the human species everchanging tail

Iron Maiden

Iron Maiden

Paragon of Bacon
Orange Room Supporter
So apparently to be able to walk in a the bipedal way we do today, our ancestors joined up and decided tails are not cool any more... talk about being cheated


How Humans Lost Their Tail, Twice

You started off your life with a tail, but now just have a tailbone. This is why that happened.

Humans can't seem to keep a tail, suggests new research that finds our early ancestors lost tails not just once, but twice.

The findings, published in the journal Current Biology, not only help explain why people don't wag dog-like tails, but they also shed light on why we all have a tailbone and begin life with an actual tail that gradually disappears.

"Fleshy tails go all the way back to the earliest vertebrate ancestors and are found in very young embryos, so it would be very difficult to get rid of them entirely without causing other problems," author Lauren Sallan told Seeker. "As a result, both fishes and humans have had to stunt growth instead, leaving a buried, vestigial tail much like the legs of whales."

The origins of this mysterious vestigial tail go back to fish. For the study, Sallan, an assistant professor in the University of Pennsylvania's Department of Earth and Environmental Science, analyzed 350-million-year-old hatchlings of the fossil fish Aetheretmon. This jawed fish distant ancestor of terrestrial animals today had both a scaly, fleshy tail and a flexible tail fin, sitting one atop the other.

Sallan found these structures were entirely separate. By comparing the Aetheretmon hatchlings with those of living fish, she found that the two "tails" started out one atop the other and then grew on their own. This discovery overturns at least two centuries of scientific belief that the modern adult fish tail fin was simply added to the end of an ancestral tail shared with land animals.



Illustration: The early double-tailed fish Aetheretmon swimming alongside a singled-tailed modern pufferfish and an early tetrapod in a 350-million-year old river. Credit: John Megahan
The disconnect means that the two tails went on their own evolutionary paths. Fish lost the fleshy tail and kept the flexible one to improve their swimming. Having just the back fin, she explained, "allows for more refined movements, which a muscular tail (originally present for power swimming) would disrupt."

Fish that evolved to become semi-aquatic and then land-dwelling animals lost the flexible back fin, but kept the fleshier one that over time became the familiar appendage we now see on dogs, cats, cows and many other animals. As dogs show, tails are useful for visual communication, slapping away flying insects and other functions.

Adult apes, including human ancestors, took the tail loss process a step further, Sallan said, "losing the remaining bony tail for better upright movement. Like fish, the remnants of an embryonic bony tail are buried in our lower backs—the coccyx or tailbone—stunted by a loss of molecular signals that would otherwise cause it to grow out like an arm or leg. Thus, humans and fish embryos share mechanisms for controlling tail form."

The fossil record for early apes is not great, but since apes lack tails, she thinks our primate ancestors lost them when they first started to walk on two legs. Monkeys that often walk this way have stunted tails, further proving that tails can get in the way of moving around while upright.

So in the end my grandpa was somehow right when he used to say: "El room damoun azra2 w 3andoun danab" :)
 
  • Advertisement
  • Abou Sandal

    Abou Sandal

    Legendary Member
    Orange Room Supporter
    "The fossil record for early apes is not great, but since apes lack tails, she thinks our primate ancestors lost them when they first started to walk on two legs"

    Yeah well...Another nice story anyway.
     
    Manifesto

    Manifesto

    Legendary Member
    Orange Room Supporter
    "The fossil record for early apes is not great, but since apes lack tails, she thinks our primate ancestors lost them when they first started to walk on two legs"

    Yeah well...Another nice story anyway.
    I smell sarcasm. Are you a believer in creationism, Abou Sandal?
     
    Abou Sandal

    Abou Sandal

    Legendary Member
    Orange Room Supporter
    I'm shocked to say the least. You sound smarter than that.
    If you dig deeper you might understand better. (ps: There is a thread for that matter that you could consult as a start)
     
    J

    joseph_lubnan

    Legendary Member
    So apparently to be able to walk in a the bipedal way we do today, our ancestors joined up and decided tails are not cool any more... talk about being cheated


    How Humans Lost Their Tail, Twice

    You started off your life with a tail, but now just have a tailbone. This is why that happened.

    Humans can't seem to keep a tail, suggests new research that finds our early ancestors lost tails not just once, but twice.

