Difference between revisions of "3042: T. Rex Evolution"

Explain xkcd: It's 'cause you're dumb.
Jump to: navigation, search
(Mention past instance of Extrapolating)
(→‎Explanation)
Line 10: Line 10:
  
 
==Explanation==
 
==Explanation==
−
{{incomplete|Created by a BOT WITH NEGATIVE LIMBS - fact-check the graph's "early" claim and flesh things out a bit. Do NOT delete this tag too soon.}}
+
{{incomplete|Created by a BOT WITH NEGATIVE LIMBS, CURRENTLY LIVING IN LOCH NESS - fact-check the graph's "early" claim and flesh things out a bit. Do NOT delete this tag too soon.}}
  
 
The small and seemingly useless forelimbs of ''Tyrannosaurus rex'' have often been used as a source of humour in works of fiction that feature dinosaurs. Randall claims that the ancestors of ''T. Rex'' had (relatively) longer and therefore more useful forelimbs, and hypothesizes that - had non-avian dinosaurs not suffered an extinction event - this trend of "reduced limbs" would continue until present-day descendants of ''T. Rex'' were limbless creatures not unlike a giant snake.
 
The small and seemingly useless forelimbs of ''Tyrannosaurus rex'' have often been used as a source of humour in works of fiction that feature dinosaurs. Randall claims that the ancestors of ''T. Rex'' had (relatively) longer and therefore more useful forelimbs, and hypothesizes that - had non-avian dinosaurs not suffered an extinction event - this trend of "reduced limbs" would continue until present-day descendants of ''T. Rex'' were limbless creatures not unlike a giant snake.
  
−
In reality, while animals do lose usage of their limbs - such as the hind legs of a whale - the development of these vestigial limbs would not apply to other limbs. A T. rex would continue to have substantial need for its hind legs, which it used for running and chasing prey, and would have no reason to lose legs unless environmental factors favored a limbless lifestyle. This has happened multiple times in the Order Squamata, the lizards and snakes, where limbless body plans have evolved convergently over and over such as in blind worms as compared to true snakes. However these circumstances that encourage such lifestyles are not likely to happen to the large predatorial Tyrannosaurus. With that said Tyrannosaurus would likely eventually lose its arms altogether if it never went extinct.
+
Evolutionary theory indicates that different selection pressures cause the development or loss of characteristics, as those characteristics which enable better survival to continuation of the species are emphasised and those which don't (such as wasting nutrients on growing unnecessary limbs) are not.
 +
 
 +
In reality, while animals have evolved to lose usage of the limbs of their predecessors - such as the hind legs of a whale - the development of these vestigial limbs would not apply to other limbs. A T. rex would continue to have substantial need for its hind legs, which it used for running and chasing prey, and would have no reason to lose legs unless environmental factors favored a limbless lifestyle. This has happened multiple times in the Order Squamata, the lizards and snakes, where limbless body plans have evolved convergently over and over such as in blind worms as compared to true snakes. However these circumstances that encourage such lifestyles are not likely to happen to the large predatorial Tyrannosaurus. With that said Tyrannosaurus would likely eventually lose its arms altogether if it never went extinct.
  
 
The title text claims that as ''T. Rex'' was also larger than its ancestors, the same trend in growth would continue such that the hypothetical limbless present-day descendant would be even larger than the [https://what-if.xkcd.com/78/ famously elephant-sized] ''T. Rex''. In reality animals do not linearly grow in size and a modern Tyrannosaurus would not necessarily be dramatically larger, and could easily have gotten somewhat smaller even with the same body plans and lifestyle.
 
The title text claims that as ''T. Rex'' was also larger than its ancestors, the same trend in growth would continue such that the hypothetical limbless present-day descendant would be even larger than the [https://what-if.xkcd.com/78/ famously elephant-sized] ''T. Rex''. In reality animals do not linearly grow in size and a modern Tyrannosaurus would not necessarily be dramatically larger, and could easily have gotten somewhat smaller even with the same body plans and lifestyle.

Revision as of 09:45, 25 January 2025

T. Rex Evolution
Unfortunately, body size and bite force continue to increase.
Title text: Unfortunately, body size and bite force continue to increase.

    Explanation

    Ambox warning blue construction.svg This is one of 52 incomplete explanations:
    Created by a BOT WITH NEGATIVE LIMBS, CURRENTLY LIVING IN LOCH NESS - fact-check the graph's "early" claim and flesh things out a bit. Do NOT delete this tag too soon. If you can fix this issue, edit the page!

    The small and seemingly useless forelimbs of Tyrannosaurus rex have often been used as a source of humour in works of fiction that feature dinosaurs. Randall claims that the ancestors of T. Rex had (relatively) longer and therefore more useful forelimbs, and hypothesizes that - had non-avian dinosaurs not suffered an extinction event - this trend of "reduced limbs" would continue until present-day descendants of T. Rex were limbless creatures not unlike a giant snake.

    Evolutionary theory indicates that different selection pressures cause the development or loss of characteristics, as those characteristics which enable better survival to continuation of the species are emphasised and those which don't (such as wasting nutrients on growing unnecessary limbs) are not.

    In reality, while animals have evolved to lose usage of the limbs of their predecessors - such as the hind legs of a whale - the development of these vestigial limbs would not apply to other limbs. A T. rex would continue to have substantial need for its hind legs, which it used for running and chasing prey, and would have no reason to lose legs unless environmental factors favored a limbless lifestyle. This has happened multiple times in the Order Squamata, the lizards and snakes, where limbless body plans have evolved convergently over and over such as in blind worms as compared to true snakes. However these circumstances that encourage such lifestyles are not likely to happen to the large predatorial Tyrannosaurus. With that said Tyrannosaurus would likely eventually lose its arms altogether if it never went extinct.

