It's also interesting that despite being primarily symmetrical we and other animals have organs that aren't. For example our hearts are only on our left side, our livers on the rights, and the digestive tract is kind of all over the place. It seems that the evolutionary pressure towards symmetry mostly applies to our outside structure and sensory organs.
Yup. Binocular vision helps with depth perception, two ears make it easier to get the directions sounds come from, two nostrils.... in case one get clogged?
I think it is also because most compact organisation is preferred. If you think about it, there is no space left for nothing. Everything is occupied by organs, muscels, bones, blood vessles, and fat reservoirs. There isn't any space which is just filled by "flesh". And since some organs do not need to appear two times, like two hearts would be hindering each other, it seems like they were sorted in the most compact way.
Well I guess it would be weird if your stomach had an urge to schlop around the ground and find food. If you're only a part of an organism, you don't have the burden to survive and evolve by your own means esp by selective pressures from other niches.
@@ninanando I got a feeling that any matter has "sight" after meditation. Not like humans, it just registers everything like a CCTV. It was just an intuition, and gone
They aren’t symmetrical, they have matching general outer components, bilaterally. In detail the sides are not symmetrical, and their asymmetry have separate functions both in use and display.
The answer is simple, it allowed for weight balance, and movement is a lot easier when you aren’t having to counterbalance a large weight on one side while having far less on the other. You would just end up falling over repeatedly which isn’t good when you are trying to move in a singular direction.
Yes, but what still really surprizes me is just how symetrical we are in detail. I find it hard to imagine that a left ear 5 centimeters below the right ear would be different enough from 2 ears at equal height to actually make a big enough difference in our (and other animals) chances of survival. Or that we dont have 2 left, or 2 right hands. Or 4 fingers on the right and 5 on the left, etc. I'd like to see an explanation for that.
I just want to show my appreciation for your video. I was baked and sitting on the couch and thought "why are animals symmetrical" and was delighted to find such a great answer so quickly. thank you
@@michaeljordan4457 Ferns and Cacti? Almost all plants seem to be fractals, repeating smaller versions of themselves to grow and reproduce Edit; You could even argue the entire universe is a fractal and we live in a simulation that uses nothing but numbers to fool everyone, Matrix style?
@@cesarcueto1995 Ah, however these things you call alive are very certainly made of things that are not. Even the very chemical process that run these fleshy machines are structured in ways that, when placed in an optimal environment, can form crystals and structures akin to the most perfect of computer models.
I swear, I wrote a paper that basically turned into 'why bilateral symmetry works' for my 1st year college Astronomy class back in 1992, (when they foolishly let us pick from a term paper topic list that included "describe the hypothetical evolution of life on another planet" and I am so thrilled to watch this video, because I came to similar realizattions and understandings and this video feels SO VALIDATING for that paper. Thank you! 🙂
@@fkhan2006 It was 30+ years ago, but as I recall it was more focused on sapient life evolution, so the various alternate symmetries and asymmetries were just touched on as what had advantages over the others in passing. Not all life on earth has a symmetry let alone bilateral symmetry. Life evolves to be successful at thriving in its niche, and not all niches have the same traits that provide an advantage. 🤷♀
Whenever I’m articulating a skeleton, this is always super helpful! If I have a bone that I can’t place, I check if it’s symmetrical; if it is, it’ll go somewhere in the middle, and if not, there will be a matching one somewhere!
Flatfish are still born symmetrical though, right? Their right eye migrates through their body to the other side when they mature. It's almost like a mini evolution at super speed.
Last Christmas, I had an inflamation on my jaw joint. My mouth was all crooked like that bird and I couldn't eat anything without feeling a lot of pain.
This is something that I would have never realized even though it's so obvious: that most animals are bilateral (and all the advantages that this brings along). It's because of things like these that I love this channel.❤️
Interestingly while it wasn't mentioned there is actually a group of cnidarians the anthozoans which have convergently evolved a bilateral axis. In the early development of both bilaterian and Anthozoan embryos this occurs by using a second Hox gene cluster(which seems to in both cases arisen by duplication of the original Hox gene cluster inherited from the last common ancestor of bilaterians and cnidarians that granted them their preferential axis of radial organisms) and using that second copy of the body orienting HOX gene clusters to form a second body axis perpendicular to the first resulting in a bilateral organism
Same! It never occurred to me that normal animals could be anything but bilateral. It was never explained this way to me before, and now I feel bad for thinking things like anemones weren't "real animals". They just have a spread-out nervous system!
Really glad that you're covering this, becuase I remember wanting to learn a short explanation of this, because the things that go that far back for life are usually not necessarily intuitive.
@@quartzking3997 I know but it's cementing itself more and more as time goes on. I'd actually rank this higher than PBS Eons which is also a great channel. edit: And Ben G Thomas
This and the Ben G. Thomas channel are my favorites, though I have to say this is one may be edging them out in terms of these in depth videos about niche topics
I had this exact question on my mind earlier today and didn't look it up for some reason, and now I got this video recommended on the home page. TH-cam scares me sometimes 😐 Nice video btw :3
Today I was thinking about watching "the rock" rap. I knew it existed months ago but forgot. Only today I thought I should watch it so open the app and what do you know the first video was "the rock" rap part 1 hour version. ☠️
i love your videos, they’re so good. they’re just much less “hand-wavey” than other science channels, you just let these interesting topics speak for themselves instead of trying to hype them up.
