K-T Extinction Event

Discussion in 'Earth Science' started by Trippy, Mar 5, 2010.

  1. Trippy ALEA IACTA EST Staff Member

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    Continued...
     
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  3. Repo Man Valued Senior Member

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    Probably thirteen years or so ago, Nova had a program about the Chicxulub impact. The next day at work, I made the mistake of trying to get a conversation going with a co-worker about it. "You believe that shit?" was his reply. I didn't make that mistake again.

    I guess continuing research has only continued to strengthen the asteroid hypothesis.

    Cormac McCarthy's novel The Road is set in a bleak future where some catastrophe has taken place. From what little is said about it, and the description of the landscape, I think the event that caused it was likely an asteroid impact. It's a very pessimistic look at how things might go for the survivors of the initial impact. Both the book and film are excellent, but you might feel compelled to take anti depressants afterward.

    Trailer for The Road.
     
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  5. iceaura Valued Senior Member

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    It hadn't occurred to me, before, that the diameter of the asteroid itself would make a hole in the lower atmosphere.
     
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  7. madanthonywayne Morning in America Registered Senior Member

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    For a more upbeat end of the world story, try Lucifer's Hammer:

    Please Register or Log in to view the hidden image!


    Although civilization is destroyed and we are reduced to eating rats (and each other), it actually ends on an upbeat note. Great book.
     
  8. Trippy ALEA IACTA EST Staff Member

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    It is a truely awesome book.

    I always liked the description "A ducks eye view of a shotgun blast".
     
  9. John M Registered Senior Member

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    Not so fast

    That an asteroid collision occured that may have produced the buried crater, as intepreted, off Yukatan is evident. It is also evident that this event took place near the time the already declining dinosaurs and other Late Cretaceous fauna became extinct. It is therefore probable, and maybe hightly probable that an asteroid impact was the cause of their final demise. But lets remember, correlation is not necessarily causation.


    Science does not progress by quantity. The opinion of 41 scientists should be taken no more seriously than that of 21, 10, or even just one, barring the evidence presented. There seems to be a trend to have mutliple authors attached to scientific publications, as though their weight increased its meret. In all probablility such ac article was written by the first two or three, if that, with the rest simply having their names attached. I can't say this is the case of the panal that concluded that an asteroid impact was absolutely the cause of the final Cretaceous extinction, but I'd be suspiceous. Nature does have her way of refuting dogma of any kind.
     
  10. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Until a plausible mechanism is found, it still has only correlation, not causation. Didn't a few of the dinosaur species extend a few hundred thousand years beyond the KT event? How did everything else (including human ancestors) survive if it was such a terrible event? A plausible causation mechanism is still lacking.
     
  11. sifreak21 Valued Senior Member

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    i havent read the first one.. but people always talk about this extinction.. when there was one far greater millions of years before yet no one seems to recognise it
     
  12. Trippy ALEA IACTA EST Staff Member

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    Right...

    Because it has to be about dogma it couldn't possibly be about the volume of literature that needed to be sifted through, the range of disciplines that are involved, and an attempt at providing balance through opposing view points?
     
  13. Trippy ALEA IACTA EST Staff Member

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    Plausible mechanism for what?

    You don't think that the causal mechanism proposed for a K-T impact are sufficient?

    So what if they did?

    Small size became a survival trait, more or less.
     
  14. Trippy ALEA IACTA EST Staff Member

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    Do you often comment on things without first reading them?

    The largest mass extinction, in terms of species wiped out, was the Permian mass extinction, there has been a great deal of research done on that as well, and a cause has been identified (essentially involving deep anoxic ocean water).
     
  15. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Many, if not most, of the dinosaurs were small. So why did small dinosaurs die out but other small reptiles survive (not to mention the mammals and birds)?

    There is a lot of literature showing a lack of causation between the KT event and the extinctions. There is a strong suggestion that it simply became a tipping point for events that were already under way.
     
  16. Trippy ALEA IACTA EST Staff Member

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    Why don't you look into the literature for yourself.

    But there is one simple answer - those species that survived, survived because they had some traitthat was advantageous under the circumstances (for example, as well as being small, the mamals had the advantage of being warm blooded).
     
  17. Neverfly Banned Banned

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    I, for one, would love to see all this literature.
     
  18. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    That first sentence is a generalism that is always true of evolution. We know that.

