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Thread: Could a large dinosaur survive today?

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    Could a large dinosaur survive today?

    I don't know if there has been any significant change in oxygen, carbon dioxide, temperature, ultra violet, gravity, speed of light, fine structure constant, cloud cover, water vapour, length of a day, floral carbohydrate etc etc, but if a 200' long 135 ton vegetarian Amphicoelias dinosaur from 100 million years ago was suddenly transported in to a clearing in the middle of today's Brazilian forest, is there any reason why it shouldn't survive, and if not, what would be the likely reason for its demise?

    Last edited by wd40; 2014-Mar-04 at 06:33 PM.

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    Ecotourists

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    I think o2 levels were much higher during the period of large animals. 21% might not be enough to keep them active.

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    Quote Originally Posted by iquestor View Post
    21% might not be enough to keep them active.
    It may even be dipping to 19%
    http://www.i-sis.org.uk/O2DroppingFa...nCO2Rising.php

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    Quote Originally Posted by wd40 View Post
    I don't know if there has been any significant change in oxygen, carbon dioxide, temperature, ultra violet, gravity, speed of light, fine structure constant, cloud cover, water vapour, length of a day, floral carbohydrate etc etc,
    You can look those things up:
    http://en.wikipedia.org/wiki/History_of_the_Earth
    http://en.wikipedia.org/wiki/Atmosph...ird_atmosphere
    http://en.wikipedia.org/wiki/Cretaceous
    http://en.wikipedia.org/wiki/Cretace...ent#Pterosaurs
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    A lower gravity in the past does seem to be a consideration. If so, large dinosaurs could not survive today.

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    Quote Originally Posted by wd40 View Post
    A lower gravity in the past does seem to be a consideration. If so, large dinosaurs could not survive today.
    Expanding Earth is not in consideration by anyone serious.
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    Quote Originally Posted by grapes View Post
    Ecotourists
    Are you not supposed to be a Moderator ?

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    Quote Originally Posted by pzkpfw View Post
    Expanding Earth is not in consideration by anyone serious.
    Not serious ? I did know it already ! But I don't care and like the idea anyway , it make sense to me !

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    Quote Originally Posted by pzkpfw View Post
    Expanding Earth is not in consideration by anyone serious.
    No, this idea is not supported by evidence. Mass does not just come from nowhere, and the amount of mass added to the Earth by meteorites and space dust over its history is minuscule. Not nearly enough to make a measurable difference in gravity, let alone cripple a dinosaur.
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    Quote Originally Posted by wd40 View Post
    A lower gravity in the past does seem to be a consideration. If so, large dinosaurs could not survive today.

    I hardly think that gravity has changed over the ages.
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    Quote Originally Posted by wd40 View Post
    A lower gravity in the past does seem to be a consideration. If so, large dinosaurs could not survive today.
    An infraction was issued for this ATM outside the ATM forum.

    ETA: Yes, just one. Not two infractions. But not a light one since this is not the first time this happens.
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    Here is a fun analysis of how much food (er, people) a T. rex would need to eat to stay alive: http://what-if.xkcd.com/78/

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    AS well as the oxygen percentage being higher, I think the atmospheric pressure was higher also? The denser air meant that the giant flying reptiles could actually fly....

    CO2 was also MUCH higher than today, presumably enabling plants to grow faster and support the grazing of the giant sauropods.

    But I don't know how critical the atmospheric oxygen content was to the survival of a dinosaur. I don't know if it would faint and die due to oxygen lack or simply carry on in a more breathless manner. (The pteradactyls probably would be in trouble however, because they wouldn't get off the ground.)

    You could hypothesise high-altitude adapted dinosaurs, living in the mountains, maybe these would do rather well transported to sea level at present day.

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    The smaller pterosaurs might still fly. The Quetzalcoatlus would almost definitely be grounded.


    EDIT: Maybe not: http://en.wikipedia.org/wiki/Pterosaur_size

    Factors such as the warmer climate of the Mesozoic or higher levels of atmospheric oxygen have been proposed but it's now generally agreed that even the largest pterosaurs could have flown in today's skies. Partially, this is due to the presence of air sacs in their wing membranes [1], as well as the assessment that some pterosaurs may have launched into flight using their front limbs in a quadrupedal stance similarly to bats (birds are bipedal). [2].
    Last edited by Noclevername; 2014-Mar-05 at 01:22 PM.
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    A dinosaur transported to today's Earth would be exposed to possibly life threatening pathogens that didn't exist over 65 million years ago, just as a human may find it difficult to exist in the age of the dinosaurs for similar reasons....gravity would be the least of the worries (none).

