1 yr. ago • 78%

I just realized how incredible it is that we don't have toes growing out of our ears.

AFAIK it all boils down to the fact that during embryonal development our cells, which at that point were just a blob of undifferentiated autonomous chemical machines, somehow managed to unanimously agree upon the cardinal directions (up-down, left-right, front-back) for future development - and thanks to this, we don't have toes growing out of our ears.

41 comments

Pass the joint, bud.

60
- Heh, “bud”
  
  4
  
  That's what SHE said! Wait. What?
  
  3
It's not that incredible, considering we can get cysts full of teeth and hair inside the body

47
- How do I unread this
  
  16
- Oh yes, teratomes are not fun. But thankfully they are comparably rare.
  
  7
- Imagine if you suddenly sprouted a tumor with functional tastebuds in your colon
  
  6
  
  "So what brings you into the doctors office today?"
  
  "Well for some reason everything I eat ends up tasting like shit."
  
  4
  
  Ugh and I thought burping after having Fish Oil pills was bad…
  
  1
- Wonder if we could use that phenomena to regenerate teeth in a lab for replacements and dentures.
  
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  Probably no different than stem cell stuff
  
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I mean, that's what dna is for. These machines aren't operating blindly (or even "cooperating" or agreeing on anything, really). They're following the code that makes up who we are.

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- Yeah but it's crazy how any given cell knows where in the body it is, somehow.
  
  6
  
  They don't so much know where they are as much as they're just interacting with what's there in the way they were made to, which was all put there due to the DNA to function as a whole.
  
  And to be clear, it's all still amazing, just in a different way. Here's Kurzgesagt video that helps explain how these cells "communicate" to do things like put a body together in the right order.
  
  9
- Those who don't usually don't make it far.
  
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  Survivorship bias
  
  1
- Someone was probably born with toes on their head in the past and life didn't go so well that they could have children that also survived. This is why our DNA doesn't have instructions for growing toes on our head.
  
  2
- Sure, but every cell has the same DNA. Yet some "decide" to "agree" on making toenails, while others differentiate into eyes.
  
  0
  
  If an embryo decides to split in two, and then sends out the marker that "this is the right side" and it's too close to the other embro, there will be a set of identical twins, but one will have the heart on the right side, appendix on the opposite side etc. This needs to be known if the "mirrored" person has a colonoscopy, since the colon is folded the opposite direction.
  
  3
The toes are the powerhouse of the foot

16
That's the core of evolution: Beings with unfavorable features simply don't make it.

15
- Too bad evolution is blind, and now our windpipes and digestive tracts cross over. It works, but it would have been nice if choking wasn't a thing.
  
  Other examples of interesting (sometimes called 'unintelligent') evolution might be how we walk upright, leading to complications with childbirth and back pain, blindspots because of our optical nerve, and or that recurrent nerve that does a random U-turn.
  
  Evolution is basically a centuries of patches without ever getting a rebuild form the ground up. It's mostly ok, but some bugs stick around
  
  27
  
  Interestingly, the recurrent laryngeal nerve is looped around that way because the structure of the nerve grows in before the structures of the aorta and other large vessels fully grow in and orient into their correct position, so the nerve ends up looping around them.
  
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  We just walkin' with a couple billion years of biotech debt in us.
  
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  I always thought that was a poor design. Aliens likely would find that disgusting.
  
  What interests me is that I believe all warm blooded animals also share this trait. Not certain that is true but if so, wouldn't that mean it evolved in a very early period?
  
  Also what I find interesting is that the layout of humans to most animals is the same. A head with eyes then nose then mouth among with the brain behind it. Most of the organs are in similar locations. It seems strange that there would not be more variety.
  
  3
  
  This is just based on an offhand comment from a lecturer during a practical session during my time studying animal management in college, not directly from a biology lecturer so citation needed, but apparently rabbits don't have a combined windpipe/digestive tract and it means that a blocked nose can kill them. So even if choking wasn't a thing we'd have to worry about something blocking our noses and suffocating us.
  
  3
  
  That 85% of DNA that apparently does nothing? Commented out.
  
  1
In science that is called symmetry breaking (going from a homogeneous blob to left right something) and a very active topic of Research.

11
I can't comment on anyone with toes out of their ears, but I've seen a lot people with their butt where their face is. Or at least it would appear so, as a lot of shit seems to come out of the hole in their face.

All jokes aside, nice shower thought though!

10
Gravity is what makes this happen. Guess what probably is a concern in space?

1
- You know that we've gestated various animals in weightless conditions on the ISS, yes? They look normal.
  
  17
  
  We have? Do you have a source for that? That would be amazing. :)
  
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- Toe ears?
  
  8
You JUST realized that. 🙄

-4
- I mean, there are a lot of things that we've always "known", but one day you just really thing about it and realize how fucking wild it is.
  
  8
- That's why there is an entire community for shower thoughts: because people sometimes get these sudden realizations. But honestly, you got me - I realized it a few days ago and only got around to post it "now".
  
  4

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