It's a sponge, it's a plant, it's a worm and some other types of weird strange water bugs and strange fish. IT'S A CAMBRIAN EXPLOSION. "wow, that's animals & stuff"
I've been waiting for this. Everywhere else I looked for information like this was so boring in their presentation that I couldn't stay awake. Your information is great, explanations simple but exact, and your visualizations bring it all together in a way that is easy to digest. I love this series.
@@osmosis__ Yes it is! It actually took me a while to figure out that they weren't the same channel with different narrators because of the order my auto-play put them in lol
@LooseLipLures - Thank you so much for your kind words! Comments like these are highly appreciated and are what keep me going making this content with the amount of effort that I'm compelled put into it. I have a very hard time rushing things through, which takes its toll, but I want to feel proud of the end-product and I want it to "work" for anyone watching. So once again: Thank you! ❤️
@@shinyshoes4312 I was just searching different wording of speculative evolution, and ran into many videos that were very dry classroom types about evolution as we know it. I wish I'd noted what pages to avoid but I just kept clicking.
There's something I wonder : could radially symmetrical animals replace bilaterians ? You could imagine for example a three sided worm filling the role of the early active heterotrophs. I'm pondering if it'd be different to billaterian but my conclusion is as far as now yes since a three sided worm would have no defined up or down and could screw across the micro-biotic glue. People with better background in biology, am I correct in assuming that kind of stuff or is there something I'm overlooking ?
In principle, yes they could, but they'd have to go through a bilateral phase first. As I've tried to explain in video #2, bilateral symmetry and an active lifestyle pushes for the kind of specialization that leads to more advanced body organization and especially a centralized brain. Echinoderms are an example of such creatures with secondary, radial symmetry. In fact, many bilaterians show some degree of secondary radial symmetry which I will go into more detail with in the future. If you want an example of a highly evolved speculative alien being that is triradially symmetrical, I suggest you check out the "Amphorans" designed by Povorot: www.deviantart.com/povorot/art/Amphoran-Anatomy-180197287
@@Phrenotopia What you're telling me and in another comment section seems weird to me because cnidarians also have radial symmetry but doesn't seem to be descended from bilaterians. One thing that's true though is that pentamerism (5 planes radial symmetry) found in echinoderms is the only current odd symmetry among animals however and have indeed evolved from bilateralism. But examples of trimerism (3 planes) evolved among plants and ediacaran animals trilobozoa had evolved trimerism without any known prior bilateral stages. I could indeed envision that from a trilobozoa-like creatures - anchored on the sea floor, it'd be easier for it to move side way and thus be pushed towards developing bilateral symmetry secondarily by being stretched in one direction of its triangle shape, however one could maybe develop the ability to dig down or upward and so be pushed towards elongating vertically.
@@tonio103683 - But that is exactly my point, because cnidarians haven't evolved into particular complex forms, let alone more brainy ones. The so-called hypothetical "trilobozoan" group that fossils like Tribrachidium are referred to may actually have been one of these proto-animalian Ediacaran creatures and thus not have been particular active or even have had a nervous system.
@@Phrenotopia Ok sorry, i misunderstood your point. I thought you were saying that bilateralism was a necessary step for true radial symmetry. I think i got it now. Just curious, in what way the trilobozoans are hypothetical ?
I think it's highly unlikely, and science may one day (or possibly already has) prove it impossible. But if the conditions were perfect for a long enough time, it might be possible, assuming life doesn't inherently need water in its first developments
i don't think so. the way I think of it, if you try to combine two chemicals in their dry, solid states they probably wont react any time soon, they'd just like... sit in top of eachother. but combine those same chemicals when they're aqueous or liquid and you have a much greater chance for some kind of reaction. life is rare and cells are wet, gotta get it all mixing somehow for any sort of chance
@@joshuascott7641 Depends. The biochemistry we are based off is probably impossible to evolve on land, but theoretically speaking, there may be one we have yet to so much as consider that could. Then again, we have a pretty good idea of what substances make a good basis for life, so we probably considered all the likely ones.
