They are a lot smaller. Their composition doesn't include iron and nickle. And they disintegrate without having any effect on Earth. The Yucatan Penisula Meteor is considered to have been a meteor.

>> And they disintegrate without having any effect on Earth.

LOL

well we disagree.
Meteors have a local effect, comets can have a global effect. Comets are much more dangerous.

Well yes. That is how I see it - in a sense. I am not an astronomer, but the forum is about "Dinosaur Extinction." Meteors that hit earth have a much more catastrophic effect on the totally of Earth's environment than do the thousands of comets that rain down upon the Earth's atmosphere before they are able to effect it in anyway. Meteors have a "local" Earth effect, but as far as I know, comets do not? What are you trying to get at?

valich: Humble self is in state of dire confusion but is hoping imminent valich person can give illumination. Humble self has read in many astronomy texts that Earth enjoys great number of METEOR strikes every, with greatest portion burning in air and so not striking ground. Humble self has not read of any COMET strike upon Earth in recorded history.

Imminent valich person is invited to explain his greater knowledge in contradiction to established and published astronomical meteor and comet literature so that all may benefit from superior wisdom and not remain mired in mental swamp of conventional astronomy mistruths. :cool:

valich: Humble self is in state of dire confusion but is hoping imminent valich person can give illumination. Humble self has read in many astronomy texts that Earth enjoys great number of METEOR strikes every, with greatest portion burning in air and so not striking ground. Humble self has not read of any COMET strike upon Earth in recorded history.

Imminent valich person is invited to explain his greater knowledge in contradiction to established and published astronomical meteor and comet literature so that all may benefit from superior wisdom and not remain mired in mental swamp of conventional astronomy mistruths. :cool:
Read the facts that paleontologists and geologist have spent there life on. Your childish incoherent poetry belongs on a "how to raise a child" forum: not on Sciforum.

According to celestial being valich?

We are still waiting for master of wisdom valich to provide proof of meteor strike versus comet strike truth.

Anyone interested in verifying that exalted being valich is truthful in his statements claiming that many comets strike Earth every day and that few meteors strike Earth every day is invited to make a Google or Yahoo search of "meteor" and "comet" and see for themself where the facts lie. Lay? :cool:

Welcome CANGAS to the "Who's this ****** Vallich Society". Membership is open to all and is rapidly growing.

By the way the Siberian strike of 1908 was probably a comet.

The thing is Vallich doesn't quite grasp the difference between a meteor and an asteroid. A large lump of rock or nickel iron ten kilometres across is very definitely an asteroid. Meteors, as you point out, rain down all the time. If they don't burn up they get slowed to pretty much terminal velocity and do very little damage.

Will you consider asking the honourable Vallich these questions. "You say my poetry is childish and incomprehensible. Tell me oh wise one, if it is truly incomprehensible, then how can you discern that it is childish. To recognise its childishness would require that you first understand it at least in part. Please resolve this paradox for those of us who have intellects limited by a love of facts, rather than a love of self."

It is the only sequence which would fit the facts that would otherwise seem in contradiction, for example...
...why so few perished locked-in-combat
...why mid-latitude dinosaurs died quicker and worse than tropical ones
...why dinosaurs in the form of birds survived
...why the extinction was total
...why computer models show that the earth temperature was back to normal in 6 weeks or so
...how the nuclear winter could have occured.
The theorem is based centrally on the concept of the true Angel of Death being the Hypercane as the source of the dust in the atmosphere, the frozen water lillies, and from my own experience with frost bite amongst others.
I don't disagree with your above scenario, and as you can see, even another person refers to the "6-week nuclear winter," but what is the "true Angel of Death being the Hypercane"? Is this some sort of spiritual or religous attribute that you are adding to this scientific biology forum? I've never heard of this???

1. If you consider Cynodonts to be mammals then mammals arose before the dinosaurs.
2. Many dinosaurs were warm blooded.

Yes, Mammals evolved from Therapsida evolved from Synapsida which existed during the Triassic. Dinosaurs evolved from Diapsida.

When Spielberg's "Jurassic Park" came out I did hear about some speculation the some dinosaurs may have been warm-blooded but I haven't read any scientific literature on this. Do you have any journal citations? How would we know?

I will look through some old notes for citations. Their are several separate lines of argument. These are the ones I recall.
1) Phsyiological: extrapolating life styles from a variety of clues and comparison with modern predators, makes it highly probable that some were warm blooded.
2) The internal structure of the bones is consistent with a warm blooded status.
3) Increasing evidence for feathers on some dinosaurs is consistent with a trend to preserve heat.
There were, I think on more than one occasion, good review articles of the concept in Scientific American.

a good percentage in my opinion was not wiped out, dinosaurs merely evolved into the creatures you see before you today, i think all of the volocor raptor (pardon my spelling) type creatures evolved into birds, many birds resemble dinosaurs in amazingly accurate ways. even the skin around there talons indicates previously in evolution that this creature was reptilion like due tot he tough snake/reptile like feet.

a good percentage in my opinion was not wiped out, dinosaurs merely evolved into the creatures you see before you today, i think all of the volocor raptor (pardon my spelling) type creatures evolved into birds, many birds resemble dinosaurs in amazingly accurate ways. even the skin around there talons indicates previously in evolution that this creature was reptilion like due tot he tough snake/reptile like feet.
All modern day birds (Aves or Avians) and also indirectly crocodiles and the like (the taxa Crocodylomorpha) are descendents from dinosaurs. All other descendents of dinosaurs went extinct.