    The findings, published in the journal Current Biology, not only help explain why people don't wag dog-like tails, but they also shed light on why we all have a tailbone and begin life with an actual tail that gradually disappears.

    "Fleshy tails go all the way back to the earliest vertebrate ancestors and are found in very young embryos, so it would be very difficult to get rid of them entirely without causing other problems," author Lauren Sallan told Seeker. "As a result, both fishes and humans have had to stunt growth instead, leaving a buried, vestigial tail much like the legs of whales."

    The origins of this mysterious vestigial tail go back to fish. For the study, Sallan, an assistant professor in the University of Pennsylvania's Department of Earth and Environmental Science, analyzed 350-million-year-old hatchlings of the fossil fish Aetheretmon. This jawed fish distant ancestor of terrestrial animals today had both a scaly, fleshy tail and a flexible tail fin, sitting one atop the other.

    Sallan found these structures were entirely separate. By comparing the Aetheretmon hatchlings with those of living fish, she found that the two "tails" started out one atop the other and then grew on their own. This discovery overturns at least two centuries of scientific belief that the modern adult fish tail fin was simply added to the end of an ancestral tail shared with land animals.



    Illustration: The early double-tailed fish Aetheretmon swimming alongside a singled-tailed modern pufferfish and an early tetrapod in a 350-million-year old river. Credit: John Megahan
    The disconnect means that the two tails went on their own evolutionary paths. Fish lost the fleshy tail and kept the flexible one to improve their swimming. Having just the back fin, she explained, "allows for more refined movements, which a muscular tail (originally present for power swimming) would disrupt."

    Fish that evolved to become semi-aquatic and then land-dwelling animals lost the flexible back fin, but kept the fleshier one that over time became the familiar appendage we now see on dogs, cats, cows and many other animals. As dogs show, tails are useful for visual communication, slapping away flying insects and other functions.

    Adult apes, including human ancestors, took the tail loss process a step further, Sallan said, "losing the remaining bony tail for better upright movement. Like fish, the remnants of an embryonic bony tail are buried in our lower backs—the coccyx or tailbone—stunted by a loss of molecular signals that would otherwise cause it to grow out like an arm or leg. Thus, humans and fish embryos share mechanisms for controlling tail form."

    The fossil record for early apes is not great, but since apes lack tails, she thinks our primate ancestors lost them when they first started to walk on two legs. Monkeys that often walk this way have stunted tails, further proving that tails can get in the way of moving around while upright.

    So in the end my grandpa was somehow right when he used to say: "El room damoun azra2 w 3andoun danab" :)
    I do not evolve :)
     
    Iron Maiden

    Iron Maiden

    Paragon of Bacon
    Orange Room Supporter
    "The fossil record for early apes is not great, but since apes lack tails, she thinks our primate ancestors lost them when they first started to walk on two legs"

    Yeah well...Another nice story anyway.
    Whats the problem here exactly?
     
    Abou Sandal

    Abou Sandal

    Legendary Member
    Orange Room Supporter
    Whats the problem here exactly?
    She "thinks"... based on her beliefs in the theory of evolution...Meaning it's just some idea, based on some theory...Just a story in my understanding. Nice and entertaining, but story nevertheless. I have no problem with that, actually.
     
    X

    Xynus87

    New Member
    Common descent can be ultimately proved by population genetics, all men and women trace their ancestry to Y-chromosomal Adam and mitochondrial Eve (respectively). However, these two individuals might not have necessarily lived together, y-chromosomal Adam should have lived approximately circa 161,300 years before present, meanwhile mtDNA Eve closely at 150,000 years before present. Did they live together? We don't know. Also I don't think Evolution necessarily neglects religious beliefs as long as the latter doesn't try to explain "creation" in a sense of detailed description that defies scientific evidence, after all, science is in constant change.

    Even as someone who believes in evolution and abiogenesis, we still lack massive evidence as to confirm the Darwinian thesis which is aimed at explaining the evolution of beings from one specie to another e.g: The evolution of whales from a horse-like being to a sea creature. Meanwhile this hypothesis is aimed to explain the fact that whales give birth and don't lay eggs like most vertebrates which are ovoviviparous. Whales are not special, there are multiple mammals that actually lay eggs instead of of regular "mammalian" birth like platypus (which are monotremes i.e primitive mammals). Still, most of these explanations are mere hypotheses as to what we have/have been observing in the adaptation of living creatures. So till we have enough evidence, I don't think we can solidly claim the theory as absolute truth, and remember, absence of evidence is not evidence of absence. This goes for both God and for the former. And to add more, as the others noted "She thinks" and this shows that this is not absolute truth rather a feasible "temporarily" explanation of what this "evolutionary biologist" seeks to be true.
     
