[lgeorget]

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.

[roenxi]

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]

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]

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]

Substitute any other adaptation that provides benefit but for which the necessary combination of mutations is unlikely to occur.

[dahart]

> 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.

[JoeAltmaier]

A little study of biology will clear that up. Species inhabit different niches. They have different survival strategies. Each case requires a different optimal point.

[dahart]

Please elaborate, I think you misunderstood me. Are you defending the claim that 1% human body mass reduction is an evolutionary advantage? Your quip about biology should maybe be directed at @roenxi?

I was talking about variation within each species, not across different species. (Edited to clarify) I was talking, in context as a reply to the claim that losing a given vestigial organ would improve (lessen) mortality. Humans, for example, have wide natural variation in body mass, therefore the evidence contradicts the claim that “1% reduction in body mass is a huge advantage evolutionary”.

If a reduction in body mass was an evolutionary advantage, we’d be evolving to be smaller over time. That’s not happening. Why?

In fact, there is an evolutionary advantage in humans to being taller and having more muscle, since these traits are selected for by mates, and are beneficial for hunting.

[JoeAltmaier]

That is the naïve one-variable approach which breaks down immediately. Features all evolve together, the individual thrives or dies as one organism.

Any change in one variable affects all the others, e.g. drop body mass releases calories for other survival purposes. Any increase over the critical need consumes resources better used for other things.

[dahart]

> drop body mass releases calories for other survival purposes. Any increase over the critical need consumes resources better used for other things.

Hahaha you just made the exact naive one-variable mistake you accused me of once sentence earlier. Can you point to any evidence whatsoever that reduced body mass is beneficial for human evolution? Back your claim up. Show me. Where is it? Losing body mass is an evolutionary disadvantage at least as often as it’s an advantage, which is why humans are evolving to be larger over time and not smaller. Unfortunately, reality doesn’t back up yours and @roenxi’s claim about body mass vs evolution.

It seems like you’re making stuff up and moving the goal posts. We’re talking about evolution, and you’re defending @roenxi’s claim that having 1% less body mass is a huge evolutionary advantage, so tell me what calories are “released” with lower body mass when an individual is compared to it’s neighbor? Where were they being held? Please define “critical need”. What “other things” will these released calories do? You’re making an enormous number of unexplained assumptions.

Body mass is beneficial for hibernation in many species, beneficial for energy to survive winters and periods of no food, beneficial for muscle growth for hunting and attracting mates, beneficial for defending one’s self, etc. etc. I mentioned those last two already and notice you quietly ignored them without being able to address them at all. Having lower body mass than neighbors makes an individual more likely to be prey, less likely to succeed at hunting or mating, and gives them a shorter survival time without food.

You’re certainly not convincing me you have a grasp on evolutionary biology, but by all means continue the thinly veiled insults and smug remarks that attempt to compensate for it, and maybe you’ll win some internet points.

[parineum]

Evolutionary pressure also would select for not wasting energy on a useless organ.

[_Algernon_]

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