In an extremely humid environment, this could happen. As in an area with constant fog or next to a large waterfall. Those environments are probably not stable long enough. Life in water is so much more likely that it has time to develop and dominate before life on land has time to start. But life without water (or other liquid) is not probable.
Well yeah probably not.. but say it's a small pool just stable and big enough for simple life to form. But an increase in size and complexity would force the cross to land.
This Series has been very interesting. Brought a lot of thoughts and reflections on how to approach development and evolution in my project. Thanks a lot !
Another thing worth mentioning regarding non-bilaterians is that a lot of the more interesting ones are either bilateral or alternating symmetrical patterns left and right. Something like a siphonophore can be technically assymetrical but only in the sense that it sometimes alternates zooid segments left and right.
That is a very good question indeed that I didn't really address. We don't actually know for sure, but I think they perhaps moved very slowly using cilia (not muscles).
@Bitten Hare - Oh, hey! I just dug up a very recent (2019) paper that shows evidence that these Ediacarans did in fact move along the substrate, albeit slowly!
I feel like a Cambrian Explosion is inevitable on planets where life exists. As life gets larger and more complex, more niches become available, and thus, more complex life becomes possible, which is a positive feedback loop that continues until an Cambrian Explosion-like event permanently sets the rate of evolution to "full steam ahead."
I ran a basic evolution simulator, this takes a petri dish and randomly mutates things in it, if you make a daylight cycle and make food rarer, the species will either start to move, or hunt each other.
One thing I do think about siphonophore-oids as a potential alternative to bilaterals is that the lack of an interconnected nervous system is probably doing them no favors. Even if we can very well imagine the central spine behaving much like a Notochord, the individualistic nature of the zooid nervous systems does not act like a limb. They may have a common circulatory/digestive system but it is hard to see how efficient limb control could be achieved by a central brain without a fully connected nervous system. Any alien analogues of siphonophores would probably need a better way to achieve command and control of their entire bodies, with some form of high-bandwidth communication between the limbs and the central part.
That's not alternate evolution, because it looks like that's basically what happened, which you will see when you watch part #7. 🙂 And then Echinoderms developed radial symmetry atop the bilateral symmetry and sea cucumbers bilateral symmetry on top of that again. 😄
I’ve only just discovered your channel and I love what I’ve seen so far. I’m very interested to see what you might have to say about radial symmetry in regards to microbiology. Annelids and cephalopods look rooted in radial symmetry and it could be fascinating to discuss this. Are there conditions in which radially symmetrical life forms would dominate the biosphere? Aren’t plants entirely radial? Perhaps these are topics you’ve already covered, so I’ll subscribe and find out. Thanks!
Thanks to the creature that decided to dig deeper instead of going to eat and relax on the surface bacteria mat. We, bilaterian, win in the end. There is no place for laziness.