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    Quote Originally Posted by kzb View Post
    AS well as the oxygen percentage being higher, I think the atmospheric pressure was higher also? The denser air meant that the giant flying reptiles could actually fly....

    CO2 was also MUCH higher than today, presumably enabling plants to grow faster and support the grazing of the giant sauropods.

    But I don't know how critical the atmospheric oxygen content was to the survival of a dinosaur. I don't know if it would faint and die due to oxygen lack or simply carry on in a more breathless manner. (The pteradactyls probably would be in trouble however, because they wouldn't get off the ground.)

    You could hypothesise high-altitude adapted dinosaurs, living in the mountains, maybe these would do rather well transported to sea level at present day.
    Holocene Earth really sounds a bit decayed.

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    Quote Originally Posted by Spacedude View Post
    A dinosaur transported to today's Earth would be exposed to possibly life threatening pathogens that didn't exist over 65 million years ago, just as a human may find it difficult to exist in the age of the dinosaurs for similar reasons....gravity would be the least of the worries (none).
    But would those pathogens be adapted to attack the animals in question?
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    I'm with Spacedude: A radically different natural environment would be the biggest threat to any dinosaur. It's not just pathogens; plants have had a 100 million years to get better at reproducing and thwarting herbivores, while modern animals (herbivores and predators) would, IMO, swiftly outcompete sauropods despite their enormous size. Sauropods are kind of like Spanish galleons: big, impressive, well-armed, and beautiful to look at, a masterpieces of their time, but still so much kindling in the face of a WW II-era PT boat.

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    But would those pathogens be adapted to attack the animals in question?
    I admit that my profession as a chemist/microscopist does not give me much credibility in the world of microbiology/pathology so my opinion is just an opinion. But it would seem to me that one animal (such as a time traveling dinosaur) would be in a position to be attacked by many different organisms (be it bacterial, fungal, viral, etc) and only one species of either needs to be lethal. Even today's advanced & evolved plant pollens might cause a >65 million YO dinosaur to go into respiratory shock. The Earth of 65 million years ago is Earth-like, but it was not our Earth of today.

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    Quote Originally Posted by Noclevername View Post
    The smaller pterosaurs might still fly. The Quetzalcoatlus would almost definitely be grounded.


    EDIT: Maybe not: http://en.wikipedia.org/wiki/Pterosaur_size
    Interesting problem here. In order for large pterosaurs to fly, you have either got to believe the atmosphere was denser back then, OR to believe they had an average tissue density one quarter that of water.

    It does seem that the arguments for a denser atmosphere stem from the requirement for pterosaurs to fly. But surely there are ways of independently checking the "paleo-pressure" ?

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    I'm no expert, but that wiki article seems to indicate it's a more popular view among paleontologists that the Quetzalcoaltus did indeed fly. If it didn't, it raises the question of what an enormous, ungainly and fragile creature with incredibly long forelimbs that seem very impractical for walking and look suspiciously like supports for wings would even do.

    Edit: And so says Noclevername's second link which I managed to not notice somehow.

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    Quote Originally Posted by Strange View Post
    Here is a fun analysis of how much food (er, people) a T. rex would need to eat to stay alive: http://what-if.xkcd.com/78/
    Oh, I doubt they need 80 Hamburgers. I suspect a T-Rex would want to wash those down with Dr. Pepper. So, it is more like 50 Hamburgers and 40 small Dr. Pepper's.
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    Quote Originally Posted by Romanus View Post
    I'm with Spacedude: A radically different natural environment would be the biggest threat to any dinosaur. It's not just pathogens; plants have had a 100 million years to get better at reproducing and thwarting herbivores, while modern animals (herbivores and predators) would, IMO, swiftly outcompete sauropods despite their enormous size. Sauropods are kind of like Spanish galleons: big, impressive, well-armed, and beautiful to look at, a masterpieces of their time, but still so much kindling in the face of a WW II-era PT boat.
    But dinosaurs had what, 100, 200 million years to evolve before a meteor (or vulcanic eruptions, or both) wiped them out? Mammals were stunted and didn't really "explode" until 65 million years ago. I can see the plant issue though. Didn't flowering plants not exist until the post CT era?