    Lizards/snakes are cold-blooded and they survived. Amphibians are cold-blooded and they survived. The list goes on and on. How did not being warm-blooded not make them survive, if they were not warm-blooded. There is some evidence that even some dinosaurs were possibly warm-blooded.

    Same is true with all of the other distinctions (egg layers survived, marine creatures survived, etc.) What attribute of dinosaurs caused them to go extinct because of the KT event. Can you name it? Otherwise it is just conjecture that the event caused the extinction and it is not merely correlation.

    ================
     
  19. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    Better start googling and reading, 'cause it's out there and I don't have time to do your homework.
     
  20. Trippy ALEA IACTA EST Staff Member

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    First off, I used warm bloodedness as an example, you also miss the point that just because one warm blooded animal survived, it doesn't mean that every warm blooded animal will survive.

    Secondly, whether or not it's a generalism is irrelvant to the discussion.

    You seem to be under the delusion that it was only Dinosaurs that were wiped out by the K-T extinction.

    This is false.
    54% of Diatoms did not survive the transition.
    60% of Scleractina coral did not survive the transition.
    98% of colonial coral species that inhabited warm shallow water did not survive the transition.
    Ostracode diversity reaches a minimum around this time.
    Coleoides and Nautali were the only Molluscs to survive the transition.
    35% of Echinoderms did not survive.
    Cephalapods and bivalve diversities were significantly dimished across the K-T transition.
    Inoceramids and Rudists also became extinct.
    20% of Cartiligonous and 10% of Teleost fishes became extinct (There's evidence for a Teleost mass kill in Antarctica at around this time).
    Insect numbers and diversities appear to have remained depressed for 1.8million years after the event.
    There's evidence of mass dieoffs in terrestrial plants, although not nececssarily a high tunover of species - having said that, 57% of North American terrestrial plant species did not survive the transition.
    Amphibiamns survived relatively unscathed, this is generally attributed to their ability to build burrows beneath sediment, rocks, soil or wood.
    All of the Corcodile species that survive, except for one, are freshwater species (the one exception being freshwater and marine), and none of the large crocodile species survived.
    Avian dinosaurs are believed to have survived because of their ability to seek shelter in marshlands, and dive or swim, however even here, before the K-T transition there were three major clades of avian dinosaurs, and only one of them survived (Neornithes survived, Enantiornithes and Hesperoninthes did not). Hesperoninthes was highly specialized, and one of the differences between Neornithes and Enatiornithes is the layout of the shoulder.
    Even Mammals did not survive unscathed, with Marsupials disappearing from North America, the Deltatherodians disappeared from Asia.
     
  21. Trippy ALEA IACTA EST Staff Member

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    Yes, and apparently you don't even have the time to do your own homework.
     
  22. Walter L. Wagner Cosmic Truth Seeker Valued Senior Member

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    I was under no such delusion, and I was well aware that portions of large orders of animals went extinct other than dinosaurs.

    What is still not explained by you is how that particular event caused those extinctions. For example, why did half of the diatoms survive? Why did other marsupials survive? Why did 65% of starfish survive?

    I am well aware of the conjecture regarding the event, but it still has not been explained in any straight-forward cause/effect method.

    I find the other extinction events of massive asteroid impacts billions of years ago (following conjectured planetary collisions) as I've posted about previously to be more convincing.

    And yes, I can well imagine that an asteroid impact could trigger a global climate change, and that a climate change could then trigger extinctions, and having a strong correlation between the two over the course of millenia. But as for the sudden and rapid demise of dinosaurs and other species in the course of days following an asteroid impact, I'm still waiting for the cause/effect showing thereon.
     
  23. Neverfly Banned Banned

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    You seem to be ignoring just how large this impact was for one.

    Hypocritically, you ask for explanations and then complain about conjecture. Make up your mind.

    Trippy seems more knowledgeable on this topic than I am and I do not intend to speak for him; but you strike me as in a state of denial what is presented.
    I see a lot of obfuscating and no real presentation of anything tangible from you.

    In evolutionary terms, survival is a game of chance. It would be speculation and conjecture to observe the traits of survivors and try to deduce what traits each had that allowed for their survival, or what environmental conditions we may not know about favored them.

    However, it seems that if you're going to demand explanations and conjecture, I can too (Although I shouldn't...): how do YOU explain the 'sudden' extinction event that occurred at the same time as a very massive impact?
     

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