Also, the extra digits on ichthyosaurs always fascinated me. Yes tetrapods settled on five as the ancestral condition for all living land vertebrates.

@@sahb8091 EA I

Please cut the jokes part we all know it's awkwardly corny.

I'd rather have facts trivia at the end of each episode...

Like: Do you know that water is wet? Or.. Every 60 seconds in Africa, a minute passes... Lol just kidding corny as heck too 🥲🤣

Interestingly they also evolved from the omnivorous diet of their ancestors to a diet of bamboo only. Perhaps the "hand stick" has something to do with the diet modification. I'm certainly no expert though.

@@gaufrid1956 from what I've been told its basically to help them hold bamboo. You can watch them eat and they use all six "fingers" to hold the stalk properly.

Perhaps all of this 'hand stick' accounts for why pandas don't breed as much as they maybe should. 😐

@@tsopmocful1958 I dont see how that would affect pandas breeding

and hedgehogs which have a modified wrist bone to create a sixth digit to improve burrowing.

Because they were mostly not exposed to the elements.

As an amateur's guess: raw statistical occurrence, luck, and paleontologists having learned very carefully how to look for them. Of all the footprints an animal makes in its life, taken over the thousands to millions of years that species/lineage could be around, ploriferating to incredible numbers, at least some of them will be covered up in such a way that the mud will dry up into s clear fossilized shape. Most of those fossils are effectively buried forever for us, lost as a grain of sand in a beach of searchable locations, but the few places we've learned hold these fossils (due to soil composition or access to ancient eons of earth) and experts in their fields have learned how to find them and how not to break them while excavating.

That said, yes, I would absolutely love an episode dedicated to how Trace fossils form and how they're found by paleontologists. I Dinosaurs and Funky Little Walking Fish as much as anyone else, but I wish paleontology as a form of study got more of a spotlight, because the little I've seen makes it look really really cool

I thought this was about to turn into a "dinosaurs aren't real" comment. I legit met a man who believed that.

Fossilized footprints are generally Footprints in mud that quickly get covered up by something like ocean floor sediments. Or they get covered up by something like a landslide or ash from a volcano eruption. They remain covered up for thousands or millions of years and then through natural plate tectonics, weather changes, and other factors, the fossilized footprints are exposed again for us to find. If they remain exposed to the elements, then they don't fossilize.

Good point.

I doubt it, for the reason that we were also used to count to 60 with our two hands (the Sumerians started with it, things like a circle being 360 degrees is a relic of that time), yet we lost it over time to only using a decimal system

@@bartelvandervelden9894 I think the point is that we only used a decimal system in the first place because we have 10 fingers. We don’t use base-60 or base-16 because they’re a lot less intuitive to count on your hands

@@Srothics there’s also the binary system of counting things, besides the decimal, hexadecimal, base-60 systems. But, you’re right, base-10 is our preferred methods because of its more intuitive to us.

@@bartelvandervelden9894 sumerians counted using their finger folds

I completely agree! A few extra fingers wouldn't benefit me much, but I could go for a third or fourth arm!

More groceries you can carry at ones from car to door.

You clearly have never played piano :D Another index finger would be awesome

There's also playing guitar, doing crafts where you have to hold things down with your fingers, having more fingers to hold An Piece Of Tape when you're gearing up to tape the heck out of something... I still kinda agree - I do wish for an extra arm more frequently, but I do still regularly wish for more digits lol

having another thumb by your pinky would make it rather easy to open stuff like bottles with just one hand, so theres that lol

I legit lolled much when that came up

“This thing looks kinda derpy… what are we gonna call it?” “Can you imagine if we called them ‘derpies’?!” “OMG! Well, the scientific community won’t accept that (even though there’s a bird called a booby, another bird called a tit, and a fish called ‘Boops Boops’), but maybe we can try to hide it ever so slightly. Only we will know ;) “ Final name: Pederpes

Yeah, I smiled a lot at the name. I think it means something like "foot of Peter" though. Anyway, definitely naming my next Quagsire that.

@@rasmusn.e.m1064 Peter means stone as well, so the well goes deeper

pederpy

I was never even early

Same

@Leo the Anglo-Filipino ur parents may be related.

Lol

Left yourself open there my friend :P

It’s very difficult for existing structures to fuse as opposed to duplicating or expanding upon a single structure. Losing extra fingers and reinforcing existing ones is a more feasible evolutionary path, which you will see if you look more into how genes tent to express morphologically. You also won’t see thumbs appear for hundreds of millions of years. I suppose anything is possible but it’s difficult to see this being a plausible bath of evolution

it's not just you; I had the same reaction the the 3+4 config.

