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Science

Dinosaurs Never Held Heads High 217

Posted by Hemos from the shedding-new-light-on-things dept.
richard_za writes "The common notion that long necked dinosaurs held there necks high to graze from treetops has been proven impossible. Roger Seymour, from Adelaide University's Environmental Biology Department and Harvey Lillywhite from the University of Florida. According to a research paper published at the Proceedings of the Royal Society in London, he explained that due to heart size and metablic rates the only way they could have functioned on land was with a horizontal neck. This flies in the face of images popularised in Hollywood movies such as Jurassic Park. However it is doubted that this new evidence will have any effect on the Mozilla Project."
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Dinosaurs Never Held Heads High More

Dinosaurs Never Held Heads High

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  • mozilla will be affected most of all (Score:5)

    by VAXGeek ( 3443 ) on Tuesday November 07, 2000 @05:31AM (#642396) Homepage
    actually, mozilla will be affected most of all. they do have the slowest metabolism rate out of any open source project i've ever seen.
    ------------
    a funny comment: 1 karma
    an insightful comment: 1 karma
    a good old-fashioned flame: priceless
  • This story is unbelievably old. Has anyone been to a display of dinosaurs bones in a museum lately? They are all displayed with the neck horizontal now. Or is your primary source of information cartoons? :)

  • Am I the only one... (Score:3)

    by NecroPuppy ( 222648 ) on Tuesday November 07, 2000 @05:32AM (#642398) Homepage
    ...who thinks that a story about dinosaurs is somehow appropriate for election day?
  • I would think it would be harder to hold their neck straight out rather than up. How do they know that they didn't have bigger hearts that could handle pumping the blood up there? Or maybe some additional smaller hearts to help it along. Maybe I missed the point
  • I dunno, it just doesn't seem right. You try holding your neck horizontal for a while. After a few minutes your heart will get strained from the effort and you will go back to vertical. It just doesn't seem right.
  • Do you guys even proofread? I learned the difference between those two words in the FIRST GRADE.
  • what election day? I think I would have seen political posters of Wim Kok, and the 'socialistiese partij' (note spelling), who are against it. the world doesn't stop just because some country has elections today.

    //rdj
  • I'm a far cry from a dinosaur expert, but I remember seeing a Discovery [discoveryeurope.com] program about this about a year ago...
  • this just goes along with a general unifying theory i've been hearing for a while. people used to be shorter. dinosaurs couldn't hold their heads up high. obviously, the sky used to be lower. the firmament is rising, and with grows our distance from the lord.
  • Perhaps they just need a self-help videotape to boost that self-esteem?

    Buck up, little T. Rex, it's all right..

    Whew, bad joke. I can practically smell my karma burning.. :)

    Sid

  • Four chambered hearts (Score:3)

    by Epeeist ( 2682 ) on Tuesday November 07, 2000 @05:39AM (#642406) Homepage
    I went to a seminar in Manchester a couple of years ago where it was argued that long-necked dinosaurs must have four chambered hearts.

    Apparently if they had two chambered hearts then when they bent down to drink the hydraulic pressure would have made their heads explode.

  • Reality and fiction (Score:3)

    by iamsure ( 66666 ) on Tuesday November 07, 2000 @05:39AM (#642407) Homepage
    Lets step back for a second before we bash Crichton. In Jurassic Park, he was one of the first authors of popular dinosaur fiction to display VERY controversial, and very relevant theories.

    Like what?

    Like the familial instincts, like the pack hunt, like the individualism of some species, etc.

    Sure, the movie dumbed some of it down, but book was really very groundbraking, and the sequel was even better.

    We have to understand that authors have to capture both the truth AND the common perception of things, and try their best to balance them.

  • oh really (Score:5)

    by Anonymous Coward on Tuesday November 07, 2000 @05:40AM (#642408)
    As somone with a biology background, if you studied the skeletal remains of a giraffe you might think the same thing. Due to the fact that I don't think there has ever been enough soft tissue find that could irrefutably say that these animals did not have valves for blood flow in their necks. I mean for goodness sakes they still are divided on if they were poikilothermic or homeothermic, if they were endotherms or exotherms...so given we know very little about their metabolism anything based on metabolism is a best guess at best :) Ok ok I did take 2 semesters of classes on dinosaurs.... Anyway just kinda found this one ridiculous.

  • Proven? (Score:3)

    by AlphaHelix ( 117420 ) on Tuesday November 07, 2000 @05:40AM (#642409) Homepage
    Nobody ever "proves" anything in any science. Particularly not when making speculative calculations about millenia old animals about whom we only have fossil information.
    * mild mannered physics grad student by day *
  • I seem to recall that scientists have conclusively proven that bumble bees cannot fly (wings too small, body too heavy...). Apparently the laws of physics don't apply to bumble bees. Or something.
    ___

  • Poo poo

    Giraffes have the same problem. When they bend down their part their front legs which squeezes the main artery to the brain to stop it blowing up.