    Abou Sandal

    Abou Sandal

    Legendary Member
    Orange Room Supporter
    The thing is, that for years, we have been served stories such as the one above, by "scientists" who are more Darwinian than Darwin himself. They just take a fossil from here or there, and make it tell a story, different than the one it has to tell. Has Darwin been alive today, I believe he would have already dismissed his original theory, at least in light of the fossil record discovered since his time till now, which only adds to his own original doubts. And I have no doubt that many today's "believers" would then jump to discredit him, if he did so.

    Mutation process, genetics, adaptation process, mathematics, fossil record, the Cambrian explosion...All say a much different story than that of the theory of evolution, when not precisely the opposite.

    Yet that theory is presented to us and taught to our children as an absolute and proven truth. Something is fishy here....*pun intended*



    The Fossil Record: Proof of Noah's Flood or Evolution
     
    X

    Xynus87

    New Member
    The thing is ....
    Agreed, and I mentioned this in my above post. It's definitely a downside that we don't have much fossils that can ultimately prove whatever hypothesis we have deemed as the best to explain our theories. However, absence of evidence is not evidence of absence. It's still quite suspicious of them, for example many fossils I have seen from the village of "Haqel" which houses fossils of fishes and shrimps, apparently they are still the same even though the fossils themeselves date to the Jurassic period. For example, the octopus fossil found was deemed similar to the current one, even though it's ~95 million years old:

    This provides important evolutionary information. The more primitive relatives of octopuses had fleshy fins along their bodies. The new fossils are so well preserved that they show, like living octopus, that they didn't have these structures.

    And although there is a certain difference (more phenotypical than evolutionary) like having "Fleshy fins" this only corresponds to micro-evolution which is the ability for beings to adapt to their surroundings and environment and this certainly can be seen within humans, e.g: cold-adapted humans and warm-adapted humans etc..

    In addition, they found a special "Lizard-like" specie that they classified as close to snakes called Aphanizocnemus libanensis:

    Another find was a snake with two legs. This provided a valuable example of evolution at work, illustrating how ancient lizards became modern snakes.

    However the thing we're missing is the evidence of the intermediate evolution i.e fossils that can be used to illustrate macro-evolution at work.
     
    Last edited:
    Abou Sandal

    Abou Sandal

    Legendary Member
    Orange Room Supporter
    Agreed, and I mentioned this in my above post. It's definitely a downside that we don't have much fossils that can ultimately prove whatever hypothesis we have deemed as the best to explain our theories. However, absence of evidence is not evidence of absence. It's still quite suspicious of them, for example many fossils I have seen from the village of "Haqel" which houses fossils of fishes and shrimps, apparently they are still the same even though the fossils themeselves date to the Jurassic period. For example, the octopus fossil found was deemed similar to the current one, even though it's ~95 million years old:

    This provides important evolutionary information. The more primitive relatives of octopuses had fleshy fins along their bodies. The new fossils are so well preserved that they show, like living octopus, that they didn't have these structures.

    And although there is a certain difference (more phenotypical than evolutionary) like having "Fleshy fins" this only corresponds to micro-evolution which is the ability for beings to adapt to their surroundings and environment and this certainly can be seen within humans, e.g: cold-adapted humans and warm-adapted humans etc..
    And maybe that is not even a "micro-evolution", but just a variety. One of hundreds within the same specie. Also, it is extremely important to differentiate between adaptation and evolution. And I'm not even talking about the false and abusive use of the word "mutation". (Which is a rather abnormal and non-viable transformation, that has nothing in it related to the X-men)

    Also an important thing to point out at, is that although every individual fossil can tell a multitude of stories, still, there is yet one story that fossils never told. It's evolution/transformation from one specie to others. Quite the opposite, judging by the Cambrian explosion fossils, and by the fact that many fossils are discovered fossilized right next to the same species they are supposedly issued from through a supposed evolution.

