/sci/ - Science & Math » Thread #12245099

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Anonymous Sun 18 Oct 11:39:17 2020 No.12245099 View Reply Original Report

Quoted By: >>12245293 >>12245448

What's the evolutionary advantage to having extra arm arteries?

The average human has 2. Some have 3. As time goes on, more and more people have 3. A small percentage now have 4. And that's expected to shift towards the right as time goes on.

What's going on?

Anonymous

Anonymous Sun 18 Oct 2020 11:44:23 No.12245109 Report

Quoted By:

Sexual selection. Chicks dig a dude who can flex in 3 bulges, but most aren't ready for a dude with 4.

Anonymous

Anonymous Sun 18 Oct 2020 13:04:30 No.12245293 Report

Quoted By:

>>12245099
You can shoot up multiple needles at once, girls dig that

Anonymous

Anonymous Sun 18 Oct 2020 13:09:33 No.12245301 Report

Quoted By: >>12246221

It increases blood flow to your mouse hand which would normally be blocked as it rests on your computer desk while your other arm jerks it.

Anonymous

Anonymous Sun 18 Oct 2020 13:21:03 No.12245329 Report

Quoted By:

Making people on /ic/ seethe because you have the +5 DEX artery and they don't.

Anonymous

Anonymous Sun 18 Oct 2020 13:24:42 No.12245339 Report

Quoted By: >>12246024

Third year medical student here. I imagine it's redundancy. If one artery gets blocked, there's three other arteries to supply tissues in the arm. It would also slightly increase the peripheral vascular surface area, slightly reducing your risk of hypertension.

The cost of an extra artery would be slightly more nutrients needed to supply the artery - maybe it wasn't worth it several thousand years ago but in today's era of abundance, it's worth it.

Anonymous

Anonymous Sun 18 Oct 2020 14:04:58 No.12245448 Report

Quoted By: >>12246038

>>12245099
Its thought that within some amount of time, humans will evolve a 6th finger on each hand.
I believe this may be a precursor to that. Build up extra blood flow before seeding the extra digit.

Anonymous

Anonymous Sun 18 Oct 2020 17:37:16 No.12246007 Report

Quoted By:

Wouldnt this be because we sit longer and thus bloodflow is harder? We already know sitting for 8hrs causes vessels to die and etc.

Anonymous

Anonymous Sun 18 Oct 2020 17:40:09 No.12246024 Report

Quoted By: >>12246129 >>12246133

>>12245339
what force would make it prevail? do men with 3 arteries have more children?
is it just genetic drift?

Anonymous

Anonymous Sun 18 Oct 2020 17:44:40 No.12246038 Report

Quoted By: >>12246129

>>12245448
lol never. the 5 finger body structure is dam near universal, in all mammals, It is very difficult for that evolution to occur.

Anonymous

Anonymous Sun 18 Oct 2020 18:12:31 No.12246129 Report

Quoted By:

>>12246024
>>12246038
At least 2 people in this thread understand how evolution works.

Anonymous

Anonymous Sun 18 Oct 2020 18:13:59 No.12246133 Report

Quoted By:

>>12246024
Industrial jobs in the 1700s-1900s required manual dexterity. People whose hands got tired and shaky when doing 6 hours of dexterous work between meals had a disadvantage against handier people.
Handier people had a slight advantage in job prospects and lifetime earnings, which translated into a selection advantage. A successful factory worker gets a wife and 2 kids while somebody who can't hold down a job may not have kids.
Obviously the difference is minor, but even a 5% difference in sexual fitness snowballs into a huge genetic difference over 10 generations.
Modern labour (writing/computers) is even more hands on so this is ongoing.
The interesting thing is whether this applies to first world nomadic groups such as gypsies or if they still have an agricultural society's arm anatomy distribution.

Anonymous

Anonymous Sun 18 Oct 2020 18:41:19 No.12246221 Report

Quoted By:

>>12245301
Ah yes, quite a useful adaptation

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