That thought occurred to me as well.

@@W333L Don't we have tons of examples of structures fusing, both evolutionarily and developmentally? Aren't bird wings three fused dino fingers?

@@seleuf think about the central claim. In all tetrapod derived groups we see each digit vary in shape, size, location etc. Your example is a great illustration of wrist and hand bones for example, where fusion and reorientation happens constantly among related species, though these bones rarely fuse into a single undivided structure. Bird wing skeletons have clear division clefts between each digit to form a structure that looks nothing like a paw or flipper, though each digit is a self contained bone that attaches to the other arm bones (we even see some digit deletions). What you don’t see, however, is two finger digits fusing into a thumb. We would have a clear division cleft at some point in the fossil record to explain this, and it’s simply astronomically easier for an organism to lose an unwanted digit through a deletion mutation or gene silencing rather than spend hundreds of thousands of years melding the bones into one.

The thing is, bears aren't carnivores.

@@aaaaa359 that I know but they’re in the order Carnivora. That’s what I was meaning.

They are just faking it! They eat parts of the bamboo that are super high protein and still have the digestive tract of carnivores.

The first bear (dawn bear) was believed to be omnivorous, I think. And then evolved and diverged into mostly omnivores, with carnivorous polar bears on one end of the spectrum and herbivorous panda bears on the other. So basically the fearsome carnivore aspect came later.

Totally irrelevant answer. "Religion".😂😂

Only sort of. These are in no way similar to the old fins. It's just a covergently evolved structure that functions as fins. It's still impossible to truly regain what was lost.

But note how they haven't regained their gills yet & still use lungs, despite being aquatic.

I was wondering, are those 6 fingers fully functional? Are the just as strong and gripping as 5 fingers? I imagine that it's not only the existance of the digit, the true power of the hand is in the arm, the muscles pulling on the tendons to make me type this.

@@rickglorie I know there is a family where every single person has 6 fully functional fingers on each hand

@@rickglorie “the true power of the hand” *avengers theme intensifies*

The genes involved in having a sixth finger also control the likelihood the person will kill Inigo Montoya's father and need to prepare to die, thus explaining why it remains a rare trait.

It's no hypothesis: the gene regulatory network that produce digits in tetrapods is pretty well known and some of the genes involved, like Sonic hedgehog and the hox genes, play key roles in the developments of other organs, such as the central nervous system for Sonic hedgehog and the spine for hox.

No. Fins aren’t hands. Look up the fish skeleton, it has bones driving four limbs built out as fins, but more fins are controlled by just muscles. Fins are cartilage with skin stretched over them, think of them like your foot slipped into a scuba fin. The wiring and subroutines to use digits need to be accounted for - five, set up as two, two, one (opposing digit) comes from ancient claws and works well. Add a sixth and it gets ferociously complicated!

@@elizabethclaiborne6461, Hmmm. Well, I know they aren’t the same, but every depiction I have ever seen of the land vertebrate ancestor(s) has been a lungfish like creature with little, arm-like, stubs between its body and fins. Every text book I’ve looked at (granted that was decades ago) has described the transition from fully aquatic vertebrates to fully terrestrial vertebrates as involving air bladders evolving into lungs and fins evolving into limbs. If I’m wrong, and hands, feet, arms and legs did not evolve from fins, I must say I am positively mystified as to how we evolved such appendages and what from.

Selective pressure is provided by the environment and actively selects the surviving traits. Selective pressure allowed five - digit-handed creatures to live on and pass their genes on while those with more digits could not use them efficiently to live to pass on their genes. The polydactal animals were selected against. That is how selective pressure works. Another example: amphibians come out on land, but they are still tied to water in order to lay and fertilize their jelly - like eggs. They cannot stay out of water their entire lives. Reptiles had developed the shell - enclosed egg, and when they ventured into land, they could stay there permanently because the eggs could fend off the drying effects of weather and still allow embryos to develop into offspring. Frogs cannot spawn on land. Selective pressure prevents them from living on land and spawning there. There was no selective pressure to keep reptiles like alligators spawning in water, though there is an advantage gained from returning to the water for some activities. But reptiles can lay eggs, eat and live in even the most arid of environments.