This is one of the only channels that I wish I could give more than one like to on all the videos. The content is just so good I want to make the SEO to promote the videos more, so more people can discover this channel
@@voopsin8116 my doctor told me one of my thighs is longer than the other, i dont know about this person but for me its completely normal and it always has been, i didnt even know about it until my doc told me
Great video, thank you. Your delivery is very calm, there's no jumpy music, and the visuals are clear and interesting. I just read that some types of snakes have lungs that aren't bilateral - to fit their body shape, they have one large lung and one very small one, located one in front of the other - thought that was pretty cool. (editing - I see some other commenters pointed out the snake stuff)
This makes me think that most animal-like aliens will be bilateral as well. Gravity and centralised nervous systems aren't things exclusive to Earth, so we'd expect that any other planet, which can hold life, will hold bilateral life.
The problem with all this type of speculation is we simply have no idea how typical life and evolution on earth is. Life itself has only emerged once that we know of, and it’s entirely possibly that we are not at all normal in terms of other life forms in the universe.
@@HkFinn83 What we know for certain is that every planet has gravity. And as bilaterally is the most effective way of balancing an organism in gravity, we'd expect they'd also do the same. It's not blind speculation. Organisms exposed to the same conditions develop the same structures regardless of their relations - wings, for instance, developed in bugs, birds, and bats, all independently.
@@wachyfanning Bilateral definitely would be a common trait, but in theory, we could also see radial symmetry occur. Imagine for example, a circular creature with legs all around it, akin to a circular centipede. It genuinely could live and survive. Considering evolution isn't based on what's best and instead is on what works, if there was no pressure on that animal to change, it wouldn't. On Earth, radially symmetric animals never evolved far enough to develop traits that would've allowed them to survive on land (even if it's just breach and stay on the surface for a bit), but that doesn't mean the story is universal.
@@wachyfanning Wings also developed in pterodactyls, a group of extinct dinosaurs. Although modern birds also evolved from dinosaurs (and many scientists consider them to actually be dinosaurs), pterodactyls were not ancestors of birds.
most radial symmetric animals have something in common that I noticed, and it's that their mouth tends to be in the center of their body, such as starfish and octopus
@@dewinmoonl Another common point of similarity is that both echinoderms and cnidarians require a solid substrate to attach to during their embryonic development. There is also fossil evidence that early comb jellies similarly evolved from sessile organisms so it seems that radial symmetry is likely useful for a sessile or fixed in place organism. Of course embryonic studies show that in the two lineages that have convergently evolved bilateral symmetry Bilaterians & Anthozoan cnidarians(i.e. anemones &corals which primarily exhibit bilateral symmetry in their extended larval planula stage though there is a slight preferential bias remaining in their adult forms) did so by duplicating the genes that encoded the original preferential axis radial organisms have.
@@dewinmoonl in order for them to be radially symmetrical, they would need their mouth to be central. Otherwise the mouth would throw off the symmetry.
Curious about Octpi... They are partially radially symmetrical (in their arms) but also partially bilaterally symmetrical (in their head.) They are part of the bilateral group but it is interesting they evolved this way.
It's so interesting how you get a question in your head, solve it, and share it with others I never really acknowledged the symmetry in organisms, now it's super interesting to me
that was truly educating, loved it. Made me understand the way we look at the world on a deeper even philosophical level. I think the way how our bodies are build, with a front and back and a center of nerves (brains), must have had an influence on how we think and view the world, how we developed a philosophy of "right" and "wrong", of "forward" and "backward", of truth itself.
The idea that direction is just so advantageous that it produced the variability we have today is so fascinating. I think it also wouldve been interesting to address dominant sides, like how most of our species favors our right hand, how that might manifest in other species, etc.
Very Interesting! i didn't know starfish where technically bilaterians, i wonder if their madreporite(at least the ones that only have one) give any clues as to their real orientation.
The interesting thing is they start out bilateral in the larval state and turn radial as the grow up, adding extra arms. Interesting to know why would this happen. What is the advantage?
@@Fazzel It’s possible that all echinoderms evolved from a species in a genetic bottleneck, and that it had relatives that may have lacked radial symmetry.
So, low gravity environments could sustain land animals with radial symmetry? I imagine something as alien as a flying jellyfish. Sounds cool, but might not be feasible, since it seems way harder to have non deliberate movement on air.
Wouldn't flying jellyfish require a very dense atmosphere in order to pull off that trick? At least it seems so to me, but in order to have ah dense atmosphere, the planet itself would have to have a very strong gravitational field as well, so i think your point is somewhat moot. Sorry to be such a partypooper. 😢
It should be noted that radial symmetry on Earth appears to have been a prerequisite for bilateral symmetry. Specifically radial symmetry requires one body orienting axis, but bilateral symmetry requires two body axes the second axis being perpendicular to the first resulting in a defined top and bottom for organ development. In both bilaterians and Anthozoan cnidarians, bilateral symmetry was evolved thanks to gene duplication copying the original HOX gene cluster that made their first body axis possible. Anthozoan cnidarians bilateral symmetry is harder to observe as it's mainly expressed in their larval planula stage but they do apparently retain a degree of a preferential direction even as mature polyps not unlike Echinoderms
@@BertGrink -- Venus is somewhat smaller than the Earth yet has a vastly denser atmosphere, the pressure is about 90 times as high as at sea level on Earth. Saturn's moon Titan is not much bigger than the Moon, and yet has an atmospheric pressure 50% higher than the Earth. So a planet like a cool Venus or warm Titan could allow airborne jellyfish.
