Why do we have five fingers?

jepper(55)

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#steemstem

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Asking real questions here, right? But, did you even once think about this? Probably not. Now you do. Wanna know the answer? Read on! :)

It is not only you.

Well, five fingers or toes are quite common throughout the world. Common means that most of jawed vertebrates have this number of fingers. Therefore, we need to travel about 340 million years in the past before the ancestors of nowadays jawed vertebrates evolutionary diverged from other species. Back in the day (meaning around 360 million years ago) there were tetrapods (four-limbed vertebrates) with six or even eight digits. Animals with this number of digits did usually have rather simple limbs, so the answer to this digit reduction might lay in the creation of more sophisticated limbs - with ankles and wrists and stuff.

Is there a reason for number five?

Short answer: No. We have no compelling evidence why number five is better than four or six. And some animals have even fewer fingers and maybe in the future will have even less. Even though this does not say much, it actually states one interesting thing. There is no increase in digit numbers throughout evolution. This is basically a common thing in evolution - it is quite easy to lose something, but immensely hard to regain it. Quite poetic. However, there is probably something to it, because there is truly lack of vertebrates that have six digits. Just look at all the creatures around you, different shapes, abilities, colours, everything, but not single one has 6 fingers? Hell, we even have three eyed lizards and stuff. Weird birdo-mammal-poison-clawed-thing (sorry platypus Perry) and giant hedgehog creatures that shoot needles (porcupine). Yeah pandas and moles have somewhat six digits (you didn’t know that, did you?), but these are just remodelled wrist bones and not new fingers.

Might the answer be sex?

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You didn’t see this coming, right? Neither did I, but it actually makes a bit of sense - kinda. There is this one thing called pleiotropy, which means that some genes have multiple effects upon more than one physical characteristic. And here comes an example in humans called Hand-Foot-Genital syndrome. It is a very rare syndrome characterized by limb malformations and urogenital defects. Interesting notion is that genes responsible for this condition are also part of the set of genes involved in digit number and patterning. So, this doesn’t tell us anything about the reason why we have five fingers. But even when there were some evolutionary attempts to tamper with this number, such changes might dramatically decrease reproductive success and thus these genes would not be passed to next generations.

What makes us special?

Yeah, our number of fingers is nothing but ordinary. On the other hand (pun intended), we are also quite special. Look at your hands, go on. Something peculiar there? Our thumbs! These little fellas set us apart from many other species of animals. Yes, some apes do have them as well, but as a matter of fact ours are much more versatile and independent - apes have extremely limited ability to move just their thumbs. Feeling special now? Yeah, me too.

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Concluding remarks

I don’t know how about you, but I definitely did learn something new today. Hopefully you did like this and if you did, do not hesitate to support me with upvote, comment, or send me karma or chi or whatever. I will probably continue in these “silly” articles, even though I think there is quite some educational value in them.

And wear your fingers with pride, they are actually quite something.

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