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Science

Dinosaurs Not Killed By Blast -- But By Acid Rain? 20

Posted by Hemos from the flip-flop-flip-flop dept.
JCMay writes "FoxNews is reporting that it wasn't just the impact of a ten-mile wide asateroid in Mexico that killed off the dinosaurs, but rather the chemicals kicked up-- mostly carbon dioxide and many sulfur-bearing compounds."
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Dinosaurs Not Killed By Blast -- But By Acid Rain? More

Dinosaurs Not Killed By Blast -- But By Acid Rain?

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  • Let's not forget alien autopsy. Although I think that most people already have.

    ... I think you all trust The Simpsons. They take Fox with a grain of salt; we should follow suit.
  • We all know that dinosaurs were killed largely by second-hand smoke. Just imagine the size of the cigarettes it would take to give a brachiosaurus a nicotine buzz...

  • Re:problem with this theory (Score:3)

    by bcrowell ( 177657 ) on Tuesday December 19, 2000 @07:35PM (#547782) Homepage
    A standard argument against the giant impact theory of the extinction was always that certain critters, e.g. dinosaurs, went extinct, while others, e.g. reptiles, didn't. Same thing with plankton -- some bought the farm, but other very similar species survived.

    The evidence is very strong that there was a giant impact, but it doesn't completely explain the pattern of extinctions. However, there was an interesting recent case where someone studied the area around a volcano that had erupted (was it Mt. St. Helens??) and found that it was surprisingly random what plants got the first toeholds in the newly sterilized area.

    People who disbelieve the giant impact explanation say it's straightforward: a crocodilian species and a dinosaur species might have been competing in the same ecological niche. One won, the other lost.

    If this theory were true, wouldn't that mean that many other organisms other than the dinosaurs were killed? I mean, the article talks about highly toxis "globs" of sulfuric acid throughout the atmosphere. I strongly doubt anything more complicated that certain prokaryotes could survive that!
    I guess it's all a matter of how concentrated the toxins are and how robust different parts of the ecology are. Kill off all the green plants, and the whole animal food chain gets pretty much destroyed. Then new plants grow from seed.

  • What really killed the dinosaurs was a bunch of little lizard dudes with ray guns. They used to hunt them you see.
    Once they'd killed off all the dinosaurs they ran around zapping each other, until there were none left.

    Seriously.

    Gev.

  • If this theory were true, wouldn't that mean that many other organisms other than the dinosaurs were killed? I mean, the article talks about highly toxis "globs" of sulfuric acid throughout the atmosphere. I strongly doubt anything more complicated that certain prokaryotes could survive that!

    -mdek.net [mdek.net]
  • wait....... wouldent some organizms have enough sense to go live in a cave for awhile? Wouldent that offer limited protection?
  • This shows how tough they were, I doubt that I could watch Requiem for a Dream over and over......
  • ort.

    Are they saying that the only damage done by the dust and tiny debris was by pelting the animals? It seems they forgot about about the similarities to a nuclear winter.(Blocking sunlight, temp changes, etc. ) Yes, the chemical composition of the percipitation was probably altered, (How's that for a sentence full of $25 dollar words) but I don't think that was the major cause. I believe starvation was.
  • Could someone post a summary of the [competing] extinction theories?
  • Great theory, they were hit on the back of the head by flying rocks. The absolute precision of a totally random event. Geez, where do you get this stuff? -- Racism is one of the few jokes the Devil laughs at, and the only one he bothers to retell. Think of it, the cosmic irony of "They are lesser men then I because of their skin", and its ugly brother "They will treat me as less of a man because of the color of my skin" coming from the mouths of creatures made in the image of God. --
  • Well according to /. we've got the following theories:

    Article: acid rain
    Second hand smoke,
    ray guns and a bad attitude,
    bad dino indigestion,
    Alien massacre for their breeding program,
    and mine:
    They all stayed up late one night, watched The Thin Red Line and Requiem for a Dream over and over until they decided there was no reason to live, then promptly crawled underneath the nearest rock, and died.

    Ah its good to see /. is at the forefront of modern day science.

    rosie_bhjp
  • Some have also attributed the asteroid impact, if it happened, to introducing a new microscopic life form, like a virus or bacteria.