Thanks, this will really help drawing aliens. Something as simple as shifting how they are symmetrical is both sensible and something I'd never really considered.
It is videos like these make me so intrigued by what potential alien life forms could look like. Something as simple as their gravity being less powerful than ours could result in body structures we cant even fathom.
@@morganirosonna2871 --- Is kind of interesting. Two lungs, two kidneys, but only one stomach, one heart. Yet we can survive with just one lung or one kidney. How much better off would we be with two hearts? Probably a lot less people would die from a heart attack. In a way the digestive track is just a long tube that is basically just folded up to fit into the body cavity so if it were stretched out in some ways it would be bilateral. The large intestine is somewhat bilateral. Also the stomach to some extent, just turned sideways.
@@dewinmoonl definitely not plants. Corals are animals and rangeomorphs are believed to be stem animals. I guess scientifically illiterate people will call them plants, as they might call dolphins fish, or call bats birds, still not correct.
@@pansepot1490 corals are pretty plant like, in that they filter their surrounding for nutrients and photosynthesize with internal algaes. i was just making an analogy of convergent evolution to make a point that those funky designs exhibited by earlier animals are also the same design that made plants and corals, aka convergent evolution. I'm not scientifically illiterate haha I studied biology as undergrad so I'm well aware that corals are not plants, those earlier animals are not plants, and dolphins are not fish, and bats are not birds, you name it.
Somehow, I lost all my youtube data including all the channels I was subscribed to. Moth light was one if the first I could remember and search to resubscribe to. I wonder why? 😉
Fun fact: Did you know that in some species of Owls, the left and right ear holes are located at different elevations on their skull? The more you know.
Is that to make each ear specially better at picking up vibrations from certain angles whilst using the information to create an "image" of its surroundings?
@@strrawberrytekken3698 With the face of Owls being shaped like radar dishes, yes. Most importantly having the ear holes located at different elevations allow them to pinpoint where exactly a noise is coming from on a vertical plane.
@@TyrannoKoenigsegg yeah you're right! lol. We have consciousness, and therefor know of our own mortality. This is what I think pushed people towards religion or other definitions of their existence for justification. Why do humans need a reason for existing?; Perhaps it is by random circumstance. We just happened to survive more efficiently through evolution by random mutation. Now we have big brains and don't know why, I believe in the sentiment that, "We are the universe experiencing itself".
This documentary is just so good. A hundred times better than 4 minute-long badly researched documentary about the golden eagle with pictures from bald eagles, peregrines and even buzzards.
interesting that even a lot of plants exhibit bilateral symmetry too , generally they aren't entirely bisymmetrical but parts of them are , almost every leaf , fern frond and many flowers are also bilaterally symmetrical
8:05 this adaptation is not entirely unique, in fact, most male hominids species have much larger wrists and forearms on their right sides rather than left; in order to compensate for their lack of sexual activity. 😂
@@howielowis458 Nontheism has generally been used to describe apathy or silence towards the subject of God and differs from atheism. Nontheism does not necessarily describe atheism or disbelief in God; it has been used as an umbrella term for summarizing various distinct and even mutually exclusive positions, such as agnosticism, ignosticism, ietsism, skepticism, pantheism, atheism, strong or positive atheism, implicit atheism, and apatheism. From Wikipedia
Basically, a nontheist is apathetical towards a god existing. They could also include any group that isnt a theist. An athiest is in direct opposition to a god existing An agnostic believes one may or may not exist, and has put thought into the subject. A deist believe a god can be discovered through the worlds knowledge And theism is the belief a god or gods exist
I think it's important to note that literally most animals, including almost all of the obscure ones, are bilaterians. The charts in this video kind of made it look like there were only a few animal groups under Bilateria, but in reality, it's more like there are only a few groups outside of it, at least among extant animals. Those are: Porifera, Cnidaria, Placozoa, and Ctenophora. That's it. All other animals are bilateral. In fact, aside from Placozoa, I would argue none of these are obscure. Sponges, stinging tentacle animals, and comb jellies are the other three. And very few animals in those groups, aside from Placozoa, are microscopic. All other microscopic animals are bilateral. Tardigrades, rotifers, etc. are all bilateral. So yeah, I like what you said about evolution during this video, but I think the way you approached taxonomy was pretty misleading.
Comment section in a nutshell: 40% funny comments 30% questions that were answer in the video 20% actual questions brought up by the video 9% false corrections 1% lol evolution is fake
And those "evolution is fake" comments are here just because they are so fascinated and can't look away but feel obligated to respond "fake fake fake!"
Evolution is fake. Its been Proven that mutations dont occur like darwin suggested. For example, a dog will never grow gills like a fish, or wings like a bird Because all animal's genomic strictures have limits. In other words they dont have the "Genes" to gain these things. Anyways whatever.
It's also interesting that despite being primarily symmetrical we and other animals have organs that aren't. For example our hearts are only on our left side, our livers on the rights, and the digestive tract is kind of all over the place. It seems that the evolutionary pressure towards symmetry mostly applies to our outside structure and sensory organs.
yeah, there's no selective pressure for heart on left vs right, but there is if your left leg is bigger than your right: you'll get eaten.
Yup. Binocular vision helps with depth perception, two ears make it easier to get the directions sounds come from, two nostrils.... in case one get clogged?
@@pansepot1490 Two nostrils help to smell directionally for a bunch of animals. We just decided smelling is for suckers.