Outside a civilization where it's necessary to wear five-fingered, industrially produced gloves that stands for, at the very least, hundreds of thousands of years but doesn't invent the technology necessary to cut off supernumerary digits, what's the selection pressure that makes 5 the ideal number? Whale hind limbs became weak and useless due to a change in lifestyle; they disappeared because even vestigial hind limbs create extra drag relevant for survival. On the other hand, if a lineage that just so happened to have five fingers per hand/foot, rather than seven, four, or three, also had something else that gave them an advantage, the number 5 would be mostly preserved without any real pressure -unless a specific descendant lineage (horses...) developed into a very specific direction.

@@adlockhungry304 limbs absolutely evolved from fins, they even use the same genes that fish use for fins. Since we are lobed finned fish our genes for our limbs should be more related to the genes in a coelacanth than in marlin or any other ray finned fish.

Does he climb walls??

I heard that polydactyl has dominant genes, so even if he get a surgery, his children might still be affected.

@@mrvn000 Probably not but no doubt as a child he had no problem learning his 6 times table 😉

Your nephew is Stanford Pines from Gravity Falls

In India they think that your nephew is extremely lucky.

the alternate earth of an arthropod, fungi and plant land life, where vertebrates just didn't bother, seems like a dope concept lol

do we know if tiktaalik generated an environmental change which suited early insects (eg perhaps by depositing concentrated food supplies on beaches?...)

Most of the stuff about early tetrapods is almost entirely speculation will very little evidence. In fact I remember reading an article which did a fairly comprehensive study of several of these early tetrapods which were sufficiently well preserved that their muscle scar attachments of skeletal digits sufficiently preserved to allow the muscles to be reconstructed and worse many of them lacked the spinal musculature to even crawl on land any better than a beached whale generally indicate the early tetrapods couldn't support their weight out of the water at all. Couple that with work showing they likely lacked the sensory apparatus to see effectively on land based on the shape of their eye sockets (though one of them ironically one of the earlier ones did have eyes that were probably adapted for land as they were positioned like a crocodile to see out of the water while submerged and its jaws left no doubt about what it was using those eyes to do. Still that was one of the fossils that would fare about as well as a beached whale on land so it was probably a pretty risky strategy dependent on its ability to drag prey back into the water in a sudden strike) It has been several years but I remember reading a fascinating article which looked at some changes in musculature which identifies several changes which seem to line up temporally with molecular clock estimates for a polypoidal hybridization event where the lobe finned fish genome in the tetrapod ancestor was effectively duplicated. Unfortunately I was only able to access that paper on campus via my University journal subscription so it would be hard to find again. Point is from what I have read the predator escape hypothesis doesn't seem very likely if they lack the skeletal and muscular strength to actually move or support their weight at all on land. Those papers seem to argue for a aquatic walking scenario with the terrestrial switch happening around the time of the full genome duplication event which seems to align with the Devonian extinction events. I'm not sure we can say what or why but it does seem plausible that tetrapods might not have been able to go on land without an evolutionary fluke.

That makes sense considering most of the ones that couldnt make it back to the water died haha.

@@Dragrath1 The more recent information about Parmastega backs up the idea of water-walking tetrapods long before anything vertabrate actually got out of the water. It was a mostly cartilaginous tetrapod from earlier than tiktaalik; it was shore-dwelling instead of the later freshwater tetrapods, and it appears to have been an evolutionary dead end, but one which lived quite well for a while. It couldn't get out of the water, but it walked around in the shallows gathering washed up food just fine.

Exactly what I was thinking, you only need those in the middle. Kind of like how horses and many other hoofed animals lost their digits.

@@taxidermiedhuman1523 fewer digits means more tensile strength per digit. Highly evolved diggers also lose digits in their hands

I guess when it comes to land bound locomotion, fewer is better.

Agreed. I would think being on land requires thicker stronger bones, so it may have been a fair tradeoff to make fewer but stronger bones.

Nah, they just kept getting messed up when they tried to count things. Eventually, they were simply unable to fall asleep while tending their sheep herds, and thus died out.

Australians, always gotta be different.

I don't remember lizards with 4 fingers...

Ah, and also brilliant swimmers - perhaps there's some heft to the "' motion "on land" vs "in water" theory '"? Maybe given enough time, Aligators might gain a sixth digit? :')

@@OddcessiveNooBurrito Now, I wonder if the terrestrial part of crocodilian life still plays too much of an important role for that to happen though.... Perhaps the cetaceans will gain extra digits spontaneously over time?