1) Phsyiological: extrapolating life styles from a variety of clues and comparison with modern predators, makes it highly probable that some were warm blooded.
2) The internal structure of the bones is consistent with a warm blooded status.
3) Increasing evidence for feathers on some dinosaurs is consistent with a trend to preserve heat.
That's an excelllent assumption. I don't think point 1 would be a clue because many birds and mammals are not predators, but 2 and 3 certainly are! It has been proposed that endothermic animals may require a heart with seperated cardiac chambers. Only birds and mammals have a four chambered heart that evolved from the two chambers (atrium and ventricle). If these bird-like dinosaurs had already evolved feathers and were not warm-blooded, they certainly must have at least been in that transition stage. If paleontologists have found any fossil evidence of a dinosaur with a four chambered heart, or at least one with anatomical seperations of the two chambers, that would in my opinion be pretty darn good conclusive evidence.

Only birds and mammals have a four chambered heart that evolved from the two chambers (atrium and ventricle). If these bird-like dinosaurs had already evolved feathers and were not warm-blooded, they certainly must have at least been in that transition stage. If paleontologists have found any fossil evidence of a dinosaur with a four chambered heart, or at least one with anatomical seperations of the two chambers, that would in my opinion be pretty darn good conclusive evidence.

Some hearts are made out of stone, but a dinosaur's heart apparently is made out of flesh. [insert sarcasm] tissue fossilizes very easily [end sarcasm].

Claims been made, claims been refuted (http://www.sciencemag.org/cgi/content/full/291/5505/783a)

[insert sarcasm] You know what real convincing evidence would be? If they would find a living dinosaur in the jungle of Borneo! [end sarcasm]

That's an excelllent assumption. I don't think point 1 would be a clue because many birds and mammals are not predators.

Bob Bakker published some work around 20 years ago, looking at the predator-prey ratios in different ecosystems. (Many dinosaurs weren't predators either.) In modern ecosystems, where the top predator is endothermic then you have around 1 predator for every 20 prey. Anything much less & the system can't supply the predator's energy demands. If the top predator is an ectotherm, eg a crocodile, then it's closer to 1 predator to 5 prey animals. The dinosaurian systems that Bakker looked at had predator-prey ratios similar to those for a modern endotherm-dominated system.

Some hearts are made out of stone, but a dinosaur's heart apparently is made out of flesh. [insert sarcasm] tissue fossilizes very easily [end sarcasm].

Claims been made, claims been refuted (http://www.sciencemag.org/cgi/content/full/291/5505/783a)

[insert sarcasm] You know what real convincing evidence would be? If they would find a living dinosaur in the jungle of Borneo! [end sarcasm]
Some mammals have been completely been preserved intact through freezing of swamps and marshes, as in recent discoveries of whole finds of mammoths. However, I was just informed by one of my colleagues that I must be wrong about four-chambered hearts necessitating warm blood because Crocodilia (Crocydlidae) also have four-chambered hearts. Ophiolite's three assumptions thus have no support for the theory of warm-bloodness.

However, I was just informed by one of my colleagues that I must be wrong about four-chambered hearts necessitating warm blood because Crocodilia (Crocydlidae) also have four-chambered hearts. Ophiolite's three assumptions thus have no support for the theory of warm-bloodness.

Hmm.
Interesting.
So. Ophiolite puts together a list of three items by which dinosaurs can be examined in order to put forth arguments on whether they might be warm-blooded or not and you respond to him by talking about four-chambered hearts. Then you go on to say that crocodiles have four-chambered hearts and thus seem to think that you've somehow disproved any of his list of three items?

Why do you think this?

You might be interested to know that the bone structure of dinosaurs is more similar to warm-blooded growth patterns than cold-blooded. I forget the exact reference and am not in the mood to go digging through my back copies of Science, but it's the one a few months back about soft tissue found in a T-Rex bone. I have little doubts there are other studies as well that point to warm-blooded growth patterns. The paradigm of cold-blooded dinosaurs is rapidly going the way of the... dinosaurs.

(Heh. I'm still getting a chuckle out of your interesting style of debate. Introducing 4-chambered hearts and then disproving yourself and thinking that it has any relevance to anyone's posts but yours. You really are a trip, dude. I still think you do this shit on purpose. I wonder who you really are? You're not new here, are you? Xev? Wanderer? Dr. Lou? Whoever you are, you certainly have a unique style.)