I think it is also because most compact organisation is preferred. If you think about it, there is no space left for nothing. Everything is occupied by organs, muscels, bones, blood vessles, and fat reservoirs. There isn't any space which is just filled by "flesh". And since some organs do not need to appear two times, like two hearts would be hindering each other, it seems like they were sorted in the most compact way.
Well I guess it would be weird if your stomach had an urge to schlop around the ground and find food. If you're only a part of an organism, you don't have the burden to survive and evolve by your own means esp by selective pressures from other niches.
this is such a fundamental thing i never thought about.
Same
Tényleg igen
I took acid and now I can’t stop thinking about it
@@johnnyshanahan2185 it becomes so scary just staring at a creature staring back at you
@@ninanando I got a feeling that any matter has "sight" after meditation. Not like humans, it just registers everything like a CCTV. It was just an intuition, and gone
I wish all my bilaterally symmetrical relatives a very pleasant evening.
They aren’t symmetrical, they have matching general outer components, bilaterally. In detail the sides are not symmetrical, and their asymmetry have separate functions both in use and display.
No crib b by ki donc g finding je
Sorry i am not symmetrical
all my homies are bilaterally symmetrical
I appreciate you
The answer is simple, it allowed for weight balance, and movement is a lot easier when you aren’t having to counterbalance a large weight on one side while having far less on the other. You would just end up falling over repeatedly which isn’t good when you are trying to move in a singular direction.
That’s all I need to hear.
Yes, but what still really surprizes me is just how symetrical we are in detail. I find it hard to imagine that a left ear 5 centimeters below the right ear would be different enough from 2 ears at equal height to actually make a big enough difference in our (and other animals) chances of survival. Or that we dont have 2 left, or 2 right hands. Or 4 fingers on the right and 5 on the left, etc. I'd like to see an explanation for that.
Said the fiddler crab...
@@smilloww2095 just look up punnet squares
@@smilloww2095 Owls lmao
I just want to show my appreciation for your video. I was baked and sitting on the couch and thought "why are animals symmetrical" and was delighted to find such a great answer so quickly. thank you
Hahaha I love your comment
Yo same
Same bro
I like to make insects unsymmetrical
Also watching this baked
To be clear - there's tons and tons of organisms that grow in fractals nowadays. They just are all plants. (ex, broccoli and cauliflower)
Rangeomorphs are thought to be animals so I think it's implied that he meant there are no extant fractal animals.
Broccoli and cauliflower are the same plant, so perhaps more varied examples?
@@michaeljordan4457 Ferns and Cacti? Almost all plants seem to be fractals, repeating smaller versions of themselves to grow and reproduce
Edit; You could even argue the entire universe is a fractal and we live in a simulation that uses nothing but numbers to fool everyone, Matrix style?
@@_NEPO_ but the universe isn't alive. It's not an organism so it's irrelevant
@@cesarcueto1995 Ah, however these things you call alive are very certainly made of things that are not. Even the very chemical process that run these fleshy machines are structured in ways that, when placed in an optimal environment, can form crystals and structures akin to the most perfect of computer models.
I was wondering about starfish, but you fortunately addressed that.
still weird we’re more related to it than ants or snails
Seconded. "But what about starfish... Oh."
Star fish is still symmetrical
Same
Flounder
"Bilaterians have a clear direction of movement"
Crabs: "And I took that personally"
But crabs can walk forward and every other direction too
@@darkaliebaba99 not rarely
lol
@OG MXBC that's what I came to say lol
The ones wit one big claw, did not
I swear, I wrote a paper that basically turned into 'why bilateral symmetry works' for my 1st year college Astronomy class back in 1992, (when they foolishly let us pick from a term paper topic list that included "describe the hypothetical evolution of life on another planet" and I am so thrilled to watch this video, because I came to similar realizattions and understandings and this video feels SO VALIDATING for that paper. Thank you! 🙂
that's really cool. so I'm assuming you argued that alien animals would also be symmetrical?
@@fkhan2006 It was 30+ years ago, but as I recall it was more focused on sapient life evolution, so the various alternate symmetries and asymmetries were just touched on as what had advantages over the others in passing. Not all life on earth has a symmetry let alone bilateral symmetry. Life evolves to be successful at thriving in its niche, and not all niches have the same traits that provide an advantage. 🤷♀
Whenever I’m articulating a skeleton, this is always super helpful! If I have a bone that I can’t place, I check if it’s symmetrical; if it is, it’ll go somewhere in the middle, and if not, there will be a matching one somewhere!
can make it a nightmare to side the bones though if you don't have the corresponding match - fibia are such a pain!
Yes! I’m currently working on a buzzard and the ribs are a nightmare, considering i’m missing a few!
I thought you meant a real life skeleton and got a bit worried
@@kingpotato7183 I do, many! Not human though😅 Specifically working on articulating a Buzzard skeleton atm!
Flatfish are still born symmetrical though, right?
Their right eye migrates through their body to the other side when they mature.
It's almost like a mini evolution at super speed.
yes, they are born symmetrical
That’s kinda gross and kinda cool at the same time 😶
maybe if ur thinking of pokemon evolution lol
More like development. It's the same idea with humans in that we are embryos which develop into a bipedal organ sack
@@powfoot4946 not to mention we lose our tails during embryonic development
Imagine a jellyfish with a brain. Now, don't ever imagine that again.