    Gary

    (Image a beowolf cluster of those!)

  • Walking with dinosaurs [bbc.co.uk], a program on the bbc, had this story as well; they based it on a computer model showing the unnatural bending required for some dinosaur necks to achieve the classic cartoon stance.
  • it's all about the size of the heart. If the heart is not big enough to pump gallons of blood 30' into the air (and that's a really hard feat) then a dinosaur would pass out when it lifted its head.

    Think about it -> how often do you grey out a little bit when you stand up too fast? Or, when you cut your finger, didn't your mom tell you to hold your hand above your head? That was to prevent as much blood from getting there, because the heart can't pump it up there as easily

    By the way, if you're really careful, you can sometimes see the impressions of soft tissue as well as the bones in fossils. Also, it's fairly safe to assume that, being closely related to today's reptiles, dinosaurs would have only one heart. The only thing I know of that has more is an earthworm (5 hearts), and those aren't really hearts, just parallel tubes that contract to pump blood.
  • I haven't studied dinosaurs since elementary schools. I remember learning that some dinosaurs -- especially the larger, foraging vegetarian ones -- had long necks to reach otherwise inaccessible foilage.

    I wonder if the assertion mentioned in this post applies to some of the heftier dinosaurs, like the Brachiosaurus. If I remember correctly, the Brachiosaurus possessed an extremely long neck and was fond of submerging itself up to its head in water. According to this theory, the increased buoancy allowed the Brachiosaurus greater freedom of movement.

    Sincerely,
    Vergil

  • This article [mb-soft.com] addresses a few more interesting things as well.
  • ...they probably held their heads upright, but scientists aren't sure. They're still researching it, but, if you keep visiting the website, chances are, you'll see something posted there about it sooner or later.

    - A.P.

    --
    * CmdrTaco is an idiot.

  • ..long necked dinosaurs held there necks high..

    If you had the brain the size of a walnut, and needed an extra brain in your ass just to get by, you wouldn't be all that proud either, would you??

    "There's a party," she said,
    "We'll sing and we'll dance,
    It's come as you are."

  • This is a link to the publication [royalsoc.ac.uk]

    You want the Oct. 7th 2000 issue.

    Of course you can't read it without a very expensive subscription.

    Here's an idea for story submissions... how about not posting stories where the details aren't available to the mass public. There are plenty good story submissions which are ignored and everyone can read the details.

  • It will it a certain idiot gets elected. Have you ever seen the "Land of confusion clip" from Genesis? I'll take Kok over that any day, or Rosenmoller for that matter...
  • Appart from this fact that this "news" is older than the human race itself. I saw a program on this topic aired on discovery channel couple of months ago. Which means its well above two years old.
  • The main thing that pissed me off about the movie is the fact that they took DNA from a frog to patch the missing pieces. Birds are the closest living relative to the dinosaurs. I also think that the story about Stephen Jay Gould asking Crichton why he put a dinosaur not from the Jurassic era on a book titled Jurassic Park.

    Harlan Ellison says never write down to your audience, make them look shit up. It is unfortunate that hollywood can not embrace this simple philosophy.
  • Just itchin' to link to the imdb?

    --

  • Actually, Bumble bees can fly. It just has to be explained with vortex aerodynamics, not linear aerodynamics.

  • Not only that, but it's clear they've been holding their heads low for a long time now. Take a look at the latest article posted to Mozillazine [mozillazine.org]. Pathetic, childish drivel that'll put the average Slashdot Troll to shame.

    And THESE are the people we'd trust with the future of online communications?

    Anyway, to bring things back on topic. It's a wonder how much we know about dinosaurs to be exact fact? Who knows what future Earth-dwelling races will extrapolate from our remains?

  • I couldn't find a link to anything about the research paper richard-za mentioned, however I did find these, which are (sort of) on-topic:

    http://www.bearfabrique.org/s aur opods/sauropods.html [bearfabrique.org]
    http://www.talkorigi ns. org/faqs/sauropods/sauropods-misc.html [talkorigins.org] (The section "Blood pressure would have been too high", especially)

    Anybody got a link to something more recent?

  • Michael Crichton (author of Jurassic Park and its sequel The Lost World) realized this error - in the book The Lost World he corrected this as sort of an aside - not only would dinosaurs be forced to hold their heads horizontally due to blood flow, but also due to balance. The example given in the book was of a suspension bridge - in order for these dinosaurs to simply stand, they would have to have their long necks horizontal to balance out against their long and heavy tails.
  • Rubbish! This is a well-known urban myth: what has been proved is that, according to the extremely well-known equations governing fixed-wing craft, bumblebees cannot fly. But (dur!) bumblebees aren't fixed-wing craft. This demonstrates how wildy different the rules for moving-wing flight are - and no-one really knows what they are, 'cos they're massively non-linear.
  • But these dinosaurs were willing to stick their necks out.
  • a palentologist friend of mine informs me that it is accepted thought, and has been among members of his discipline for at least as long as he's been studying it (5 years) not only based on metaboloism but on probably diet, balance and bone structure. t.
  • The sauropods in Jurassic Park were brachiosaurs, and they're pretty much designed to have upright necks - their forelegs are longer than the rear legs, so its head has to be higher than its heart unless there was a huge kink in its spine - ISTR the theory being that it had a big muscle in its neck that acted like a blood pressure collar which forced the blood upwards...