    This alone dismisses the whole theory. And Darwin knew that and acknowledged it, however he hoped that future discoveries might prove otherwise. But then, new discoveries kept showing that the theory is not sustainable, however, they were systematically overshadowed by a plethora of stories, that prove only one form of evolution, which is the one related to the imagination of those laying them down.
     
    Dynamite Joe

    Dynamite Joe

    Well-Known Member
    It's psuedoscience. First, the Cambrian explosion happened over millions of years which is enough for evolution to act. Secondly, evolution is not characterised by a clean gradual growth, but punctuated by periods of major explosions and diversification of new species and extinctions. Thirdly, environmental changes can trigger sudden changes to occur (to reiterate sudden does not mean hundreds or thousands of years, but measure in millions...) Likely a combination of causes such as runaway glaciation, increase of atmospheric oxygen, changes in the seafloor, and other culprits led to the Cambrian explosion. No matter, these are lot more convincing than old Jehovah creating Trilobites..
     
    Abou Sandal

    Abou Sandal

    Legendary Member
    Orange Room Supporter
    It's psuedoscience. First, the Cambrian explosion happened over millions of years which is enough for evolution to act. Secondly, evolution is not characterised by a clean gradual growth, but punctuated by periods of major explosions and diversification of new species and extinctions. Thirdly, environmental changes can trigger sudden changes to occur (to reiterate sudden does not mean hundreds or thousands of years, but measure in millions...) Likely a combination of causes such as runaway glaciation, increase of atmospheric oxygen, changes in the seafloor, and other culprits led to the Cambrian explosion. No matter, these are lot more convincing than old Jehovah creating Trilobites..
    The Cambrian explosion shows that all species we know, suddenly appeared altogether out of nowhere. No transition, no transformation, no nothing related to Darwin's theory of evolution.

    And there is nothing from the pre-Cambrian era that shows anything related to gradual transformation from one specie to another, let alone to multitude of others.

    ‘To the question of why we do not find rich fossiliferous deposits belonging to these…periods prior to the Cambrian system, I can give no satisfactory answer’

    Charles Darwin.

    Darwin was well aware and puzzled by the fact that the fossil record contradicted what his theory of evolution predicted. And that was his dilemma.

    He hoped that some day such record would be discovered, but nothing.
    Nothing but tales and video animations, trying to push hard for at least some hint of proof, by making few fossils from here and there tell stories different from the ones they say...And yet, that theory is taught to children as an absolute proof.
     
    Dynamite Joe

    Dynamite Joe

    Well-Known Member
    The Cambrian explosion shows that all species we know, suddenly appeared altogether out of nowhere. No transition, no transformation, no nothing related to Darwin's theory of evolution.

    And there is nothing from the pre-Cambrian era that shows anything related to gradual transformation from one specie to another, let alone to multitude of others.

    ‘To the question of why we do not find rich fossiliferous deposits belonging to these…periods prior to the Cambrian system, I can give no satisfactory answer’

    Charles Darwin.

    Darwin was well aware and puzzled by the fact that the fossil record contradicted what his theory of evolution predicted. And that was his dilemma.

    He hoped that some day such record would be discovered, but nothing.
    Nothing but tales and video animations, trying to push hard for at least some hint of proof, by making few fossils from here and there tell stories different from the ones they say...And yet, that theory is taught to children as an absolute proof.
    Not only is it an inaccurate statement to say Cambrian organisms suddenly appeared out of nowhere, but absurd. The Cambrian explosion simply means there was a rapid appearance of fossils in the strata of that period comparatively to Precambrian. Keep in mind, the Cambrian explosion itself lasted about 25 million years, which is a very long time and far from sudden.

    Aside from that, Precambrian creatures did not fossilise well, so it's not surprising the fossil record is thin comparatively to the Cambrian era.

    Furthemore, evolution is not a theory but a scientific fact. It does not rely exclusively on the fossil evidence and comparative anatomy as in Darwin's time. Moreover, gene sequencing and comparative chemistry has revolutionised the study of evolution and provides solid evidence of common descent.

    Lastly, misconceptions about evolution lead people to make erroneous conclusions, which you have made yourself. That the gap in the fossil record disproves evolution, that evolution is organisms adapting to their environment, that humans descend from monkeys/apes as opposed to sharing common ancestry, or that evolution is linear rather than a branching process, and so on...
     
    Top