@@Wikispedia wat
I mean jellyfish do have a ring composed of neurons that’s basically a brain. It’s just fairly simple and not that sophisticated.
@@Meejie I'm talking human brains.
an octopus ?
King jelly
The picture of that crossbesk bird hurts my teeth
Last Christmas, I had an inflamation on my jaw joint. My mouth was all crooked like that bird and I couldn't eat anything without feeling a lot of pain.
My teeth are worse than that bird.
@@sohopedeco I guess you should've tried pinecones! Glad you got better =)
same, it makes my jaw feel awkward
7:36
Every frustrated artist has asked themselves this once when drawing a face.
I’m blown away by your production, it’s simple, VERY factual and elegantly presented. Can’t wait to watch more of this content. Subscriber earned 🎉😅
This is something that I would have never realized even though it's so obvious: that most animals are bilateral (and all the advantages that this brings along).
It's because of things like these that I love this channel.❤️
Interestingly while it wasn't mentioned there is actually a group of cnidarians the anthozoans which have convergently evolved a bilateral axis. In the early development of both bilaterian and Anthozoan embryos this occurs by using a second Hox gene cluster(which seems to in both cases arisen by duplication of the original Hox gene cluster inherited from the last common ancestor of bilaterians and cnidarians that granted them their preferential axis of radial organisms) and using that second copy of the body orienting HOX gene clusters to form a second body axis perpendicular to the first resulting in a bilateral organism
@@Dragrath1 amazing! Thanks!
Same! It never occurred to me that normal animals could be anything but bilateral. It was never explained this way to me before, and now I feel bad for thinking things like anemones weren't "real animals". They just have a spread-out nervous system!
Huh, I never knew echinoderms were bilatarians (which autocorrect wants to render as “BiL Atari and”). You learn something new every day.
Autocorrect is a curse when writing anything scientific or specialized.
@@pansepot1490 The horror of every german student in biology is autocorrect constantly changing DNA to 'DANN' (eng: 'then') when writing a protocol
Anyway isn't bilatEral?
Just wait till you try to talk about they multi purpose anus’s without autocorrect.
Only if you try.
It’s weird that I never wondered this thanks for opening my mind I’m gonna be stuck on this topic for a while 😅🧐
Spacekid Productions same
Fr
My mind has refused to go back to work also. 😄
I'm stuck on Pineapple Rag. ♪♪
it's cause symmetry is so inherent in your thought process
The red fish at 9:07 is like: who are you filming? Are you filming me? No? Ok let me just get out of your way then.
I study left-right symmetry breaking in the embryo for my PhD so this video is extra fascinating.
Really glad that you're covering this, becuase I remember wanting to learn a short explanation of this, because the things that go that far back for life are usually not necessarily intuitive.
I'm really glad when I was told that nothing IS symmet.
This is shaping up to be a top quality channel on this subject
Always has been
@@quartzking3997 I know but it's cementing itself more and more as time goes on. I'd actually rank this higher than PBS Eons which is also a great channel.
edit: And Ben G Thomas
This and the Ben G. Thomas channel are my favorites, though I have to say this is one may be edging them out in terms of these in depth videos about niche topics
@@kevinwells9751 Yeah forgot Ben G Thomas, also a great channel my bad.
Flounder in development
Symmetry: "Imma head out.."
Flounder halibut and fluke are bilateral free swimming fish when they're young.
Dave Glines didnt get it, but this was the first thing in my mind.
I still don't. Well maybe. Nah.
yeah thats what i thought
Exactly what I was thinking!
I don’t even like science that much but I found this so interesting and enjoyable
That means you like science
I had this exact question on my mind earlier today and didn't look it up for some reason, and now I got this video recommended on the home page. TH-cam scares me sometimes 😐
Nice video btw :3
Today I was thinking about watching "the rock" rap. I knew it existed months ago but forgot. Only today I thought I should watch it so open the app and what do you know the first video was "the rock" rap part 1 hour version. ☠️
i love your videos, they’re so good. they’re just much less “hand-wavey” than other science channels, you just let these interesting topics speak for themselves instead of trying to hype them up.
This is one of the only channels that I wish I could give more than one like to on all the videos. The content is just so good I want to make the SEO to promote the videos more, so more people can discover this channel
Like all the comments
Heres me with a crooked nose, lazy eye and one leg longer than the other 💪
@@voopsin8116 my doctor told me one of my thighs is longer than the other, i dont know about this person but for me its completely normal and it always has been, i didnt even know about it until my doc told me
We all have a limb that is longer than another, it's not completely the same, though the difference is very small for an average hunan
we humans have stop natural selection,
You should find a partner with similar traits and starts a new species
@@lancebianzon6034 no?
the narrator’s voice is so calming, it is a really relaxing video
Great video, thank you. Your delivery is very calm, there's no jumpy music, and the visuals are clear and interesting.
I just read that some types of snakes have lungs that aren't bilateral - to fit their body shape, they have one large lung and one very small one, located one in front of the other - thought that was pretty cool.
(editing - I see some other commenters pointed out the snake stuff)
I envy them, I am an ugly asymmetrical freak.
Me too. Evolution is against us procreating, which I suppose is a good thing for the species in the long term.
@@JohnyG29 People say humans defeated natural selection... we are the living proof than they are wrong lol
How asymmetrical? My left jaw is slightly bigger than the right.