  • Imagine all the graves containing bones, silver teeth and silicon breasts. This will display a very accurate picture of the human race:-)
  • ...at least not according to classical models of aerodynamics. See this October 97 New Scientist article, "On a wing and a vortex [newscientist.com]":

    ...Conventional aerodynamics--used in the design of aircraft and helicopters--rely on "steady-state" situations such as a fixed wing moving at a constant speed or a propeller rotating at a constant rate. By contrast, the motion of insect wings is a complicated 3D affair. Nevertheless, until recently researchers were not convinced that this special motion could generate any unusual sources of lift. For years, they struggled to explain insect flight using a theory rooted in steady-state situations, not understanding why their aerodynamic sums didn't add up. Ellington summarises it neatly. "Since the 1950s, we've been looking at insect flight with the wrong picture in mind."

  • When they bend down their part their front legs which squeezes the main artery to the brain to stop it blowing up.

    How the HELL does something evolve like that? Like, does one giraffe look at another giraffe exploding and thinks "Hmm, maybe if I wibbled my legs apart a bit further I might be able to get away with it?" Are animals THAT self aware?

  • You want the Oct. 7th 2000 issue.

    Did you mean the September 22nd [catchword.com] issue, maybe?

  • Sure the dinosaurs held their necks horizontal, but did they look up and fall over backwards when a teradactyl squacked overhead?

    Teradactyls could have been a contributing factor in the death of dinosaurs.
  • Probably because your body isn't built like a dinosaur's.
    ----------
  • Ok, so this guy has 'proven' that dinosaurs could not have held their heads high. This begs the question: why the hell did those dinosaurs have long necks in the first place?

    Evolutionary theory tells us that environmental pressures lead to some trait shift in a population. I'm guessing that since they could not use their long necks to reach high foilage, then the logical answer to why the long necks is to give the carnovaurs a bigger target. Or maybe it was to counter balance their enourmous tails?

    Without a living animal to ask, how do these scientists 'prove' anything with a straight face?

    ---

  • While it may be that dinosaurs had a horizontal configuration, I don't think that you (or in fairness, the article's author) can really say it has been "proven".

    The unfortunate fact is that with all respect to the science goes into paleontology (and archeology for that matter) there is always so much that is not known that what is missing is often filled in with conjecture and story telling. Given the limited information, you can build a scientific model to "prove" almost any theory you wish to start with.

    To further blur the issues, those models are not always accurate. Once upon a time it was "proven" than a man could never run a four minute mile. They looked at blood flow and O2 capacities, and determined that it was flat out impossible. Now it's a somewhat common occurence...

  • Sometimes I think I'm the only person on the Internet who knows the difference between "there", "their", and "they're". It's good to see someone else who is educated in basic grammer.
    ----------
  • Doh!

    Good call. I see you also figured out how to get a specific table of contents, something that I gave up on. :)

    I bow to your superiority! >:(

  • I'm going back a long way, here. Trying to remember my grade 10 biology class when we dissected a locust. I mostly remember the smell. Yuk. Anyway, back on topic: IIRC, insects don't really have a well developed cardiovascular system at all. Their internal organs just float around in a sea of "blood" which is circulated by several valves that just squirt it everywhere. Please correct me if I'm wrong.
  • I doubt this story. According to the article its impossible for them due to heart and brain size. So far all we have found from the dinoraurs are mostly bones; how did they discover the size and the 'capacities' of the heart of these dinosaurs? Did they also 'asume' that the maximum capacity would be xxx (fill in your amount) ?

    The reason why I think this story isn't true is relevance. In nature everything is there for a purpose. Offcourse we humans did things the other way and made our own tools, but animals have all the natural 'tools' they need to survive. Giraffe's have a long neck in order to reach their food, lions & tigers have sharp claws and teeth to kill and rip open their food, etc, etc. Everything is there for a reason.

    Having a long neck for, say, 5 meters and holding it horizontal not only takes extremely more effort to maintain; it also doesn't make any sense what so ever. Why would they have a long neck when their head is close to the ground anyway? To look cool and being able to eat grass which is 7 meters away? I don't think so Tim.

  • AFAIK The IE team started with an already stable product (Spyglass Mosaic, itself based on NCSA Mosaic). Mozilla is a from-the-ground-up project.

