4 ms·

Thank you, that is the best just-so story I've read in a long while! If the subtext is not apparent: https://en.m.wikipedia.org/wiki/Just-so_story https://en.m

by lolc 2y ago

Thank you, that is the best just-so story I've read in a long while! If the subtext is not apparent: https://en.m.wikipedia.org/wiki/Just-so_story https://en.m.wikipedia.org/wiki/Just-so_story

emporas 2y ago
Even if the distance of the right hand to the heart (on the left) is just 10% more than if it was located on the right side, that small difference for 50 million years might be significant enough for a right hand trait to be established in the population. Any scientist who wants to verify this hypothesis (or the-just-so story) is welcomed, and this explanation might be upgraded to totally valid scientific theory or serve as a warning to the general public about unproven scientific falsehoods.
- HarHarVeryFunny 2y ago
  We've got veins returning blood to the heart on both sides of our body, and it all has to go via the circulatory system - not as-the-crow-flies from any point directly to the heart. In any case, even if there was (seems not) a few seconds delay in terms of how quickly poison from a snake bite on one side of body vs other got to the heart, that's not going to make any difference to survivability. It seems that developmental asymmetry, resulting in (fairly major) left vs right brain functional differences, is what has lead to left vs right handedness.
  - emporas 2y ago
    I would say that brain asymmetry probably is not the cause of hand and leg asymmetry. It has to do either with venomous [1] plants and animals or with muscle use and fatigue. When the hand is stung or burned it performs a quick centrifugal movement instinctively. Then many mammals can suck some blood out with their mouths. That minimizes the venom in circulation, and some additional time to get to the heart might be less damaging, especially when the venom is not very plentiful like bees, scorpions etc. When the venom is of a big quantity, like big snakes then probably it doesn't make a difference. One other factor is muscle isolation and helping the heart to not get tired from work. Considering that the whole point of gyms is muscle isolation, which is very difficult to achieve normally, a human or monkey cracking nuts or cracking bones for hours, it will tire the left side (where the heart is located) much more increase palpitations, and consequently the risk for heart attack. That last one could be tested, working more using the left hand -> increase palpitations or not. As a counter example, the chimp when it cracks the turtle, it works with both hands [2]. [1] Venomous not poisonous i misspoke previously. [2] https://www.youtube.com/watch?v=o7dRvX2f9Rs https://www.youtube.com/watch?v=o7dRvX2f9Rs
    - HarHarVeryFunny 2y ago
      Your reasoning makes no sense. Using your left hand to crack nuts vs your right hand makes no difference as far as your heart is concerned. If you are working hard enough to increase your metabolic rate, then your heart will be pumping faster in either case. Also, your theory that increased exercise leads to heart attacks is the opposite of reality!
      - emporas 2y ago
        Exercise prevents heart attacks when you have excessive calories, you get adequate sleep and do not sleep outside in the winter, you have a dry place to stand and are not out in the rain and so on. Exercise leads to muscle loss when the fat reserves are depleted and calorie intake is limited. Anyway there are ways to falsify or verify that hypothesis, but it needs some resources, not much but still, it needs time and subjects to test the hypothesis on. So for the foreseeable future, it will stay as it is, a hypothesis.
        HarHarVeryFunny 2y ago
        If your hypothesis was true, then it'd be glaringly obvious, because there'd be a high correlation between left handedness and increased lifespan.
- lolc 2y ago
  In your logic obviously the majority of people must be left handed because the left arm being closer to the heart means higher blood flow and thus better stamina. Oh but why isn't it so? Because of venom? Let's set our scientists on that. No wait I got one: Attacking prey is easier with the sun in the back so the hunters would often return from the north. The right handed ones would show better muscle tone in the setting sun and we know women select for muscle mass! Sexual selection baby! Way better story I'm sure you agree. Scientists gotta switch.

by lolc 2y ago

Thank you, that is the best just-so story I've read in a long while! If the subtext is not apparent: https://en.m.wikipedia.org/wiki/Just-so_story https://en.m.wikipedia.org/wiki/Just-so_story

emporas 2y ago

Even if the distance of the right hand to the heart (on the left) is just 10% more than if it was located on the right side, that small difference for 50 million years might be significant enough for a right hand trait to be established in the population. Any scientist who wants to verify this hypothesis (or the-just-so story) is welcomed, and this explanation might be upgraded to totally valid scientific theory or serve as a warning to the general public about unproven scientific falsehoods.

HarHarVeryFunny 2y ago
We've got veins returning blood to the heart on both sides of our body, and it all has to go via the circulatory system - not as-the-crow-flies from any point directly to the heart. In any case, even if there was (seems not) a few seconds delay in terms of how quickly poison from a snake bite on one side of body vs other got to the heart, that's not going to make any difference to survivability. It seems that developmental asymmetry, resulting in (fairly major) left vs right brain functional differences, is what has lead to left vs right handedness.
- emporas 2y ago
  I would say that brain asymmetry probably is not the cause of hand and leg asymmetry. It has to do either with venomous [1] plants and animals or with muscle use and fatigue. When the hand is stung or burned it performs a quick centrifugal movement instinctively. Then many mammals can suck some blood out with their mouths. That minimizes the venom in circulation, and some additional time to get to the heart might be less damaging, especially when the venom is not very plentiful like bees, scorpions etc. When the venom is of a big quantity, like big snakes then probably it doesn't make a difference. One other factor is muscle isolation and helping the heart to not get tired from work. Considering that the whole point of gyms is muscle isolation, which is very difficult to achieve normally, a human or monkey cracking nuts or cracking bones for hours, it will tire the left side (where the heart is located) much more increase palpitations, and consequently the risk for heart attack. That last one could be tested, working more using the left hand -> increase palpitations or not. As a counter example, the chimp when it cracks the turtle, it works with both hands [2]. [1] Venomous not poisonous i misspoke previously. [2] https://www.youtube.com/watch?v=o7dRvX2f9Rs https://www.youtube.com/watch?v=o7dRvX2f9Rs
  - HarHarVeryFunny 2y ago
    Your reasoning makes no sense. Using your left hand to crack nuts vs your right hand makes no difference as far as your heart is concerned. If you are working hard enough to increase your metabolic rate, then your heart will be pumping faster in either case. Also, your theory that increased exercise leads to heart attacks is the opposite of reality!
    - emporas 2y ago
      Exercise prevents heart attacks when you have excessive calories, you get adequate sleep and do not sleep outside in the winter, you have a dry place to stand and are not out in the rain and so on. Exercise leads to muscle loss when the fat reserves are depleted and calorie intake is limited. Anyway there are ways to falsify or verify that hypothesis, but it needs some resources, not much but still, it needs time and subjects to test the hypothesis on. So for the foreseeable future, it will stay as it is, a hypothesis.
      - HarHarVeryFunny 2y ago
        If your hypothesis was true, then it'd be glaringly obvious, because there'd be a high correlation between left handedness and increased lifespan.
lolc 2y ago
In your logic obviously the majority of people must be left handed because the left arm being closer to the heart means higher blood flow and thus better stamina. Oh but why isn't it so? Because of venom? Let's set our scientists on that. No wait I got one: Attacking prey is easier with the sun in the back so the hunters would often return from the north. The right handed ones would show better muscle tone in the setting sun and we know women select for muscle mass! Sexual selection baby! Way better story I'm sure you agree. Scientists gotta switch.