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I'm finding the headline is remarkably annoying. Evolutionary pressure is pretty brutal to things that actually aren't used - building a muscle takes energy an

by roenxi 2y ago

I'm finding the headline is remarkably annoying. Evolutionary pressure is pretty brutal to things that actually aren't used - building a muscle takes energy and is one more thing for the body to maintain. I don't see how it is fair to say "thought humans didn’t use". It is always "if it has a use, we aren't sure what it is yet". Nature isn't a perfect architect but the odds are just much better that the use is still to be discovered than that truly useless bits of the body exist.

lgeorget 2y ago
When I read "humans didn't use", I understand that other animals with which we share close common ancestors still use it. Evolutionary pressure can make organs go into disuse so it makes sense that we end up with unused organs.
- parineum 2y ago
  Evolutionary pressure also would select for not wasting energy on a useless organ.
  - _Algernon_ 2y ago
    The selective pressure of small unused organs may be very low and virtually disappear in the stochasticity of natural selection. It may take a long time for such elements to disappear completely
- roenxi 2y ago
  A 1% reduction in body mass is a huge advantage evolutionary, especially since rather than being cut completely that mass could be repurposed as more muscle for competing or more fat for lean times. For something in very recent evolutionary history (talking the last few thousand years), yeah sure the pressure might not have optimised a wasted organ out. But for any random organ? Nah, they probably have a purpose and we don't know what it is yet. Otherwise there is a big advantage to removing 'useless' bits. Evolutionary processes do however love little random tweaks and whatnot because they serve a useful purpose in weird edge cases and it is much more likely we're looking at one of them in any particular case.
  - jjk166 2y ago
    And the ability to breath fire would also be a huge advantage, but evolution does not seek advantages, it merely keeps mutations that happen to be beneficial. No one has been born with a mutation that has allowed them to breath fire (or if they were they obviously didn't have much reproductive success) and thus we are still unable to breath fire. No one who has been born with a mutation that prevents the development of ear muscles has had especially great reproductive success either.
    - roenxi 2y ago
      Well no, being able to breath fire is probably evolutionarily stupid. There is no reason to think it would be helpful, it'd presumably involve animals building up a highly flammable concoction inside their bodies and occasionally exploding. For no gain, since they could do what everyone else does and gather combustible material and set it alight. And flamethrowers just aren't very effective weapons on average since they'd tend to burn an animal's home down or be very energetically demanding for no upside vs something like a good pair of jaws or claws. If evolution can figure out photosynthesis it can figure out flammability. Flammability is actually pretty easy. Even monkeys can manage it. There probably have been animals that breath fire and it just didn't catch on because it is wholly impractical.
      - jjk166 2y ago
        Substitute any other adaptation that provides benefit but for which the necessary combination of mutations is unlikely to occur.
  - dahart 2y ago
    > A 1% reduction in body mass is a huge advantage evolutionary That thought fails to explain the wide natural variation in body mass of humans, and within each species on this planet. Edit: for most species being smaller is a disadvantage. Mates statistically select for larger stronger individuals, and larger stronger individuals are statistically better at killing and defending.
tbrownaw 2y ago
> I don't see how it is fair to say "thought humans didn’t use". Did you not learn about "vestigal organs" in grade school? Maybe consensus has changed lately, but that at least used to be a thing.
- roenxi 2y ago
  What, if you learn about something at school it is automatically true? The same criticism applies there too. They were calling things like the appendix vestigial when it obviously isn't. People made a big deal about how it doesn't do anything and then it turns out it does something. Who'd have guessed. The so-called vestigial organs probably all have uses. I'd have a much easier time believing most of them do than none of them. Otherwise evolution would have done a much better job of weeding them out.
  - tbrownaw 2y ago
    > What, if you learn about something at school it is automatically true? It's a decent indication that people thought it was true.
  - dahart 2y ago
    > The so-called vestigial organs probably all have uses. You’re right that some organs have been labeled vestigial and turned out not to be, but there are other organs that we know are vestigial because they don’t occur in all humans (same goes for other species). Evolution doesn’t weed things out without there being relatively strong effects on survival, and some of these things don’t affect survival so they drift. This also isn’t binary. There are organs that are still classified as vestigial, but have minor or secondary uses, perhaps enough for evolution to keep them around, or again perhaps because having them doesn’t result in any statistical mortality. Speculating and/or carrying beliefs that contradict modern evolutionary biologists probably isn’t going to work out. School might not be always right, but it is most of the time, and it’s right more often than no school, right? https://en.wikipedia.org/wiki/Human_vestigiality https://en.wikipedia.org/wiki/Human_vestigiality
    - 2y ago
throw7474847 2y ago
[dead]
dahart 2y ago
There is only evolutionary pressure on things that affect mortality. Vestigial organs can and do exist because there is no evolutionary pressure on them, because they don’t affect mortality.

