Human Babies In the Womb Have Lizard-Like Hand Muscles (bbc.com) 74
dryriver shares a report from the BBC: Babies in the womb have extra lizard-like muscles in their hands that most will lose before they are born, medical scans reveal. They are probably one of the oldest, albeit fleeting, remnants of evolution seen in humans yet, biologists say, in the journal Development. They date them as 250 million years old -- a relic from when reptiles transitioned to mammals. It is unclear why the human body makes and then deletes them before birth. The biologists say the developmental step may be what makes thumbs dextrous. Thumbs, unlike other digits, retain an extra muscle.
The biologists are planning more work looking at other parts of the human body in detail. They have already studied the feet and know extra muscles develop and disappear there too while babies grow in the womb. Monkeys and apes still have these muscles and use them to climb and manipulate objects with their feet. Lead author Dr Rui Diogo, from the Howard University, said: "Some of the things we are losing, it's not that we are getting better humans and more progress. No. We are really losing things that will make super-humans. "Super-humans would be keeping those muscles because you would be able to move all your digits, including your feet, as thumbs. "We lost them because we do not need them." Dr Sergio Almecija, an anthropologist who studies ape and human evolution, at the American Museum of Natural History, said the findings provided a deeper appreciation of human development but raised many questions.
"The novelty of this study is that it allows us to visualize -- with precision -- when exactly during our development some structures appear and/or disappear," he said. "The important question for me now is, 'What else are we missing? What will we find when all the human body is inspected at this detail during its development?" 'What is causing certain structure to disappear and then to appear again? We can now see how it happens but what about the why?"
The biologists are planning more work looking at other parts of the human body in detail. They have already studied the feet and know extra muscles develop and disappear there too while babies grow in the womb. Monkeys and apes still have these muscles and use them to climb and manipulate objects with their feet. Lead author Dr Rui Diogo, from the Howard University, said: "Some of the things we are losing, it's not that we are getting better humans and more progress. No. We are really losing things that will make super-humans. "Super-humans would be keeping those muscles because you would be able to move all your digits, including your feet, as thumbs. "We lost them because we do not need them." Dr Sergio Almecija, an anthropologist who studies ape and human evolution, at the American Museum of Natural History, said the findings provided a deeper appreciation of human development but raised many questions.
"The novelty of this study is that it allows us to visualize -- with precision -- when exactly during our development some structures appear and/or disappear," he said. "The important question for me now is, 'What else are we missing? What will we find when all the human body is inspected at this detail during its development?" 'What is causing certain structure to disappear and then to appear again? We can now see how it happens but what about the why?"
What is unclear? (Score:3, Interesting)
It is unclear why the human body makes and then deletes them before birth
What is unclear about this? It happens because the genes which create this outcome have persisted in the gene pool. There's no 'why' about it.
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So, WHY does it persist in the gene pool? Hmm, seems there is a 'why' about it....
Re:What is unclear? (Score:5, Informative)
So, WHY does it persist in the gene pool? Hmm, seems there is a 'why' about it....
Because there is no evolutionary benefit to it being removed. If there is no evolutionary pressure to remove a trait then it can hang around indefinitely until random mutations removes the legacy trait.
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Arguably energy expended developing these structures only to tear them down would be energy that could otherwise be invested in the development of retrained organs and structures. Human babies are already born extremely premature compared to other mammals. I would think anything that could be done increase the developmental state of babies prior to birth without sacrificing brain development would have been evolutionary advantageous in terms of survival rate.
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The energy benefit would be microscopic. The cells that are torn down can be recycled for their raw materials, so very little is lost. And evolution only works in small steps, where each step needs to show a benefit. It is quite likely that the development of these structures overlaps with the development of other structures. In that case, you can't just remove the genes for development, because it would impact something else.
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There are some bold implied assumptions in this and a very big one is that there aren't humans walking around who still have these structures.
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Development, particularly embryonic development, is really complicated, with lots of local minima. You need strong selection pressure to climb out of those minima. A little bit of energy expended developing vestigial features usually isn't enough.
Humans have vestigial tails as embryos (all mammals without actual tails do). Whales and snakes have vestigial legs.
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Arguably energy expended developing these structures only to tear them down would be energy that could otherwise be invested in the development of retrained organs and structures. Human babies are already born extremely premature compared to other mammals. I would think anything that could be done increase the developmental state of babies prior to birth without sacrificing brain development would have been evolutionary advantageous in terms of survival rate.
You're trying to apply logic to a real-life "drunk walk" algo influenced by complex external chaos. Evolution doesn't work the way you think it does.
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Human babies are born premature because them growing any larger presents a significant life threatening situation to the mother. The survival rate of human babies in the last 60 years is beyond great, so no need to develop further.
On the other hand look at kangaroos and cats. Their babies are born even more premature than us. Survival rate in 30 days for them is about 50%.