Hmm.
Interesting.
So. Ophiolite puts together a list of three items by which dinosaurs can be examined in order to put forth arguments on whether they might be warm-blooded or not and you respond to him by talking about four-chambered hearts. Then you go on to say that crocodiles have four-chambered hearts and thus seem to think that you've somehow disproved any of his list of three items?

Why do you think this?

You might be interested to know that the bone structure of dinosaurs is more similar to warm-blooded growth patterns than cold-blooded. I forget the exact reference and am not in the mood to go digging through my back copies of Science, but it's the one a few months back about soft tissue found in a T-Rex bone. I have little doubts there are other studies as well that point to warm-blooded growth patterns. The paradigm of cold-blooded dinosaurs is rapidly going the way of the... dinosaurs.

(Heh. I'm still getting a chuckle out of your interesting style of debate. Introducing 4-chambered hearts and then disproving yourself and thinking that it has any relevance to anyone's posts but yours. You really are a trip, dude. I still think you do this shit on purpose. I wonder who you really are? You're not new here, are you? Xev? Wanderer? Dr. Lou? Whoever you are, you certainly have a unique style.)
As usual, you're just only trying to start an obnoxious, belligerent, unproductive argument. Ophiolite posted:
1) Phsyiological: extrapolating life styles from a variety of clues and comparison with modern predators, makes it highly probable that some were warm blooded.
2) The internal structure of the bones is consistent with a warm blooded status.
3) Increasing evidence for feathers on some dinosaurs is consistent with a trend to preserve heat.
There were, I think on more than one occasion, good review articles of the concept in Scientific American.We can certainly exclude point 1 outright (see above). As I said above, points 2 and 3 deserve good merit, however they do not prove anything decisive. As I asked him: cite your sources. What is the further proof? Or was this just a speculation to transition? I don't know? Are you citing any facts? Or just wasting time posting further unnecessary wasteful bull? What did your post in any way contribute to the advancement to academic knowledge? Nothing but waste of time. If you've got factual knowledge to post, that you can cite, substantiate or prove, then please post it!

As usual, you're just only trying to start an obnoxious, belligerent, unproductive argument.

As usual, you're being a trollish dolt who has no answer to any rebuttals but "you're an obnoxious, belligerent who doesn't respect knowledge like I do! You're a bad person! You hate me and have an agenda against me!"

You suck.

e can certainly exclude point 1 outright (see above).

Your exclusion of point one because of the idea that there are many dinosaurs that weren't predators is asinine. There are lots of mammals that aren't predators too, Einstein. If you think that you can't compare lifestyles of dinosaurs with the lifestyles of extant mammals... then what was all that talk about the albatross and the pterodactyl?... Pause. You... still don't understand what that paper was all about, do you? Sigh. You're a very ridiculously... ridiculous person.

As I said above, points 2 and 3 deserve good merit, however they do not prove anything decisive.

Yeah? So? Then why did you feel you disproved his three points when you brought up the 4-chambered heart?
C'mon, Valich. Is it too much to expect you to actually follow a conversation? You do realize that you reply to things people have said and are expected to actually, you know, back those things up somehow rather than simply diverting everytime you're called on your idiocy.

You stated that crocodiles having 4-chambered hearts invalidates Ophiolite's three points. This is what you said. Why do you feel that crocodile hearts have anything to do with his three points?

As I asked him: cite your sources. What is the further proof? Or was this just a speculation to transition? I don't know?

"State your sources! State your sources!!!"
Christ, man. Grow the fuck up. His points are plainly obvious and need no 'sources'. You do realize that one's own brain can be the source of thoughts, don't you? And you do realize that your brain can digest these thoughts and derive the possibility of truth or falsehood from them?

Here's another nursery rhyme for you, little boy. "I'm bringing home a baby bumblebee... Won't my momma be so proud of me? I'm bringing home a baby bumble bee..."

Barney loves you, Valich.

Are you citing any facts? Or just wasting time posting further unnecessary wasteful bull? What did your post in any way contribute to the advancement to academic knowledge? Nothing but waste of time. If you've got factual knowledge to post, that you can cite, substantiate or prove, then please post it!

Hey. Dipshit. T-rex. Bone structure. Warm-blooded vs. cold-blooded bone formation. Soft tissue found in fossils. Science magazine. I already stated that I don't have the time to go digging for the exact reference, or any of the other many others that follow a similar vein (ha! You're too stupid to even realize the pun I just made...) but they do exist, I assure you.

"How does your post further academic knowledge? You're not furthering the cause of SCIENCE the way that I am!! You're just a stupid, belligerent person who doesn't respect SCIENCE and doesn't understand my huge brain, you big meany!!"

Seriously, dude. You're such a douche bag. You can only be doing this shit on purpos