    But you're right that IE is a better browser: they made the (IMHO correct) decision to make a browser and a browser only: they left the mail client (for example) to the Outlook team, etc. Mozilla could learn from that.
    --
  • How the HELL does something evolve like that? Like, does one giraffe look at another giraffe exploding and thinks "Hmm, maybe if I wibbled my legs apart a bit further I might be able to get away with it?" Are animals THAT self aware?

    No, it's just that the only giraffes that lived long enough to procreate were the ones that displayed that behaviour. This is probably an instinct that is passed along genetically. Basically, any giraffes with the "wrong" instincts didn't live long enough to pass them on. What we end up with is all giraffes doing the leg spread :)


  • Way back I was reading up on theories of a more dense water atmosphere. I can't remember the exact name, but the theory was that during the dinasour era the humidity was extremely high compared to todays limits. This extremely dense water vapor environment would be the only type of environment that a Paradactal (sp?) could fly in due to the airodynamics of its wings.

    Would such an environmental difference, if it were to exist, affect the hydrolic nature of the heart such that dinosaurs could walk with there heads high?
  • Focus group results indicate that consumers in the 3-16 age range prefer dinosaurs that hold their heads high. In light of this data dinosaurs in movies and action figures will continue to be depicted as hold their heads high regardless of scientific fact or heresay.

  • Am I the only one who thought those mueseum displays where horizontal to save construction costs of a hugely high ceiling? I guess it always made sense to me. Nice to know there is a real theory behind the decision :)
  • Thank you!
  • Giraffes also have an organ at the base of their brain which helps choke off the blood pressure, because just the pressure of the column of blood in the however-many feet of neck above their heads would do them in otherwise (think the rush of blood to your head when you hang upside down, only lots worse).

    Jon
  • If you had the brain the size of a walnut, and needed an extra brain in your ass just to get by, you wouldn't be all that proud either, would you??

    What?

    When did we start talking about MCSEs?

  • So they could have a large grazing area without moving.

    Moving that huge body a step forward to take a bite of grass would have been inefficient, wherewas a huge neck would let them stand still and graze a large area.

    Thad

  • And of course, giraffes didn't start with necks like they do now; it was a process of gradual increase in height coupled at various points with the different adaptations that make life with that long a neck bearable.

  • Re:oh really (Score:3)

    by Bilbo ( 7015 ) on Tuesday November 07, 2000 @06:12AM (#642453) Homepage
    Seems that every few months we see yet another SHOCKING DISCOVERY about dinosaurs and how they lived. Everyone has his pet theory, and the more controversial, the better. The truth of the matter is, we don't have a clue!

    Let's face it. We're looking at old, scattered fragments of bones. We can come up with some interesting theories, mostly by comparing ancient bone fragments to more modern species, but they are still people making long shots in the dark. Worse yet, factor in peoples' natural tendency to seek the limelight with some "ground breaking" new theory, and you see why we have these "new" theories cropping up all the time.

    --

  • You mean Jurassic Park isn't scientifically accurate? SCANDAL!
  • You, sir, are in violation of Article 2 of Slashdot patent #535, Techniques for Enhancing Score of a Credibility Metric of Electronic Forums [slashdot.org]. You must cease this violation or pay the appropriate licensing fees.

    I suppose you would also lick Bill's boots if they tasted like ice cream?
    --
    Bush's assertion: there ought to be limits to freedom

  • Also, (Score:1)

    by uradu ( 10768 )
    "its" and "it's", and "then" and "than", and "and" and "end". Ok, strike the last one.
  • Relative to a human, take a 10 pound book, and hold your arms out straight for 10 minutes.

    Now hold your arms up and out, not straight up.

    Which can you hold longer? It's all about leverage. A dinosaur would find it NEARLY impossible to hold it's long neck out straight for hours on end.

    Can a SNAKE stand straight out for hours? No. For short periods of time, yes, but mostly, it'll shoot it's head up in the air.

    This study is bunk.

    Reminder: Since we don't have a sauropod heart to examine, we have NO idea how good it's circulatory system was. We're extrapolating from elephants and giraffes.

  • Of course, the heart size and metabolic rate of dinasaurs is not known. Scientists can guess (hypothesize) about these things, but in the end we really do not know.
  • One paper may have "proven" this, but I'd wait a few years before I started believing it. Let's see what the others in their field say about the research, or whether other counter-theories are advanced, etc.

    It's easy for one research paper to be wrong.

    Of course, irresponsible persons in the mass media will immediately run the story as if it had come down from Mt. Sinai on stone tablets, but you have to remember that they're peddling journalism, not facts.

    Jon Acheson
  • given your own example of the earrthworm, who's to say that perhaps long necked dinosours didn't have similar contracting arteries to help the blood reach their head? Or perhaps... look at how a red wood is able to get it juices hundreds of feet in the air... check valves. Check valves could go a long way in helping in that dept.

    just a thought...