@@OddcessiveNooBurrito It might just be that they had not evolved enough dexterity for more fingers to be redundent.

Moles also have an extra finger.

cool. nice way to nerd.

I’ve gone down some pretty random rabbit holes doing that too.

@@patsysadowski1546 this is the internet not field of cuddly bunnies

​@@kyptos2252same thing if you squint

Koalas basically have two thumbs on each hand.

I think it is because our ancestors started using and or making tools more and more

What come first Male or female

@@ezpeasy3967 the egg the chicken no wait I know what they're going to say they're going to try to tell you both like a hermaphrodite. Then they're going to say stop assuming genders. Then after that they are going to tell you stop using those terms male and female because it has the word male in it, then after that they're going to say don't use man or woman because woman has the word man in it.

Looking at some of those tetrapods, It looks like digits were developed to help scoop at the ground and propel themselves forward on swampy land. So, the digits that are there are facing forward, and if you tried to fit 13 digits on a single hand, each digit/finger would have to be so thin to fit, and may be prone to breaking. So, thicker fingers are needed to support the weight, and trying to fit thicker digits on yhe front of the palm, meant you're maxed put at 4 or 5. Thats my best guess :-)

Or in Hexadecimal

There's actually a school house rock that's kinda about that

Base 14 is not inherently worse than base 10, given 14 has the exact same amount of factors (1,2,7,14). Base 12, on the other had, has many more (1,2,3,4,6,12)

@@sohopedeco yup! but we're just used to a base 10 numbering system so we can kost easily go in forms of 10 (10,20,30,40 etc) where their numbering system would likely be different to compensate if that makes any sense? (sorry if this is slightly off context)

@@l.zevicreations 12 would just be the next ten and would be easy just for whoever uses it just as 10 is for us

I guess if our common ancestor had four fingers, we would be like people from The Simpsons.

mmmm no.

I mean some people do have more then five fingers, people who have Polydactyly.

I don't know about that but I believe the polydactyl mutation is dominant in human heredity.

@@justforplaylists Yeah it would have had to have evolved all the reptile like traits independently I would instead based on the abundance of oddities in the Triassic be more willing to bet it might have been a polypoidal hybrid organism since all 4 of the polypoidal hybridization events recorded in the amniotic genome happen to line up with a major mass extinction event and stressed conditions in modern times have been linked to increased likelihood of polypoidal offspring being born. Its possible with two copies of the developmental genes that the expression of them could then be split to allow one copy to take over the brain and spinal functionalities and the other to take over limb development avoiding the deformities that tend to occur alongside digit duplication events. Or maybe some other gene or mutation countered those detrimental factors to make it ecologically viable to increase the number of digits?

If I could quadruple flip someone off, I would be so happy

Typing like a boss, I bet.

The Digital Era?

Better keyboard and gaming input

@@ASLUHLUHCE Play the F Chord on a guitar like a boss.

this is the problem with schooling.. if this interest you then you have an interest in biology but the class and test scoring system prevents student from simply enjoying new information for the sake of learning

Do you have a twitter?

There's also a dog breed that at its height was very polydactyl. Can't remember the name of it, but they used it to hunt puffins.

@@SupersuMC Norsk Lundehund

Somewhere, Blake just let out a scream while thinking of coconut crabs.

That's what make crabs so unusual

There's a clause in that hypothesis: "except crabs, of course. Dang crabs."

Octal. Base 8 is octal.

@@AndrewTBP but we would have 16 fingers total, so hexadecimal.

Ye

I thought polydactyly was actually a dominant trait

@@alinaowen2635 I believe there are multiple variants. The Amish one, for example, is recessive iirc

I read its dominant.

Yeah, what about Hemingway's cats?

I only hear about it in cats and when they said 5 or less I was like what about cats

It's quite common in cats. They seem to do just fine and have no obvious problems.

Our polydactyl cat was the clumsiest cat I've ever known. He did have a couple health problems including something with the nerves in his back/back legs as he aged, no idea if it was related at all to the mitten feet

It happens in humans too, actually. ^^'

Eyes have evolved many times. Be more specific. Cephalopod eyes, arthropod eyes, vertebrate eyes, which?

Many years ago, I went on a tour of the prehistoric caves in France, and I very surprised to see the number of hand paintings that had six fingers -- the only people I know who have polydactyly are me and members of my family. Interestingly enough, polydactyly is a dominant trait on humans. Even with early intervention (removal of the sixth digit to ensure better hand development as the sixth finger relies heavily upon the fifth finger), polydactyly is becoming an oddity of genetics, much like left-handedness (which hovers at 10-12% globally -- BECAUSE SCISSORS ARE A DEATH TRAP FOR THE SOUTHPAW!!!).