    The title text claims that as T. Rex was also larger than its ancestors, the same trend in growth would continue such that the hypothetical limbless present-day descendant would be even larger than the famously elephant-sized T. Rex. In reality animals do not linearly grow in size and a modern Tyrannosaurus would not necessarily be dramatically larger, and could easily have gotten somewhat smaller even with the same body plans and lifestyle.

    This comic may be tangentially related to the fact that birds are dinosaurs that survived the KT extinction, which is a recurring theme on xkcd.

    Extrapolation was previously mentioned in comic 605: Extrapolating.

    Transcript

    Ambox warning green construction.svg This is one of 27 incomplete transcripts:
    Do NOT delete this tag too soon. If you can fix this issue, edit the page!
    [A graph of limbs over time, with 3 animals represented]
    [The vertical axis is labelled Limbs, from 0 to 4]
    [The horizontal axis is not labelled but represents time, in ticks of 10 million years, from 180 million years ago to 0.]
    ["Extinction" points to 65 million years ago, and "Now" points to 0.]
    [The first animal, a regular dinosaur, is in the top left: 4 limbs, 150 million years ago.]
    4 normal limbs
    [An arrow goes from it to the second animal, a T. Rex, in the middle, just left of "extinction".]
    Barely more than 2
    [A dashed arrow with a question mark goes from it to the last animal: a leg-less dinosaur with a big mouth.]
    ???
    [Caption below the panel:]
    If T. Rex hadn't gone extinct
    (Linear extrapolation)

    comment.png  Add comment      new topic.png  Create topic (use sparingly)     refresh discuss.png  Refresh 

    Discussion

    too soon bro 😭😭😭😭 Caliban (talk) 12:49, 24 January 2025 (UTC)

    The next stage in T-Rex would be a massive lizard with incredible bite force and barely any limbs... an Alligator 172.70.115.198 13:31, 24 January 2025 (UTC)

    Well, we do have large, legless animals with big mouths and teeth ... they're called 'snakes'. 172.70.178.44 15:25, 24 January 2025 (UTC)
    two enter keys to form a new line Caliban (talk) 13:33, 24 January 2025 (UTC)

    So that explains the loch ness monster? 172.70.250.195 14:47, 24 January 2025 (UTC)

    Probably not. T. Rex lived in America. --Coconut Galaxy (talk) 14:50, 24 January 2025 (UTC)
    Since when has obvious contradictory facts gotten in the way of cryptids? 108.162.238.104 15:04, 24 January 2025 (UTC)
    Not another CG account sigh 42.book.addictTalk to me! 16:02, 24 January 2025 (UTC)
    alright, calm down, it's just the person(s?) who tried to start a conscript ARG on this wiki IIRC Caliban (talk) 17:14, 24 January 2025 (UTC)
    I guess you’re right. I should probably follow WP:GOODFAITH more when it comes to matters like this 42.book.addictTalk to me! 17:47, 24 January 2025 (UTC)
    This tyrannosaurus wouldn't be the last american to come to Scotland and terrorise the locals. Kev (talk) 09:47, 25 January 2025 (UTC)
    My account name is randomly generated 🤷‍♂️ --Coconut Galaxy (talk) 08:07, 25 January 2025 (UTC)

    So this is where snakes come from! -- Petercordia (talk) 17:01, 24 January 2025 (UTC) (please sign your comments with ~~~~)

    Looks like this is how the tsuchinoko came to be... TheGoomba98 (talk) 17:12, 24 January 2025 (UTC)

    Do we have any figures on just how strong the bite force would be? 172.68.22.223 17:15, 24 January 2025 (UTC)

    Strangely, those studying this have never returned any results.172.70.162.126 09:34, 27 January 2025 (UTC)

    It seems like many here say that the T-Rex would become a snake, but it would have to simultaneously evolve to be able to move via the scales on its stomach, so I don't think it's guaranteed Sophon (talk) 18:45, 24 January 2025 (UTC)

    You're right. It'll become a huge slug. 172.68.205.178 20:31, 24 January 2025 (UTC)

    Isn't this how whales evolved? Of course, they lost their hind limbs first, while T Rex was losing its forelimbs.Vfp15 (talk) 23:21, 24 January 2025 (UTC)

    Dolphins too? I remember finding a snake once with tiny non-functional legs. Surely there are some cool pics on Commons for this explanation, anyone? 162.158.91.48 02:24, 25 January 2025 (UTC)
    Cetaceans (whales, dolphins, and porpoises) evolved from an anccestral land species whose modern descendants include deer, cattle, hippos, and giraffes. Hippos are thought to be the closest relatives. Barmar (talk) 18:05, 25 January 2025 (UTC)
    I was pretty sure that because of the bone structure, it was thought that that the rear legs merged into the flipper, and that's why it's horizontal, versus vertical like in a fish. At least that's what I thought I read once. Looking at it now, it seems it does have some semblance of a vestigial hip / rear limbs and the fluke is just cartilage. Although seals and walruses do seem to have developed in the way I thought. As for the T. Rex, it actually turned into a Drinking bird. SammyChips (talk) 17:15, 27 January 2025 (UTC)
          comment.png  Add comment
    Retrieved from "https://www.explainxkcd.com/wiki/index.php?title=3042:_T._Rex_Evolution&oldid=363517"