    BillyZ
  • Yeah, it seems that a lot of time has been spent wondering who shot Kennedy, and it seems that a more important question has been neglected: why didnt they kill Nixon, Reagan or Bush?
  • We didn't. MCSEs' *only* brains are in their asses.
  • It wasn't printed on paper, and it wasn't signed in ink. Furthermore, there were no witnesses, and there was no challenge period as mandated by the U.S. Patent Offices.

    And I suppose that you believe that "hokey-pokey" patent [slashdot.org] to be legitimate as well.

  • Re:oh really (Score:5)

    by Anonymous Coward on Tuesday November 07, 2000 @06:23AM (#642464)
    Hi, here is another one, who teaches zoology at the undergraduate level.

    You are right. This article and its arguments are crap.

    The giraffes have a blood corpuscle (like a fine branched network) which helps to relieve the pressure above (i.e. closer to the head) that network. This way the giraffes' heads don't explode from the water column when it leans formard to drink water.

    Of course they were homeothermic:

    1: The fine canals inside bony tissues are of a kind only found in the warm-blooded mammals and birds, but not in other amniotes like crocodiles, lizards, snakes, or turtles.

    2: Birds are dinosaurs, in the same manner as bats are mammals. The are thus strong reasons to believe their most proximate ancestors also were warm-blooded. [Somewhat circular]

    3: Erect posture. You just cannot walk upright for long distances, lifting your own body weight, unless you have the metabolism for it.

    4: Proportion between predators and prey. In current, homeothermic ecosystems (like the African Savannah) there are about 1-5% predators in terms of body mass. In ecosystems dominated by cold-blooded predators (crocodiles or large varans) there may be up to 30% predators. In Perm, before the dinosaurs, the predators were about 10-30% of all fossils. During Triassic, Jurassic, and the Cretaceous the predators sank to 1-5% of the fossils in terms of (estimated) live body mass; the same is true for mammalian dominated fossils more recent.

    Cheers!

    Erect and long!
  • Thesis: We propose that Earth was a satellite of Saturn, or more correctly a body which the ancients identified as Ouranus and which we shall refer to as proto-Saturn. The present day Saturn is all that remains of the once larger primary which we orbited as the closest and innermost satellite [1]...

    http://www.bearfabrique.org/Saturn/ianT [bearfabrique.org]

    -l

  • Imagine a Beowolf cluster of Giraffes that have forgotten to "spread their legs" (sorry ladies) when drinking (or is it after drinking, ladies?) and their heads all exploding?

    Even better, imagine Linux Torvalds head explode due to thinking too hard.

    Gary

  • That's certainly one of the obvious possibilities, but the truth undoubtedly much more complex.

    There are going to be many beneficial and detremental aspects to any genetic feature, and which of those dominate is going to change over time. Many features start out with one primary purpose/benefit which then gets subsumed over time by an alternative use as the environment or other factors change. For example, ears evolved from gills, and while ears no longer help us breath underwater, gills surely did have some benefit in picking up vibrations... Similarly a long neck may have evolved primarily under selective pressure as an efficient way to get rid of body heat, then over time the benefit of lazy grazing may have become more important, finally (in times of plenty, say) to become more important as a means sexual attraction.

  • This is going to invalidate most of the household appliances and technology on the Flintstones, except for the clamshell shaver.

  • This is simply ridiculous. Why would a dinosaur have a long neck if it was not going to use it for any purpose? Evolution rarely encourages traits that have no function, particularly one that would create such a huge negative surivivability trait -- slows them down, more mass = more food required, more awkward to escape predators, etc.

    This guy must be a Libertarian -- all focusing on the theoretical details, no focus on the objective, practical reality :). [Hey, gotta use some election day metaphors!]


    --

  • Speaking of basic grammar --

    EVERYONE PAY ATTENTION NOW!!!!

    THE WORD "IT'S" IS A CONTRACTION THAT ALWAYS MEANS "IT IS"! IT IS NOT THE POSSESSIVE FORM OF THE PRONOUN! THE POSSESSIVE FORM OF THE PRONOUN IS "ITS"!

    WHEN YOU WANT TO SAY THAT SOMETHING THAT IS NEITHER MALE NOR FEMALE OWNS SOMETHING, YOU SAY "ITS"

    CORRECT: "It's making me sick how many times I have seen people screw this up." read this as "It is making me sick".
    CORRECT: "The dinosaur cannot lift its head up."
    INCORRECT: "The dinosaur cannot remember it's root password." try reading it as "The dinosaur cannot remember it is root password."

    (I am so sick of people making this mistake)
  • ... in the sequel to JP, The Lost World (the book, not the horrible movie "based" on it), Chrichton talks about the same topic. If I recall, he (through his characters) claims that the whole point of a long neck was to counterbalance the long whiplike tail, which was a very effective weapon against attackers.

  • Not "proven" or "impossible" (Score:3)

    by Medievalist ( 16032 ) on Tuesday November 07, 2000 @06:37AM (#642472)
    OK, first of all this is an old argument. No conclusive "proof" available at this time for either faction.