by roenxi 2y ago

lgeorget 2y ago

When I read "humans didn't use", I understand that other animals with which we share close common ancestors still use it. Evolutionary pressure can make organs go into disuse so it makes sense that we end up with unused organs.

parineum 2y ago
Evolutionary pressure also would select for not wasting energy on a useless organ.
- _Algernon_ 2y ago
  The selective pressure of small unused organs may be very low and virtually disappear in the stochasticity of natural selection. It may take a long time for such elements to disappear completely
roenxi 2y ago
A 1% reduction in body mass is a huge advantage evolutionary, especially since rather than being cut completely that mass could be repurposed as more muscle for competing or more fat for lean times. For something in very recent evolutionary history (talking the last few thousand years), yeah sure the pressure might not have optimised a wasted organ out. But for any random organ? Nah, they probably have a purpose and we don't know what it is yet. Otherwise there is a big advantage to removing 'useless' bits. Evolutionary processes do however love little random tweaks and whatnot because they serve a useful purpose in weird edge cases and it is much more likely we're looking at one of them in any particular case.
- jjk166 2y ago
  And the ability to breath fire would also be a huge advantage, but evolution does not seek advantages, it merely keeps mutations that happen to be beneficial. No one has been born with a mutation that has allowed them to breath fire (or if they were they obviously didn't have much reproductive success) and thus we are still unable to breath fire. No one who has been born with a mutation that prevents the development of ear muscles has had especially great reproductive success either.
  - roenxi 2y ago
    Well no, being able to breath fire is probably evolutionarily stupid. There is no reason to think it would be helpful, it'd presumably involve animals building up a highly flammable concoction inside their bodies and occasionally exploding. For no gain, since they could do what everyone else does and gather combustible material and set it alight. And flamethrowers just aren't very effective weapons on average since they'd tend to burn an animal's home down or be very energetically demanding for no upside vs something like a good pair of jaws or claws. If evolution can figure out photosynthesis it can figure out flammability. Flammability is actually pretty easy. Even monkeys can manage it. There probably have been animals that breath fire and it just didn't catch on because it is wholly impractical.
    - jjk166 2y ago
      Substitute any other adaptation that provides benefit but for which the necessary combination of mutations is unlikely to occur.
- dahart 2y ago
  > A 1% reduction in body mass is a huge advantage evolutionary That thought fails to explain the wide natural variation in body mass of humans, and within each species on this planet. Edit: for most species being smaller is a disadvantage. Mates statistically select for larger stronger individuals, and larger stronger individuals are statistically better at killing and defending.

tbrownaw 2y ago

> I don't see how it is fair to say "thought humans didn’t use". Did you not learn about "vestigal organs" in grade school? Maybe consensus has changed lately, but that at least used to be a thing.

roenxi 2y ago
What, if you learn about something at school it is automatically true? The same criticism applies there too. They were calling things like the appendix vestigial when it obviously isn't. People made a big deal about how it doesn't do anything and then it turns out it does something. Who'd have guessed. The so-called vestigial organs probably all have uses. I'd have a much easier time believing most of them do than none of them. Otherwise evolution would have done a much better job of weeding them out.
- tbrownaw 2y ago
  > What, if you learn about something at school it is automatically true? It's a decent indication that people thought it was true.
- dahart 2y ago
  > The so-called vestigial organs probably all have uses. You’re right that some organs have been labeled vestigial and turned out not to be, but there are other organs that we know are vestigial because they don’t occur in all humans (same goes for other species). Evolution doesn’t weed things out without there being relatively strong effects on survival, and some of these things don’t affect survival so they drift. This also isn’t binary. There are organs that are still classified as vestigial, but have minor or secondary uses, perhaps enough for evolution to keep them around, or again perhaps because having them doesn’t result in any statistical mortality. Speculating and/or carrying beliefs that contradict modern evolutionary biologists probably isn’t going to work out. School might not be always right, but it is most of the time, and it’s right more often than no school, right? https://en.wikipedia.org/wiki/Human_vestigiality https://en.wikipedia.org/wiki/Human_vestigiality
  - 2y ago

throw7474847 2y ago

[dead]

dahart 2y ago

There is only evolutionary pressure on things that affect mortality. Vestigial organs can and do exist because there is no evolutionary pressure on them, because they don’t affect mortality.