This would be so interesting!

I also want these topics in upcoming videos.

Whales seem to have totally lost their teeth before they evolved baleen (and baleen doesn't derive from the same tissue as teeth), probably they were suction feeding for a while

Early land living cetaceans like Pakicetus didn't have hooves like a deer etc, even though it was an artiodactyl. But we see that with some other living ungulates, e.g. rhinos don't have hooves in the way deer do.

Pretty sure they have an episode called “when whales walked”

Saw something on that. They generally have it better, if the extra digit is controllable.

Is the extra finger usable though?

Hard to say. The Babylonians and the Phoenicians used a base 12 system despite only having 10 fingers.

@@erraticonteuse i thought it was base 360.

We would simply be using a different base system

@@tompatterson1548 OK Google says that it was actually base 60, which is also divisible by both 12 and 10. However the Egyptians did use base 12.

So, short answer, no. We’ve settled on base 10 for arithmetic, but mathematics is much larger than your base system and arithmetic.

How does one "do" spec evo?

@@MM-jf1me Making diagrams, art, and flowcharts for fictional evolutionary lineages.

Agreeeee

That’s rare, so it’s not being included.

It's a mutation, not a trait of the species

@@KellyClowers a mutation that keeps appearing in cats that are not directly related. Not to mention mutation is part of evolution.

It’s a developmental anomaly.

@@phantomreaver85 still not a trait of the species. If six toed cats end up displacing 5 toed as the vast majority of the population, then we could talk

Genes can have lots of funny names.

maybe even include Iberospinus!

They’ve done spinosaurs already.

Because of the sun exposure. Some places it is more than others so thousands of years the melatonin changes to suit the environment.

Given cicadas, I wouldn't assume the insects were quiet in the Devonian. Modern insects make noise with assorted body parts that we didn't always recognize as noisemakers until fairly recently (e.g., how crickets chirp).

@@Eloraurora Oh true, I had honestly forgotten about cicadas and crickets...neither of those appear until the Triassic, but I suppose it's possible their predecessors could have made sounds.

"Pandas have 6 digits. Surely it would have taken 5 seconds to fact check "no species of vertebrates have more than 5 digits"?" - oh, I love pathetic irony; surely it would have taken 5 seconds to fact check 'pandas don't have 6 digits'!!! THINK YOUR OWN SPLUTTERINGS THROUGH! ------ Ok, that's my justified annoyance out of the way; - the 6th appendage is NOT a digit, it's an enlarged adaptation to diet. A sesamoid bone growth. Nor is the opposing appendage, the pisiform sesamoid a digit either

​@@Dr.Ian-Plect Did you even google this yourself? Try googling, "do pandas have 5 digits?". The legit first thing that comes up is "pandas have 6 digits" for me.

Not necessarily, at least for non-cursorial (running vertebrates). The multiple fingers of climbing vertebrates like primates serve that locomotory purpose very well. Now for the scenario you imagined, while it _could_ be possible to re-evolve multiple metacarpal/metatarsal and phalanges bones, it's also possible that other bones like the carpals and tarsals (wrist and ankles respectively) would then be used to take over this function. Something like the "extra" thumb of giant pandas which is actually a modified wrist bone.

Species that relied on them would keep them. A squirrel would have a hard time climbing without them. But the evolutionary pressure for fewer digits keeps them from proliferating pointlessly

• our ancestors used to have six or more digits per hand; then [cut to scene of kitten chewing on a hand] • "Cats are known for throwing up." oh, there's more to that sentence.

They probably wouldn’t be a high enough cost for it to be a selective pressure. It’s an interesting hypothesis tho!

I recall some mathematical models I stumbled across a few years ago coming to the conclusion that between five and six was the lowest energy solution, and in that case, you're probably best rounding down. Take that with a grain of salt though: it was a few years ago, and I can't pull up any references.

that's a mutation not a trait of the species

It’s a developmental anomaly.

@Catarina Barbosa It's all mutations really, everything. There are entire families of people with 6 fingers on each hand. There is a breed of dog that have an extra digit on the back feet, there are cats who naturally have bigger paws with extra digits who live in snowy areas. All of these examples are lineages that are being carried through generations.