Hmm a video over a month ago and this is the first I get a notification? Gad damn it TH-cam >_< An interesting take on the development of multicellular life personally I find it quite a bit optimistic as motile burrowing lifeforms developed among the Francevillian biota though they seem to have had a strange morphology not unlike the motile stage of cellular slime molds scaled up the fossils do contain traces suggesting they could not only move but likely burrow. If true it suggests this process upward in complexity can get interrupted. That said the idea that microbial mats may have suppressed complexity is really interesting and not something I had thought of. Though imagine what if they had been able to transform the world into an active biosphere 2 billion years ago? That could have changed everything... giving complex life a 1.5 Ga head start. Though looking not to far ahead of the Francevillian biota's time there is a potential reason they may have disappeared. After all it has come to my attention that the Vredefort crater appears to date to 2.023 Ga ± 4 Ma and given that thus far the Verdefort impact was the largest definitive impact event in the geological record, at least since the Paleoprotozoic glaciations, and one of only 3 preserved impact events of a remotely similar scale the other two being the Sudbury Basin 1.84953 Ga ± 0.21 Ma and the Chicxulub crater 66.043 ± 0.043 Ma. Given that the most recent of these three cataclysmic impacts has been fairly conclusively implicated as the cause of the KPG extinction which ended the dynasty of the dinosaurs the most successful vertebrate group to ever live by effectively killing off every life form on Earth that relied on primary producers, likely leaving only small freshwater or benthic marine detrital organisms and small ground nesting land animals behind, it seems quite believable that the Verdefort impact could very well have doomed the Francevillian biota. Perhaps you are right and once multicellular life evolves it can gradually overtake and end the microbial era. But regardless after the Verdefort impact it would take about 1.5 Ga for multicellular life to reappear and that occurred only after the Cryogenian glaciations which leads me to still strongly suspect that glaciations may be a prerequisite for multicellular life to evolve Another factor that may have played a role in preventing multicellular life from arising sooner on Earth is that isotopic analysis of over 3 billion year old oceanic rocks from Australia found that their was an excess of oxygen 18 which preferentially binds to exposed continental rocks (I think as CO2) suggesting that at the time there were no rocks in contact with the air in other words before 3 Ga Earth was likely a true water world with no continents. If true this ties in with earlier work studying rocks from Greenland that find the oldest continental crust shows evidence of forming under extreme heat and pressure with shock deformation in addition to the normal differential melting. The rocks in question would have been over 25 kilometers below the surface after the crater in question was formed and have been heavily eroded in the long time since. Though given the size of the area containing these rocks the impactor must have been enormous though definitely far less insane than a planetary scale impactor. It is an interesting prospect which potentially suggests that Earth's continents may have taken special circumstances to form though of course the evidence is fairly weak like anything that old. It is hard to have a conclusive sample size when there are only a few places with rocks that old on the planet....
I'm glad you like the video, no matter how late the notification! I also appreciate the insightful input. As my head has been buried in career/family/life the past decade or so, I'm woefully behind, but catching up quickly. I hadn't yet heard of the Francevillian fauna, but it does sound fascinating. You're right on the money that a substrate revolution could have happened way earlier if it wasn't for major environmental upsets. One gets a sense of the "burning of the Alexandrian library". Who knows how far things may have gotten? On the other hands, if these early glaciations were a direct result of the binding of CO2 by increasing biological activity, or in other words the initial big swings of an eventually more stable carbon cycle, then this alludes to a more predictable scenario also happening on other comparable worlds. That does not apply to extraterrestrial impacts or swinging solar activity, though, examples of which you mention, introducing more randomness. With regards to continent formation: It does indeed appear that continental shelves form over the course of billions of years after which their relative mass remains constant to some degree. Prof. Minik Rosing and other actually proposed some interesting theories that continents are formed as the indirect result of biological activity, binding minerals in different forms and creating less malleable granites overlaying the primitive igneous rocks. If that is the case, finding granite-like rocks on other planets like Mars, may indicate early oceanic life forms. All subjects I hope to touch on eventually.
With lower temperatures, and lower sunlight through the snowball earth ice shell, perhaps lower metabolism and longer life cycle meant fewer generations manifesting change and less UV to cause mutations - lower rate of change per generation and fewer generations.
I think radial symmetry is being very under appreciated here. With the same technically incorrect logic human scientists use, if it happens more than once on earth it happens everywhere well then literally every planet in the universe must have a starfish as the basic shape of a starfish has occurred many many times. Since significant variation between earth fauna and alien fauna is to be expected, we can expect that across the entire universe starfish have evolved into every ecological role at least once. Meaning there is a planet where starfish serve as horses, a planet where they are people, a planet with scary godzilla starfish, and a planet with microscopic starfish. And since startrek apparently is the most accurate prediction of the future next to the simpsons there's a race of humanoids with starfish on their heads.