Bruh is u a Denisovan or a Neanderthal :0
@@JohnyG29 : Allahu Akbar! 10
This makes me think that most animal-like aliens will be bilateral as well. Gravity and centralised nervous systems aren't things exclusive to Earth, so we'd expect that any other planet, which can hold life, will hold bilateral life.
Baka
The problem with all this type of speculation is we simply have no idea how typical life and evolution on earth is. Life itself has only emerged once that we know of, and it’s entirely possibly that we are not at all normal in terms of other life forms in the universe.
@@HkFinn83 What we know for certain is that every planet has gravity. And as bilaterally is the most effective way of balancing an organism in gravity, we'd expect they'd also do the same. It's not blind speculation. Organisms exposed to the same conditions develop the same structures regardless of their relations - wings, for instance, developed in bugs, birds, and bats, all independently.
@@wachyfanning Bilateral definitely would be a common trait, but in theory, we could also see radial symmetry occur. Imagine for example, a circular creature with legs all around it, akin to a circular centipede. It genuinely could live and survive. Considering evolution isn't based on what's best and instead is on what works, if there was no pressure on that animal to change, it wouldn't. On Earth, radially symmetric animals never evolved far enough to develop traits that would've allowed them to survive on land (even if it's just breach and stay on the surface for a bit), but that doesn't mean the story is universal.
@@wachyfanning Wings also developed in pterodactyls, a group of extinct dinosaurs. Although modern birds also evolved from dinosaurs (and many scientists consider them to actually be dinosaurs), pterodactyls were not ancestors of birds.
Can you do a video on starfish and how they evolved away from bilateral symmetry? That’s an interesting exception to the other bilateral animals.
most radial symmetric animals have something in common that I noticed, and it's that their mouth tends to be in the center of their body, such as starfish and octopus
@@dewinmoonl Another common point of similarity is that both echinoderms and cnidarians require a solid substrate to attach to during their embryonic development. There is also fossil evidence that early comb jellies similarly evolved from sessile organisms so it seems that radial symmetry is likely useful for a sessile or fixed in place organism.
Of course embryonic studies show that in the two lineages that have convergently evolved bilateral symmetry Bilaterians & Anthozoan cnidarians(i.e. anemones &corals which primarily exhibit bilateral symmetry in their extended larval planula stage though there is a slight preferential bias remaining in their adult forms) did so by duplicating the genes that encoded the original preferential axis radial organisms have.
@@dewinmoonl in order for them to be radially symmetrical, they would need their mouth to be central. Otherwise the mouth would throw off the symmetry.
@@dewinmoonl
Octopus are not radially symmetric. They’re still bilateral. I understand your point though
Best channel on TH-cam!!! You should get a documentary award from someone. Love your vids!!
Both of your videos I've just watched dropped my jaw. Thank you for some excitement in sharing them and whatever is ahead.
6:17 showing the crab at this moment is interesting since they are very assymmetric around the direction of motion! Thanks for the video
Curious about Octpi... They are partially radially symmetrical (in their arms) but also partially bilaterally symmetrical (in their head.) They are part of the bilateral group but it is interesting they evolved this way.
Damn i was thinking about that when i was watching this.
not really, the base is more like an octagon stretched along the x axis.
I'm betting it's something like the starfish: octopedes are bilatrians, but their lifestyle encouraged a more radially symmetrical appearance.
@@NitroNinja324 it is literally a calcium deficient, boneless spider you mouldy lasagna fire.
@@aidanmatthewgalea7761 I'm sorry, did I hurt you somehow? That was a bit rude.
Something I've always noticed but never thought of. Thanks for the video!
It's so interesting how you get a question in your head, solve it, and share it with others
I never really acknowledged the symmetry in organisms, now it's super interesting to me
that was truly educating, loved it. Made me understand the way we look at the world on a deeper even philosophical level. I think the way how our bodies are build, with a front and back and a center of nerves (brains), must have had an influence on how we think and view the world, how we developed a philosophy of "right" and "wrong", of "forward" and "backward", of truth itself.
The idea that direction is just so advantageous that it produced the variability we have today is so fascinating. I think it also wouldve been interesting to address dominant sides, like how most of our species favors our right hand, how that might manifest in other species, etc.
In cats it is gender specific. Female cats tend to favor their right paw while males tend to prefer their left paw.
I had no idea echinoderms were bilateral! Neat.
I don't know why, but I almost cried at the thought of that fractal body plan....it's just so beautiful man xD
your content is really well written, and your insights on everything are always thought provoking!
The fact we exist for the tiniest blip in time is so crazy
I always figured it was just easier for nature to do half the work and copy itself, making two unique sides would take more dna encoding.
But our insides are asymmetrical.
Now I have to wonder stuff like: do jellyfish ever get their tentacles knotted up with another jellyfish's tentacles?
When i was younger i thought jellyfish mated that way
Yes, I've actually seen that at the beach.
this is probably the most interesting video you've done so far!!
I never really thought about how symmetrical every animal is. Just something I’ve not thought about that’s just how they are.
I love when a video pops up that answers questions I‘d never even come up with.
8:16 Kingler is real
He wacc
We are essentially just tubes of mouths and anuses :’)
Should be a tag line for a porno.
I believe that’s the premise of human centipede
@@ShadesOfGuitar 🤢
Cue* Vsauce's video of how many holes we have
What
Very Interesting! i didn't know starfish where technically bilaterians, i wonder if their madreporite(at least the ones that only have one) give any clues as to their real orientation.