    There are several possible anatomical features that would invalidate the math used: for example, the long-necked dinosaurs could have valvular tubing (either traditional valves like a giraffe, or structures similar to Tesla's valvular fuel piping) in their necks. There could also be muscular arrangements for peristaltic pumping and flow control - the peristaltic pumps in mammals are weak, but that doesn't prove anything about dinosaurs. I am not aware of any complete soft-tissue fossils of dinosaur necks that would prove or disprove the existence of such structures - post 'em if you got 'em.

    Other arguments have been made as well - for example, if a brachiosaur can't lift his head for any length of time, he can't drop it for any great length of time - the blood would pool in his brain (rapidly, since the efficiency of his heart as a suction engine is likely much poorer than as a pressure generator). So, given that such a huge creature would require tremendous amounts of fluid intake, how did they drink without passing out? The fossils don't cluster around waterfalls as far as I know (again, post 'em if you got 'em).

    Now, as computer geeks, we're all supposed to have some familiarity with LOGIC. So we should all know that it is nearly impossible to PROVE a negative - and astronomically more difficult to do so when the bulk of the evidence is obscured. Most paleontologists agree that the fossil record is necessarily incomplete due to the unusual circumstances required for fossilization and the tremendous variance of species diverisity over geological time periods.

    --Charlie
  • If I was you I would be interested. Because whoever wins the United States presidential election will have unlimited access to the worlds largest stockpile of nuclear weapons, as well as the most powerful conventional military forces the world has ever seen. He will also be in a position to make trivial daily decisions which influence the economy of the entire world.

    Whatever misguided hubris you may feel regarding your own states importance is irrelevant; the most powerful, prosperous and influential country in the world is about to change its leadership, and that is a pretty newsworthy event.
  • It seems as though the most important question at this moment is: who is going to shoot Bush Jr.? Volunteers?

  • I went to Mozillazine to read that article. The guy has a point. It sucks to get flames when you're developing as well and fast as you can. Especially from people who haven't contributed a single line of code to this Open Source project.

    Having said that, go and contribute. Fork the damn thing if you have such a problem trusting these people. Or go use some other program.

    The Mozilla guys don't own you anything. They don't work for you and they certainly don't have to prove themselves to a whiner like you.

  • Insects (arthropods) do have an open hemocoel in most of the body cavity, but there is also a proper circulatory system, with heart and arteries.

    Insects only have one heart, a tubular muscle that pumps blood forward into the head, whence it diffuses into the other bodily tissues.

    MJP
  • > But you're right that IE is a better browser: they made the (IMHO correct) decision to make a browser and a browser only: they left the mail client (for example) to the Outlook team, etc. Mozilla could learn from that.

    Well, the mail client did not really add delay to Mozilla (because it was a separate issue). Galeon is, for instance, a mozilla-based browser that have no mail or news. OTOH, Netscape is a mozilla-based browser that will have this all-in-one approach.

    Wihle I agree with you that it was a bad idea, it worth noting that the mail/news/browser/all-in-one is pretty much a requirement for AOL and for embedded markets.

    Lastly, the XUL thingy will turn mozilla in an incrediblely powerfull platform (or a shitty mess, depending on how you look at it).

    Anyway, I now use Mozilla more often than IE. Shift-Wheel to increase/decrease font size is quite nice...

    Cheers,

    --fred
  • Even if its heart can't pump blood at that sustained level, there's no reason why it can't fling its head up briefly, grab a branch, haul it down, and eat it at ground level (provided there are appropriate constrictive muscles for preventing a temporary blood-pressure drop during the process). And you wouldn't need entire new hearts; simple bloodvessels can constrict in time with your single heart and provide much of the same function. (just look at your pulse, for instance.)
  • as in some news article posted on slasdot before..
    what if the gravity was low back then..
    would they still be able to keep their heads high
    or would they fail miserably
    crushing their necks since they are long and
    it would take very strong muscles to keep them horizontly
    as everybody knows that keeping hands horizontly
    extended requires more muscle toughness
    than keeping their hands extended vertically
    as in giraffes
    just my imagination..


    "The world is coming to an end. Please log orff."
  • Not sure about the rest of this study, but thought this needs addressing..

    Yes, it's hard for a human to hold their arm out with a heavy book.. that's because your arm wasn't made to be held in that position for many hours. Ditto the snake. Now, look at the bones of a long-necked dinosaur, you'll see they're designed exactly like the ribs of a suspension bridge. A thick band of muscle traveled along the apex, like the main suspension spans of the Golden Gate.

    As for whether they held it horizontal or vertical most of the time, that's beyond me. But it's clear they did hold it horizontal at least part of the time, and it had evolved to accomodate such a configuration. (I also might add that the majority of the weight was at the base of the neck, not the head)

    Just because your anatomy cannot accomodate such a position, doesn't mean theirs couldn't. After all, can you produce enough lift by flapping your arms to fly? A bird can, and that's because it has the hardware to do it with, namely a massive set of pectorals that often make up 40% of its body weight.