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Without being an evolutionary biologist, maybe these serve atransitory useful function that hasn't been identified yet - hypothetically, maybe, creating structures that bones follow for growth, or a scaffold on which other structures rely. Hopefully research and closer analysis will provide some clues.....genetics is anything but simple.
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"Because there is no evolutionary benefit to it being removed."
No, of course there would be a benefit to it being removed if these structures are not necessary to the growth process. It's just one more place that errors can occur, in that case.
Either that is a necessary step in our development based on where our genes came from and how the whole system works, or it just hasn't had time to go away yet. I'm betting on the former.
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There is an assumption in there that however small a benefit would be it will still prevail in the noise of all the other effects and have an effect on evolution.
there is another assumption that evolution has a finegrained control allowing to tune individual features.
I think both are unlikely to be true. For the first, the random drift in evolution is probably larger than then one provided by tiny benefits.
For the second, that won't work when every switch you flick has impact on a lot of seemingly independe
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There is an assumption in there that however small a benefit would be it will still prevail in the noise of all the other effects and have an effect on evolution.
It will, given enough time, which I postulate may not have passed. Read my comment.
there is another assumption that evolution has a finegrained control allowing to tune individual features.
Hence my belief that it probably cannot go away. Read my comment.
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Because there is no evolutionary benefit to it being removed. If there is no evolutionary pressure to remove a trait then it can hang around indefinitely until random mutations removes the legacy trait.
This is a narrow view of evolutionary efficiency. Whether harmful or not, if something is not needed, then evolution WILL remove it. Vestigial organs are an example that may fully disappear in time in humans.
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Exactly, also evolution is a tinkerer not an engineer. So if the steps to get from state A to state C is A->B->C, then evolution have a hard time to select for A->C, with step B removed, since the result is C in both cases...
So unless there is a clear survival bias for A->C over A->B->C, the B step will never be "erased".
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Okay, smarty boots, so why have the genes persisted?
Here's my theory: the process doesn't work any other way. Something about building those muscles is critical to development of the hand as we know it. Maybe some part of the structure remains during the next phase of development.
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You're wrong as usual, drinkyourpoo.
It is obviously God telling us that a fetus is just a lizard and can be aborted at any time.
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Here is a thought, it isn't so much that the genes have persisted as that the genes which retain those structures were compromised by later additions but "human" is not a single genetic line. I'd hazard a guess that there are people who do have these muscles and they just weren't in the study. I saw a show by Stan Lee documenting super-humans which documented a boy who could use feet like hands. I myself can not but I'm baffled trying to figure out what they might mean by extra dexterity in my thumb vs othe
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It's clear you're a programmer and not a biologist.
Biological development and evolution do not work in a linear, sensible fashion. It's messy, counter-intuitive, and often very inefficient and wasteful. One of the best arguments against intelligent design is how stupid a lot of evolution has been. And no, this isn't a subjective "I think that's dumb", it's objectively bad things that evolved or persisted through evolutionary processes, or very beneficial traits that went away. (Like these muscles.)
People ge
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Biological development and evolution do not work in a linear, sensible fashion. It's messy, counter-intuitive, and often very inefficient and wasteful.
Which reminded me of an interesting experiment with certain fish that found homosexual behaviour increases male attractiveness to females [royalsocie...ishing.org]
If I had to sum up nature, it'd be "whatever works".
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Why? Ontology reciprocates phylogeny.
I'm sure someone will point out that this confirms the existence of Lizard People.
WHOA WHOA WHOA (Score:1, Troll)
You said baby. Its a fetus, so we can abort it if we want to.
Re: WHOA WHOA WHOA (Score:3)
You can abort babies too. Adults as well are aborted if they commit the wrong kind of murder in Texas.
Scaffolding? (Score:5, Insightful)
The most likely explanation is that they don't have any negative effects, but the growth of other musculature/ligaments depends on them as scaffolding. Then they fade away (reabsorbed) as they're not needed for anything. So while they're not useful as for movement, they're probably useful during development.
There are lots of little things like this in the body, kind of like the weird quirks when programs are updated and built on top of other older programs that were built around other older programs and you end up with weird patterns of behavior that don't do anything but nothing will run without (time to rewrite from scratch and create a whole new mess of bugs!).
Sam
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Given how much we do not know about the human body, and the trend towards repeatedly finding a critical use for what was once deemed "useless" (the appendix for example may actually be a backup storage for the gut microbiome, recent findings about the nature of DNA and it's 4-dimensional expression mean the large portion of the human genome that was thought to be useless may all have functionality, and finally the notion that 90% of the brain is unused has also been found to be rubbish), I suspect we'll fin
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The most likely explanation is that they don't have any negative effects, but the growth of other musculature/ligaments depends on them as scaffolding. Then they fade away (reabsorbed) as they're not needed for anything. So while they're not useful as for movement, they're probably useful during development.