XXXORIENTACION
The interesting thing is they start out bilateral in the larval state and turn radial as the grow up, adding extra arms. Interesting to know why would this happen. What is the advantage?
@@Fazzel It’s possible that all echinoderms evolved from a species in a genetic bottleneck, and that it had relatives that may have lacked radial symmetry.
My zoology teacher taught me that sea stars have radial symmetry 💀
Bless that little fish at 9:09 who didn’t want to get in the way of the shot. Such a gentleman.
3:57 Ancient australian seabed would be a great name for a band
Amazing video, this channel keeps blowing my mind
So, low gravity environments could sustain land animals with radial symmetry? I imagine something as alien as a flying jellyfish.
Sounds cool, but might not be feasible, since it seems way harder to have non deliberate movement on air.
Wouldn't flying jellyfish require a very dense atmosphere in order to pull off that trick? At least it seems so to me, but in order to have ah dense atmosphere, the planet itself would have to have a very strong gravitational field as well, so i think your point is somewhat moot. Sorry to be such a partypooper. 😢
Check out Alex "Abionenisis" Ries' brilliant work "The Shadow of the Sun".
@@BertGrink yes, and they'd most likely live their entire lives without touching the ground
It should be noted that radial symmetry on Earth appears to have been a prerequisite for bilateral symmetry.
Specifically radial symmetry requires one body orienting axis, but bilateral symmetry requires two body axes the second axis being perpendicular to the first resulting in a defined top and bottom for organ development.
In both bilaterians and Anthozoan cnidarians, bilateral symmetry was evolved thanks to gene duplication copying the original HOX gene cluster that made their first body axis possible. Anthozoan cnidarians bilateral symmetry is harder to observe as it's mainly expressed in their larval planula stage but they do apparently retain a degree of a preferential direction even as mature polyps not unlike Echinoderms
@@BertGrink -- Venus is somewhat smaller than the Earth yet has a vastly denser atmosphere, the pressure is about 90 times as high as at sea level on Earth. Saturn's moon Titan is not much bigger than the Moon, and yet has an atmospheric pressure 50% higher than the Earth. So a planet like a cool Venus or warm Titan could allow airborne jellyfish.
Thanks, this will really help drawing aliens. Something as simple as shifting how they are symmetrical is both sensible and something I'd never really considered.
It is videos like these make me so intrigued by what potential alien life forms could look like. Something as simple as their gravity being less powerful than ours could result in body structures we cant even fathom.
Very well made video! I learned a lot from this actually!
It's so obvious to me.... a cell, when dividing, the first thing it does is create bilateral shape...then splits ..extra
How do you explain asymmetrical organs?
@@morganirosonna2871 --- Is kind of interesting. Two lungs, two kidneys, but only one stomach, one heart. Yet we can survive with just one lung or one kidney. How much better off would we be with two hearts? Probably a lot less people would die from a heart attack. In a way the digestive track is just a long tube that is basically just folded up to fit into the body cavity so if it were stretched out in some ways it would be bilateral. The large intestine is somewhat bilateral. Also the stomach to some extent, just turned sideways.
Rangeomorphs look beautiful, it's a shame they don't have descendants.
I read a paper about them and their complex social network, it was an interesting read
they're called plants for all intents and purposes. you might also look into deep sea corals, same vibe
@@dewinmoonl I believe rangeomorphs are animals though
@@dewinmoonl definitely not plants. Corals are animals and rangeomorphs are believed to be stem animals.
I guess scientifically illiterate people will call them plants, as they might call dolphins fish, or call bats birds, still not correct.
@@pansepot1490 corals are pretty plant like, in that they filter their surrounding for nutrients and photosynthesize with internal algaes. i was just making an analogy of convergent evolution to make a point that those funky designs exhibited by earlier animals are also the same design that made plants and corals, aka convergent evolution.
I'm not scientifically illiterate haha I studied biology as undergrad so I'm well aware that corals are not plants, those earlier animals are not plants, and dolphins are not fish, and bats are not birds, you name it.
4:18 is the cutest squirrel I've ever seen
I agree Goku
If that’s the cutest you’ve ever seen let me introduce you to the grey ones that hang around my garden fence
@@Anon1370 wtf
@@Angel-Pizzaeater theres nothing wtf about it i do have squirrels
@@Anon1370 do you have cats
Wow, that last tidbit of info about sea stars and urchins. Very intriguing.
The term "fractal organism" is one of the coolest things I've heard.
I wish I was a fractal organism :(
I think our blood vessels are fractal
"perfect to propel forwards in a straight line"
video shows a crab!
Somehow, I lost all my youtube data including all the channels I was subscribed to. Moth light was one if the first I could remember and search to resubscribe to. I wonder why? 😉
You're intelligent, and that's dangerous to certain people. Thats why you're shit was erased.
Among echinoderms sea pigs are particularly interesting because they have independently evolved to be bilaterally symmetrical again.
as are sea cucumbers pretty much
@@rickkwitkoski1976
Sea cucumbers be like: I’ll just lay on my side to rest.
Millions of years later:
Sea cucumber: Uh oh.
Awesome video. Informative, concise, simple. Keep it up
"Bilateral symmetry is good for moving forwards", then shows a crab, that only can walk sideways
Fun fact: Did you know that in some species of Owls, the left and right ear holes are located at different elevations on their skull?
The more you know.
Is that to make each ear specially better at picking up vibrations from certain angles whilst using the information to create an "image" of its surroundings?