@LexiByDay - Scientists say that, because they understand the ancestry of Starfish and other Echinoderms like Sea Urchins and Crinoids, as well as their developmental biology. They're part of the Cambrian Explosion (as I clearly illustrate in my videos) and their radial symmetry is secondary. Their larvae start out as bilaterally symmetrical swimmers, but then the radially symmetrical adult body start developing from the left side of the body twisting around the mouth region. There's nothing like Echinoderms in the animal kingdom here on earth; Their body plan is unique. Simply put: The Echinoderms are complex animals, because of their bilaterian ancestry. An active lifestyle involving the search for food (and more) tends to push for specialization of a head region and thus a centralized brain, as I explain in video #2 of this series. Therefore, bilateral symmetry has a universal benefit of leading to more advanced body organizations. A passive, sessile lifestyle less so, as illustrated by sponges and coelenterates like jellyfish and polyps.
Evolution reminds me of Technology. An Egyptian named Heron of Alexandria invented the first steam engine or the “aeolipile”. It didn’t became significant because either it didn’t do anything other than spin or because owning people & beating them was a more efficient means of production in the Roman Empire. Then 17 centuries later Thomas Newcomen caused the Cambrian Steam Explosion & James Watt improved on its design creating the industrial revolution. Eventually owning people became inefficient & had a rapid decline over the past couple of centuries. Let’s hope it goes extinct & becomes replaced with robot slaves.
Hopefully we could do so with fewer sins along the way. If AI ever develops sentience, and desires to exert its own will, we might have a lot to answer for.
I don't think Cambrian explosions are universal, but I'm not sure they're circumventable either. By which I mean if you want motile organisms bigger than millimeters in size you might need a Cambrian explosion. I guess one "circumvention" might be to keep creatures simple but then build complex motile creatures out of many individual zooids forming a colonial beast. That being said, this development probably requires a Cambrian explosion as the more interesting Cnidarians probably came about well into our own Cambrian, and most of the simpler early Cniderians do not have many individual zooids. Frankly I'm not sure this is really a true circumvention as it still creates a sudden diversification event, just makes a very different basis for the new creatures.
It's a sponge, it's a plant, it's a worm and some other types of weird strange water bugs and strange fish. IT'S A CAMBRIAN EXPLOSION. "wow, that's animals & stuff"
But the Sun is still a *DEADLY LASER* :-(
@@timotejmares Not anymore, there's a blanket
@@vladprus4019 Ok, but there is no food on the land, so I don't care...
I've been waiting for this. Everywhere else I looked for information like this was so boring in their presentation that I couldn't stay awake. Your information is great, explanations simple but exact, and your visualizations bring it all together in a way that is easy to digest. I love this series.
LooseLipLures check out the one by Bilbaridian it’s quite a treat to watch
@@osmosis__ Yes it is! It actually took me a while to figure out that they weren't the same channel with different narrators because of the order my auto-play put them in lol
LooseLipLures Who else did you watch that was boring? (For references)
@LooseLipLures - Thank you so much for your kind words! Comments like these are highly appreciated and are what keep me going making this content with the amount of effort that I'm compelled put into it. I have a very hard time rushing things through, which takes its toll, but I want to feel proud of the end-product and I want it to "work" for anyone watching. So once again: Thank you! ❤️
@@shinyshoes4312 I was just searching different wording of speculative evolution, and ran into many videos that were very dry classroom types about evolution as we know it. I wish I'd noted what pages to avoid but I just kept clicking.
That was a phenomenal presentation. It should be used in a variety of university classes.
CHOO CHOO HYPE TRAIN HAS REACHED THE STATION!
There's something I wonder : could radially symmetrical animals replace bilaterians ? You could imagine for example a three sided worm filling the role of the early active heterotrophs. I'm pondering if it'd be different to billaterian but my conclusion is as far as now yes since a three sided worm would have no defined up or down and could screw across the micro-biotic glue.