Yeah, biology is Rube Goldberg machines all the way down. There are many cellular processes that keep performing the same action and fail a bunch of times until the build-up of failures causes the umpteenth instantiation to succeed. Evolution selects systems that work but only just barely.
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"but only just barely."
Well not really. You need some form of redundancy and resiliance to adverse conditions whether they be outside or inside the body. If biological processes only just worked then we'd probably all drop dead the minute the temperature rose or fell a few degrees.
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Thats due to the limits of the chemistry, not evolution. Evolution has done a pretty good job given the physical limits its working with.
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100% wrong. Evolution isn't the limiting factor, chemistry is.
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Which is the same thing. Otherwise, nobody stopped evolution from having selected better chemicals from the beginning.
Note that just because we haven't found better chemicals does not mean there are no better chemicals.
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Now if 'God' could have spent a little extra time on writing a full suite of unit and integration tests, we wouldn't be so backed into a corner!!!!
And human embryos look similar to most life (Score:4, Interesting)
Fish, amphibian, reptile, bird (that's the image, all mammals look similar as well of course).
Such is the beauty of evolution.
https://www.invitra.com/en/dif... [invitra.com]
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Fish, amphibian, reptile, bird (that's the image, all mammals look similar as well of course).
Such is the beauty of evolution.
https://www.invitra.com/en/dif... [invitra.com]
Yes, all life on earth is related. Plants are even related to animals and vice versa.
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Fish, amphibian, reptile, bird (that's the image, all mammals look similar as well of course).
Such is the beauty of evolution.
https://www.invitra.com/en/dif... [invitra.com]
Yes, all life on earth is related. Plants are even related to animals and vice versa.
I was looking for this.
It gets little exposure perhaps for religious reason. It's the "Humans are not animals," thing. Embryos go through development stages that repeat their origins. All life has a single origin. That makes sense. All life evolves over time and variations and differences occur.
Still, the origin never changes.
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Taylor Swift (Score:1, Troll)
Taylor Swift never lost her reptilian fingers in the womb... or her reptilian face.
Or maybe... (Score:2)
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Do baby lizards have human adult-like muscles?
Gills (Score:2)
Its been known for ages that all mammalian foetuses have gill like structures briefly appear whilst developing so this is just another example of the same phenomenon. Presumably these structures grow because the genes still exist and do no harm but only get switched off later and then the cells of these structures get repurposed by newer genes.
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Human embryos do not have tails.
Alternative explanation... (Score:2)
Human feet adapted for bipedalism (Score:1)
Question (Score:1)
Almost everything! Just think visible spectrum to full spectrum - patterns in a million dimensions which are changing all the time! I'm amazed I can type this!
God is Great (Score:5, Funny)
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What is "random"? Ever drop a ball of wool on the floor? Those knots are just too complex to be random.
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I've spent alot of time looking at other peoples code ...... I'm certain aliens are involved somewhere.....
The Lizards! (Score:4, Funny)
Clearly these scientists stumbled on one of those lizard people who secretly run the place.
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So sometimes I have ideas which are just the same as those of dozens of othre people. It's a humblin thought
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So sometimes I have ideas which are just the same as those of dozens of othre people. It's a humblin thought
Sometimes I have ideas which are just the same as a lizard. That's why I wear a turtleneck.
Shhhhh..... (Score:3)
Don't feed the Scientologists. I don't want to hear any more shit about the reptilian brain.
Reusing good ideas. (Score:2)
Design reuse means that the hard drive "evolved" from the reel-ro-reel player. ;-)
Recent lost (Score:1)
Wait... They say that other hominides has the feature, so even if the feature appeared on reptiles, its functionality was last just recently...
Then the explanation is simple. The mutation that remove them is very recently, probably when we leave the trees. That inverse mutation don't remove the muscles at all, but reabsorves the muscles during the development.
Nvegative mutation, neutral or some positive trait is just for discover.
In any case, it doesn't matter if the trait is ancient, but when was lost in t
I, for one, ... (Score:1)
welcome our reptilian overlords.
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Dude, don't you see. We are the Reptilian Overlords. We kept the secret so well even we didn't know it.
We've been ruling ourselves the entire time!
IOW (Score:2)
Don't change a working construction plan.
Lizards (Score:2)
Have you seen a baby? (Score:4, Funny)
Reptillians! (Score:1)
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Now this will lend credibility that we are ruled by the Reptillians.
Expect many more "Obama is a Reptillian", "Trump is a Reptillian", etc. super conspiracy theories.
We see this today.
The House is controlled by Democrats and the Senate by Reptillians [sic].
Does explain... (Score:2)
... the chicken taste...
This was covered by Dr Who (Score:1)