    Would a pack of Utahraptors lose against a pack of lions, hyenas, or wolves? Who would get the better grazing? A herd of triceratops or a herd of bison? Maybe, it'd come down to protection of young: ground-laying dinosaurs with their eggs would not have surviving offspring against mammals, but surely that was an issue even back then, when ovoraptors roamed? Do we know whether all dinosaurs employed R-selection vs K-selection?

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    Quote Originally Posted by Marakai View Post
    But dinosaurs had what, 100, 200 million years to evolve before a meteor (or vulcanic eruptions, or both) wiped them out? Mammals were stunted and didn't really "explode" until 65 million years ago. I can see the plant issue though. Didn't flowering plants not exist until the post CT era?
    Flowering plants existed up to 160 million years ago.

    Would a pack of Utahraptors lose against a pack of lions, hyenas, or wolves?
    Since we don't really know the hunting habits of Utahraptors, no way to tell. We don't even know if they were pack hunters. But the raptors most likely fed on large prey; they couldn't just pop out for a quick rabbit or squirrel the way a hungry canine can.

    Who would get the better grazing? A herd of triceratops or a herd of bison?
    Size isn't everything-- at least when it comes to competing for food. Land that can support a herd of bison could only feed a handful of triceratops at best, the rest would starve. Sometimes the smaller feeders win.

    Maybe, it'd come down to protection of young: ground-laying dinosaurs with their eggs would not have surviving offspring against mammals, but surely that was an issue even back then, when ovoraptors roamed?
    Yes, that's why there are no ground-laying birds today OH WAIT there are.

    Do we know whether all dinosaurs employed R-selection vs K-selection?
    The eggs, nests and female pelvises (pelvi?) we've found all put an upper limit on dinosaur egg laying.
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    Quote Originally Posted by Solfe View Post
    Oh, I doubt they need 80 Hamburgers. I suspect a T-Rex would want to wash those down with Dr. Pepper. So, it is more like 50 Hamburgers and 40 small Dr. Pepper's.
    What a T-Rex eatting frenzy may have looked like.
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    Quote Originally Posted by Elukka View Post
    I'm no expert, but that wiki article seems to indicate it's a more popular view among paleontologists that the Quetzalcoaltus did indeed fly. If it didn't, it raises the question of what an enormous, ungainly and fragile creature with incredibly long forelimbs that seem very impractical for walking and look suspiciously like supports for wings would even do.

    Edit: And so says Noclevername's second link which I managed to not notice somehow.
    Well that's what I'm getting at. It must have flown, but the question is, how?

    From my brief searches, this is the only driver for the theory that the atmosphere was denser back then. But if that is true, there must be other evidence to back it up?

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    New saurus was found...the Torvosaurus..in Portugal this week.

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    Quote Originally Posted by Spacedude View Post
    I admit that my profession as a chemist/microscopist does not give me much credibility in the world of microbiology/pathology so my opinion is just an opinion. But it would seem to me that one animal (such as a time traveling dinosaur) would be in a position to be attacked by many different organisms (be it bacterial, fungal, viral, etc) and only one species of either needs to be lethal. Even today's advanced & evolved plant pollens might cause a >65 million YO dinosaur to go into respiratory shock. The Earth of 65 million years ago is Earth-like, but it was not our Earth of today.
    I know a little although I'm no microbiologist... My guess is it probably wouldn't do the human going back in time much good... but the species barrier is pretty tough to break through for pathogens and certainly the immune system is pretty incredible when it comes to dealing with new threats (it probably doesn't look that way to most people who are having their 3rd summer cold but that's in no small part because we don't see all the times we *don't* develop an active infection despite exposure to an infectious agent) ... zoonotic diseases are relatively rare for a reason and even pathogens that do break the species barrier tend to lose a fair bit of severity in the process, so... they might, or they might not. I don't know anything about dinosaur immune systems though...

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    Quote Originally Posted by wd40 View Post
    When you look at the figures, the decrease in oxygen is very small indeed, and is probably caused by mining rather than any effect caused by the biosphere. That link is a remarkably poor source of information. The biosphere is far too small in mass to affect the oxygen level significantly (in the short to medium term).

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