  • there's no reason why it can't fling its head up briefly, grab a branch, haul it down, and eat it at ground level (provided there are appropriate constrictive muscles for preventing a temporary blood-pressure drop during the process).

    Great! Now I have this image of a huge field of tremendously large thunder lizards all flinging their heads up to rip off a branch to eat, tearing it off, then instantly passing out, landing on their sides in a big cloud of dust.

    A half hour later, they wake up, stand up shakily, and contentedly start munching on their branch.

    Somehow they've lost some of their graceful appeal now.

    --
    Evan

  • Wrong wrong wrong. There is no proof of anything. There is no way to prove something like this. In fact, there is no way to prove most things in science, and I believe it was my eighth-grade science teacher who told me "In science, there are no proofs. There are good theories, and there are bad theories." This is just that -- a theory being put forth by this one paleontologist. It is nothing more than a theory, nor will it ever be.

    --

  • Wouldn't you expect a few screw ups like an extra half formed arm that didnt do anything. We'd all survive, we'd just be a little messed up.

    In order for the person with the half arm to pass it on, they would have to have sex with someone. Given the choice of having sex with someone who has two and a half arms and another person who looks normal, what would you choose?
  • I mean, really. Imagine the accidents that would happen if they had had their heads just snaking through the grass. It'd be worse than being a python on a highway...


    --
  • >1: The fine canals inside bony tissues are of a kind only found in the warm-blooded mammals and birds, but not in other amniotes like crocodiles, lizards, snakes, or turtles.

    Aaaah, but a study was done that showed these canals CAN exist in cold-blooded animals because they area created based on activity, which is usually higher in warm-blooded animal, but not exclusivly. Monitor lizards but in a tred-mill developed these canals, while monitort lizards at normal activity levels did not.

    Other than that I can't disagree with you.
  • Many important biological issues are brought up by the gigantism of dinosaurs. Many people have theories that they were not erect, or smart, or fast, or land-based, or that they were warm or cold-blooded. But they are just theories. Nothing will be proven until we actually see one in action. Other than birds, we simply do not have any huge lizards around to find out about.

    Also, millions of years ago, we believe the air was much warmer (which might have led to more land being underwater, or not). But, the air pressure may have been vastly different, the tree height different, the foliage different, the predators different. We don't know, except that probably a lot WAS IN FACT different from how the Earth now is.

    So until we know the basics, like ambient air pressure, we cannot know what the dinosaurs were like. (If the air pressure was higher, and therefore the atmostphere thicker and more bouyant, then gigantism would be easier to achieve.)

    Maybe not. We don't know.

    -Ben
  • I especially like the theory that dinosaurs were actually feathered and ran around flapping their wings to achieve higher speeds. Not that I entirely dismiss the idea. I just think it is funny to imagine all these immense and fearsome creatures flapping around like so many chickens.
  • Wihle I agree with you that it was a bad idea, it worth noting that the mail/news/browser/all-in-one is pretty much a requirement for AOL and for embedded markets.

    No it isn't. The browser should have the ability to call these programs when it's required, so that when you click on a mailto: or news: link on a webbrowser, it calls the relevent program. This gives the user the chance to replace the mail/news program with their choice, and divorces the development of these tools from the browser.

  • While I agree with you, sometimes I feel like I need to pick a few nits... I also thought I'd provide a couple of explanations for that tiny population of non-biologists here on /. :)

    1: These canals are called Haversian Canals. They're formed when bones grow. The faster the bones grow, the more canals there are. Lizards and other traditionally 'cold-blooded' animals don't grow as fast as mammals and birds, and thus have fewer canals. They do have them though... just fewer of 'em. And when snakes and crocs are kept in zoos and fed often (like once a week instead of the once a month as in the wild), they grow much faster, and have more Haversian Canals. Dinosaurs all have lots of canals, suggesting that they grew to full size very quickly (5-10 years). And we sure as hell didn't keep them in zoos... This kind of growth suggests high metabolism = warm blooded.

    2: Birds are descendants of the Theropod dinos... most specifically, the line that created those raptors from Jurassic Park. Birds are warm blooded, and have 4-chambered hearts. Thus it's not unreasonable to believe that Dino's had the same. IIRC, there were also some finds that suggested that raptors had feathers (or some proto-feather type things). If you think that's wierd, think about this... An article published in a major scientific journal (I can't remember if it was Science or Nature...) reported that a paleontologist had found evidence that T-Rex had feathers as a juvenile...

    3: Erect posture has nothing to do with it. It's a function of joint angles, not metabolism. Yes, it's correct that lizards actually use less energy moving with their legs jutting out than mammal quadrapeds do with their legs under them. However, upright generally means more speed. But crocs are cold-blooded, and actually can use a 'half-upright' posture, where they keep their front legs splayed, but their rear legs upright. Damn crocs always messing things up with that funky biology of theirs (They've got 3 1/2 chambers to their hearts too...). Yeah, there's a slight correlation here, but I don't think it's significant.

