Being quadrapedial is more stable than being bipedial, so wouldn't it make more sense for humans to have tails than other creatures? Our ape/man common ancestor must have lost it, but souldn't it have reappered if it would make apes more balanced? Why do quadrapedial cretures still have a tail?
Evolution III
- Thread starter Enigma'07
- Start date
Some things that would make sense in a project of a living being do not occur because living beings are not projects, but results of evolution. We also could thing that would be good to we be able to change our skin color like chameleons, so it should have appeared, but that just isn't the way that evolution works.
But about that specific problem... human ancestors at some time were used to not have tails, maybe tails disappeared because they are a disvantage, maybe because their bodies were becoming bigger during evolution, and tails could not work as prehensile members anymore, being just a unuseful member propense to harm in accidents; plus, having smaller tails would make them more agile. So during the generations, tails "shrank" till disappear. At this point, these beings are perfectly adapted, used to, not have tails. A tail would be a huge trouble, they simply would not know how to use that. Besides it, a tail would not ressurect entire and functional, but as a "atrophied" atavic tail, that probably doesn't carry any advantage that a functional tail have, for equilibrium and etc. In fact, is just a easy to harm unuseful appendix.
Not all quadrupedal animails have tails, for example, quadrupedal apes haven't, and horse's tails are almost meaningless compared with their body size (they look bigger because all of that fur, but above it, they're really tiny). The general answer to why any animal have a tail would be that's because it were not selected against, and can vary a lot specifically. Eventually it's target of stabilizing pressure, or pressure to conserve as it's right now. For example, cheetah's tails are thought to work as a gyroscope for balance in their hunt; variations with smaller or bigger tails in proportion with their body would be less efficient hunters. In animals were tails do not have this equilibrium use, such as lions (i guess), dogs, horses, etc, it may be a important signal of expression of mood. In peacocks it's sexually atractive. In crocodiles, that's indispensable to swimming.
But about that specific problem... human ancestors at some time were used to not have tails, maybe tails disappeared because they are a disvantage, maybe because their bodies were becoming bigger during evolution, and tails could not work as prehensile members anymore, being just a unuseful member propense to harm in accidents; plus, having smaller tails would make them more agile. So during the generations, tails "shrank" till disappear. At this point, these beings are perfectly adapted, used to, not have tails. A tail would be a huge trouble, they simply would not know how to use that. Besides it, a tail would not ressurect entire and functional, but as a "atrophied" atavic tail, that probably doesn't carry any advantage that a functional tail have, for equilibrium and etc. In fact, is just a easy to harm unuseful appendix.
Not all quadrupedal animails have tails, for example, quadrupedal apes haven't, and horse's tails are almost meaningless compared with their body size (they look bigger because all of that fur, but above it, they're really tiny). The general answer to why any animal have a tail would be that's because it were not selected against, and can vary a lot specifically. Eventually it's target of stabilizing pressure, or pressure to conserve as it's right now. For example, cheetah's tails are thought to work as a gyroscope for balance in their hunt; variations with smaller or bigger tails in proportion with their body would be less efficient hunters. In animals were tails do not have this equilibrium use, such as lions (i guess), dogs, horses, etc, it may be a important signal of expression of mood. In peacocks it's sexually atractive. In crocodiles, that's indispensable to swimming.
if an animal didnt get off two of its legs, it would never have the chance to use its free legs (hands) for intelligent opertations, and thus he would not evolve into intelligent species able to wield tools and think.
unless of course, Aliens grabbed said quadrapedial animal and forced it to be somewhat smart (genetics)
unless of course, Aliens grabbed said quadrapedial animal and forced it to be somewhat smart (genetics)
But you're inverting a bit the causes and consequences. Humans didn't evolved to bipedalism with the target of set free their hands to make tools. They were pratically bipedals at the time they moved from a more terrestrial locomotion; they had a gibbon/orangutan basic morphology, that is bipedal when in the ground. They had no pressure to evolve to quadrupedalism, so they remained bipeds, and so, could use their hands to make tools, more than primarily quadrupedal apes.zonabi said:
Probably is that, I don't know each case specifically, but makes sense. If it keeps them free of some parasites, is likely to be conserved by natural selection. But yet, some traits can be unuseful and remain conserved solely because aren't selected against, and also the absence of the trait isn't positively selected.Enigma'07 said:
Enigma'07 said:
Who says? Define "stable". For the type of existence they lead, humans are prefectly "stable" as bipeds. The whole premise of this thread is faulty, or at best, anthropomorphic.
The question "Why do organisms display adaptions?" is not answered by "to survive" but by "Because those who have not adapted, have not survived"