@@strrawberrytekken3698 With the face of Owls being shaped like radar dishes, yes. Most importantly having the ear holes located at different elevations allow them to pinpoint where exactly a noise is coming from on a vertical plane.
@@L0calLEGEND so damn cool
the title is something I would ask when I’m stoned
4:59 'When the left tropical fish is SUS'
Just a reminder, humans are a species of animal. Some people are shocked or in denial of this.
I know right? Like, just because we're able to do shit other animals can't or won't, doesn't mean we aren't animals ourselves
@@TyrannoKoenigsegg yeah you're right! lol. We have consciousness, and therefor know of our own mortality. This is what I think pushed people towards religion or other definitions of their existence for justification. Why do humans need a reason for existing?; Perhaps it is by random circumstance. We just happened to survive more efficiently through evolution by random mutation. Now we have big brains and don't know why, I believe in the sentiment that, "We are the universe experiencing itself".
@@basedheretic4616 I agree
I’ve thought about this question a lot but never had an answer, so thank you
NEW VIDEO LETS GOOOOO
animal facts Lets goooo
"With such ancient creatures, relationships with other animals are difficult to work out."
* laughs in Hallucinogenia *
To be fair, we do know what they are related to: velvet worms
Aot fans: DID SOMEBODY SAYS *HALLUCINOGENIA*
Last time i was this early animals were asymmetrical
0:46 A lobster may not be symmetrical. You can even see it in the image. The right claw is the crusher and the left is the cutter.
Nice job presenting this staple of Biology.
holy keyed janny
Owl ears- "Am I a joke to you"
I was just wondering how much symmetry is needed to count as truly symmetrical. It's on a spectrum for sure, so I wonder what the cutoff is.
Animals who break their bilateral symmetry be like "I caught a dab, not bad!"
Don't dab backwards, it's bad.
This documentary is just so good. A hundred times better than 4 minute-long badly researched documentary about the golden eagle with pictures from bald eagles, peregrines and even buzzards.
interesting that even a lot of plants exhibit bilateral symmetry too , generally they aren't entirely bisymmetrical but parts of them are , almost every leaf , fern frond and many flowers are also bilaterally symmetrical
Seemed interesting so I clicked
8:05 this adaptation is not entirely unique, in fact, most male hominids species have much larger wrists and forearms on their right sides rather than left; in order to compensate for their lack of sexual activity. 😂
do snails count as assymetrical? often their shells grow to one side.
Shell is not living. If you wear a shirt with a logo are you assymetrical? They are not really part of snails.
@@himlolo they're literally hatched with their shells
@@elliot_rat they leave their shells though
@@himlolo no they don't
Your voice is very calming
One of your best videos!
janny.........
Squirrel timestamp 4:18
No symmetry is called asymmetry.
Just like a non-theist is called an atheist,
A non theist is just called a non theist, an atheist is completely different than a non theist.
@@oatmeal8673 what's a non theist then?
@@howielowis458 Nontheism has generally been used to describe apathy or silence towards the subject of God and differs from atheism. Nontheism does not necessarily describe atheism or disbelief in God; it has been used as an umbrella term for summarizing various distinct and even mutually exclusive positions, such as agnosticism, ignosticism, ietsism, skepticism, pantheism, atheism, strong or positive atheism, implicit atheism, and apatheism.
From Wikipedia
@@Tarteh I'm not an atheist
Basically, a nontheist is apathetical towards a god existing. They could also include any group that isnt a theist.
An athiest is in direct opposition to a god existing
An agnostic believes one may or may not exist, and has put thought into the subject.
A deist believe a god can be discovered through the worlds knowledge
And theism is the belief a god or gods exist
During the ediacaran period there were also animals with trilateral simmetry! Great video!
I like the obscure life forms the most. So interesting how life develops.
I think it's important to note that literally most animals, including almost all of the obscure ones, are bilaterians. The charts in this video kind of made it look like there were only a few animal groups under Bilateria, but in reality, it's more like there are only a few groups outside of it, at least among extant animals. Those are: Porifera, Cnidaria, Placozoa, and Ctenophora. That's it. All other animals are bilateral. In fact, aside from Placozoa, I would argue none of these are obscure. Sponges, stinging tentacle animals, and comb jellies are the other three. And very few animals in those groups, aside from Placozoa, are microscopic. All other microscopic animals are bilateral. Tardigrades, rotifers, etc. are all bilateral. So yeah, I like what you said about evolution during this video, but I think the way you approached taxonomy was pretty misleading.
Comment section in a nutshell:
40% funny comments
30% questions that were answer in the video
20% actual questions brought up by the video
9% false corrections
1% lol evolution is fake
And those "evolution is fake" comments are here just because they are so fascinated and can't look away but feel obligated to respond "fake fake fake!"
Evolution is fake. Its been Proven that mutations dont occur like darwin suggested. For example, a dog will never grow gills like a fish, or wings like a bird Because all animal's genomic strictures have limits. In other words they dont have the "Genes" to gain these things. Anyways whatever.
And 1% comments about the comment section.
@@deridivisstar884 Yeah, Seals are the Examples
@@InquisitorBoomBoom seals are completely different creatures.
Funny when non believers try to explain why things are the way they are
It's literally our opinion to not believe in God.
This is blatant hypocrisy. Religion was literally made to explain why things are the way they are, because people didn’t know anything at the time.
4:51 That's a gorgeous donkey.
"Why are animals simetrical"
Owls: **awkward puppet monkey meme**