People with better background in biology, am I correct in assuming that kind of stuff or is there something I'm overlooking ?
In principle, yes they could, but they'd have to go through a bilateral phase first. As I've tried to explain in video #2, bilateral symmetry and an active lifestyle pushes for the kind of specialization that leads to more advanced body organization and especially a centralized brain. Echinoderms are an example of such creatures with secondary, radial symmetry. In fact, many bilaterians show some degree of secondary radial symmetry which I will go into more detail with in the future.
If you want an example of a highly evolved speculative alien being that is triradially symmetrical, I suggest you check out the "Amphorans" designed by Povorot: www.deviantart.com/povorot/art/Amphoran-Anatomy-180197287
@@Phrenotopia What you're telling me and in another comment section seems weird to me because cnidarians also have radial symmetry but doesn't seem to be descended from bilaterians.
One thing that's true though is that pentamerism (5 planes radial symmetry) found in echinoderms is the only current odd symmetry among animals however and have indeed evolved from bilateralism. But examples of trimerism (3 planes) evolved among plants and ediacaran animals trilobozoa had evolved trimerism without any known prior bilateral stages.
I could indeed envision that from a trilobozoa-like creatures - anchored on the sea floor, it'd be easier for it to move side way and thus be pushed towards developing bilateral symmetry secondarily by being stretched in one direction of its triangle shape, however one could maybe develop the ability to dig down or upward and so be pushed towards elongating vertically.
@@tonio103683 - But that is exactly my point, because cnidarians haven't evolved into particular complex forms, let alone more brainy ones. The so-called hypothetical "trilobozoan" group that fossils like Tribrachidium are referred to may actually have been one of these proto-animalian Ediacaran creatures and thus not have been particular active or even have had a nervous system.
@@Phrenotopia Ok sorry, i misunderstood your point. I thought you were saying that bilateralism was a necessary step for true radial symmetry. I think i got it now.
Just curious, in what way the trilobozoans are hypothetical ?
Their classification as a kind of cnidarians is hypothetical. My money is on them being related to other Ediacaran bionts like Charnia.
Could life have evolved on land somehow? I honestly dont see how it would, but it is an interesting question.
I think it's highly unlikely, and science may one day (or possibly already has) prove it impossible. But if the conditions were perfect for a long enough time, it might be possible, assuming life doesn't inherently need water in its first developments
i don't think so. the way I think of it, if you try to combine two chemicals in their dry, solid states they probably wont react any time soon, they'd just like... sit in top of eachother. but combine those same chemicals when they're aqueous or liquid and you have a much greater chance for some kind of reaction.
life is rare and cells are wet, gotta get it all mixing somehow for any sort of chance
@@joshuascott7641 Depends. The biochemistry we are based off is probably impossible to evolve on land, but theoretically speaking, there may be one we have yet to so much as consider that could. Then again, we have a pretty good idea of what substances make a good basis for life, so we probably considered all the likely ones.
In an extremely humid environment, this could happen. As in an area with constant fog or next to a large waterfall. Those environments are probably not stable long enough. Life in water is so much more likely that it has time to develop and dominate before life on land has time to start.
But life without water (or other liquid) is not probable.
Well yeah probably not.. but say it's a small pool just stable and big enough for simple life to form. But an increase in size and complexity would force the cross to land.
This seems accurate for very Earthlike worlds. But what if life develops on something *very* unearthlike?
I almost think that evolutionary explosions always will happen at some point, but at what point is random
Your channel is going to be very very big sometime soon. You have amazing content
This Series has been very interesting.
Brought a lot of thoughts and reflections on how to approach development and evolution in my project. Thanks a lot !
Me, too. As a biologist, it has helped me increase my understanding a lot.
You gonna do any speculative biochem?