    From there, it's pretty easy to extrapolate: Something shades of "Andromeda Strain" or "The Stand" happened, and the ones who didn't have the natural immunity to the virus died. Not a superflu virus, just a normal one like AIDS that slowly killed.
    -----------------------
  • I've wondered if the big mean dinos like T Rex didn't starve by eating everything else. Most "man eaters" like tigers, crocks and sharks only eat in very select situations. Many agressive sharks will not eat healty fish but can consume massive amounts of injured fish. Most reptiles are quite selective of how they feed. I wonder if T Rex didn't have that, would it simply eat until it had removed all food sources? It was large enough that it could go weeks or months without food if it could act like a modern crock.
  • Nice recap of Science According to Slashdot.
  • For an excellent presentation of the "Deccan Traps" volcanism theory, try Courtillot's Evolutionary Catastrophes [dannyreviews.com].

    Danny.

  • Large animals need a LOT more food than small animals to survive. Most of the large animal species thrived in conditions of plentiful food, then went extinct when food became scarce. Any credible explanation of the extinction of dinosaurs must explain why larger animals died out whilst smaller ones survived; shortage of food caused by climactic change and possible poisoning of PLANTS by acid rain fits this criterion. The suggestion that an excess of carbon dioxide killed the dinosaurs is absurd; this would have resulted in MORE food, since plants thrive on carbon dioxide (unless the carbon dioxide caused global warming, which in turn caused desertification of much of the planet. Also, the extinction occured over a much larger time period of time than poisons would have remained in the atmosphere.

    Conclusion: This report is 99 and 44/100ths percent pure bull!

  • Did many people every actually believe it was the debris that killed many species?
    Although the size of the impact was very large, it would have to be many times larger for
    pieces of debris to hit enough life forms to inhibit their survival. Even fires caused by the
    impact would not directly kill them. Real scientists never really suspected this was the
    cause of this massive extinction, as it is really quite ridiculous. Instead most believed that it
    resulted from a sudden climate change, possibly caused by the resulting fires and dust
    blocking the sun combined with cyclical changes do to the earth's changing orbit and
    precession (angles).
  • The FOX reporting here looks garbled - they say something about comparing it to the large Sudbury impact, and that Sudbury was formed by a high-velocity comet while the Chicxulub (sp?) crater was formed by an asteroid - however doesn't Sudbury have a huge quantity of asteroidal metals (it provides most of the world's nickel supply, for example)? I didn't think that's what comets were supposed to be made of... So did they just get these switched and it was actually a comet that killed the dinosaurs? Does anybody have any more links/references on this finding?
  • /. theories aside, here's what I remember from my paleo classes...

    • Asteroid impact... this has been a favorite since Alvarez found the Iridium layer. The theory goes that ~65 million years ago, a massive asteroid impacted, somewhere around the Carribean. From there, the theory fragments; some go for nuclear winter, others go for acid rain and worldwide forest-fires. There's lots of evidence that there was in fact an asteroid impact, but there's also a lot of evidence that the results were nowhere near as bad as everyone claims. Soil samples don't suggest acid rain, nor ice age. Most importantly, the fossil record doesn't support this. What everyone forgets is that the dinosaurs didn't die in a week. Think about it, if an asteroid did all the work, you'd expect there to be a colossal slaughter, but we don't see that in the record...

    • Plants became poisonous and killed off dinosaurs... too many issues with this theory.

    • Mass migration moved diseases around which killed the dinos. This wouldn't be enough to remove them all, but it's got some good points: it would target large mobile critters more, and a disease would be more likely to affect similar animals (like dinos) but exclude others. Still, there are issues here...

    • Deccan Traps. When India slammed into the Asian continent, it pushed up the Himalayas, and created lava flows that covered millions of square acres. The amount of ejecta from the eruptions could have created a nuclear winter on its own (think St. Helens but millions of times worse).

    No one really knows what killed off the dinosaurs, but to say that the asteroid did it itself is ridiculous. It's simply not supported. The dinosaurs were dying off for millions of years; The Cretaceous period started with really high species (dinosaur) diversity... by the end, there were pretty much two species left: T-Rex and Triceratops... the duckbills, the other Ceratopsians, etc, were almost extinct already.

    Most likely it was a combination of many of these things... Diseases start to ravage certain lineages, others can't compete with new types of plants, and slowly die off. The climate changes due to massive volcanic eruptions, and this adds more challenges to various species. After a few million years of this, dinosaurs as a class are hurting: they have little species diversity left, and are unlikely to recover. An asteroid impact puts the final touch on it...

    For more reading check the following links:

    A Cowen Essay posted on UCMP [berkeley.edu]
    Summaries from UCMP [berkeley.edu]
    Also, see The Dinosaur Heresies by Robert Bakker... His ideas are interesting and opposite of much of UCMP's thoughts. But he's definitely worth reading; I recommend this to anyone interested in dinos...

  • Come on, from the network that brought us, "When good pets go bad?" How can you report this crap? I can't believe of all the submissions in the bin this was the one that got posted.

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