    4: I've always been fond of this one. The argument here is that 'warm-blooded' predators require lots of food to survive and grow. In order for this to happen, there are generally lots more prey than predators. So, in the Permian (before warm-blooded critters existed), predators made up a much larger proportion of the total biomass. Dinosaurs, however, showed a much lower proportion, suggesting that they had high metabolisms.

    As for the article itself, there have always been people arguing this one... it's nothing new. And yes, they're probably right that, in the absence of mitigating factors (special organs) sauropods couldn't raise their heads up. However, there are lots of options as far as mitigating factors go. Paleontologists have suggested similar organs as giraffes, secondary hearts in the neck (actually just muscle thickenings of the arterial wall that squeeze after the main heart does), and other stuff. It's all possible, and can't be ruled out.

    Also, grass and flowers didn't appear until the late Cretaceous, long after the sauropods (brontosaurs, brachiosaurs, etc.) died off. The sauropods weren't swinging their necks around munching on grass. Why the hell would sauropods grow to such a large size to munch on scattered ferns?

  • If we found and studied one then the theory could be proven. Or disproved. Yes, it would probably require a jurassic-park like experiment to figure this out, but that may be doable. (or not)

    -Ben
  • Granted, if we actually had some dinosaurs, we could prove or disprove this theory. But my point was that since all the dinosaurs died millions of years ago and time machines exist only in science fiction, we won't be getting the chance to study real dinosaurs anytime soon. :)

    --

  • Ok, I'm going to go out on a limb and risk pride in saying I intuitively disagree with you. I've taken physics, but I don't deal with fluid mechanics (disclaimer). The "weight" of the water or air is totally irrelevant, as far as I can understand. It's the viscosity... resistance to movement that's different.

    When in water, you can lift much heavier things.. Partly due to boyancy, and partly because the dynamics of the fluid system can act like aerodynamic lift on steroids... Namely, movement in water will have a much greater lift than movement in air. This is because the same principles of flight are amplified in a thicker system (pressure differentials are more pronounced).

    Being independant of the validity of atmospheric differences back then, thicker air would not have "impeded" life forms back then in any way other than to slow them down. And in my admitedly limited knowledge in this field, it should enhance their ability for flight and even motion of larger beasts..

    The first part should be obvious. The second part, however, deals with the fact that they'd have a thicker cushion of air.. Greater resistance in the air acts like a soft pillow brushing against them.. Think about trying to run through water.. yes it's difficult - requiring lots of muscle / drag (which would facilitate an aerodynamic body even for ground creatures). When you run through water, however, you're less likely to fall flat down and smack your face hard against the ground, though thick air isn't as extreme as water. This property would enhance the life of massive creatures; It would deminish the negative effects of falling, and actually help them stand up (in the presence of any sort of breeze.. just as you can easily stand on your hands under water).

    In my mind (mulling this over).. If it were the case that we had denser air back then, then it could only have helped the development of avions. It is possible that animals needed size back then to live (I'd have to brain storm to qualify this more), they developed the aerodyanmics of fish, etc.. Features would help in the general lift of their heavy bodies (being able to attain some sort of lift even in the simplest of breezes).. Some actually advanced to the point of take-off, others simply had incredible jumping capabilities... As the air thinned (along with any other natural catastrophys), the creatures needed to shrink in order to survive. Those that didn't died out.. Those that were left were more than suited for air flight. The turkey must have been one of the straglers, too large in our thin our to fly, but wasn't too large to be naturally selected for extinction.

    Last time we talked about Dinosaurs, I was pointed in the direction of "Saturn Theory", which is an interesting mental exercize in physics.. It's also good to turn everything you know upside down on occasion, just to keep you honest... So here's the first link I could find.

    saturn theory [teleport.com]

  • Nice link -- but much is obsolete, or just plain wrong

    We now know what [uc.edu] finished off the dinosaurs and plesiosaurs.

    we have strong evidence that the dinosaurs where thriving [mpm.edu] up until the impact.

    as others have posted, the blood pressure argument only holds if the the circulatory system consisted of a heart and inelastic tubing - a fairly strong assumption. Various plausible mechanisms have been proposed to get around this problem.

  • An ostrich has feathers and wings, but cannot fly. What is the evolutionary advanage in this? By studying it in its habitat we can determine reasons - but we honestly don't know what dinosaurs ate, not can we watch them eating.

    Long necks can provide several advantages apart from reaching high food sources. First, long necks and tails are used by mammels today as weapons (a giraffe can kill a lion by using its head as a club).

    Second, IIRC during various periods that had long-necked dinosaurs there were few trees and lots of swamp. A long neck would enable the dinosaur to reach foods on marshy ground without having to enter the marshy ground (and potentially become stuck).

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