The gathering and presentation of info in this video are fantastic. The accessory sheet is excellent. Serious work. Super thumbs up!
Thanks so much! Glad you liked it!
Another thing worth mentioning regarding non-bilaterians is that a lot of the more interesting ones are either bilateral or alternating symmetrical patterns left and right. Something like a siphonophore can be technically assymetrical but only in the sense that it sometimes alternates zooid segments left and right.
Hey, just saw good old Kimberella at 4:28!!!
It's always good to see her. :)
I may have missed this bit but did these Avalonians stay still or just float around and couldn't move "forward"?
That is a very good question indeed that I didn't really address. We don't actually know for sure, but I think they perhaps moved very slowly using cilia (not muscles).
@@Phrenotopia ah that would make sense, thanks for the reply. Keep up the great work :))
@Bitten Hare - Oh, hey! I just dug up a very recent (2019) paper that shows evidence that these Ediacarans did in fact move along the substrate, albeit slowly!
@@Phrenotopia nice. It's amazing how unfamiliar extinct life on this very planet can be to us!
I feel like a Cambrian Explosion is inevitable on planets where life exists. As life gets larger and more complex, more niches become available, and thus, more complex life becomes possible, which is a positive feedback loop that continues until an Cambrian Explosion-like event permanently sets the rate of evolution to "full steam ahead."
I ran a basic evolution simulator, this takes a petri dish and randomly mutates things in it, if you make a daylight cycle and make food rarer, the species will either start to move, or hunt each other.
Makes sense. Seems like both at the same time would be common as well. Your simulator sounds fascinating!
One thing I do think about siphonophore-oids as a potential alternative to bilaterals is that the lack of an interconnected nervous system is probably doing them no favors. Even if we can very well imagine the central spine behaving much like a Notochord, the individualistic nature of the zooid nervous systems does not act like a limb. They may have a common circulatory/digestive system but it is hard to see how efficient limb control could be achieved by a central brain without a fully connected nervous system. Any alien analogues of siphonophores would probably need a better way to achieve command and control of their entire bodies, with some form of high-bandwidth communication between the limbs and the central part.
Thanks for the credits for the subtitles. Happy to be helpful!
Thank YOU!
Thrive release inbound:
Microbial - Microbe
Avalonian - Multicellular
Cambrian - Aware
I imagine an alternate evolution that started with radial symmetry & then developed bilateral symmetry atop that.
That's not alternate evolution, because it looks like that's basically what happened, which you will see when you watch part #7. 🙂
And then Echinoderms developed radial symmetry atop the bilateral symmetry and sea cucumbers bilateral symmetry on top of that again. 😄
Damnit my internet went down but now its backk!
I wonder if Intelligent life could evolve on water worlds. Planets with no dry surface.
I can recommend my video on Proxima b: th-cam.com/video/lbifmQWbusc/w-d-xo.html
no fire no civilization
This is crazy cool but why you pushed the bell like that? You made it fall! >:(
I had it tucked nicely away in the corner of the blackboard, but then it got in the way of my waving goodbye. 😄
@@Phrenotopia XP omg! How dare you! Be more careful!
I’ve only just discovered your channel and I love what I’ve seen so far. I’m very interested to see what you might have to say about radial symmetry in regards to microbiology. Annelids and cephalopods look rooted in radial symmetry and it could be fascinating to discuss this. Are there conditions in which radially symmetrical life forms would dominate the biosphere? Aren’t plants entirely radial? Perhaps these are topics you’ve already covered, so I’ll subscribe and find out. Thanks!
I wonder how a slower but deeper tidal cycle would have effected evolution on earth?
10:18 same tune as from the intro to Antvenom's 2b2t video
Thanks to the creature that decided to dig deeper instead of going to eat and relax on the surface bacteria mat.
We, bilaterian, win in the end. There is no place for laziness.
4:00 so there's just an extinct creature called Dickinsonia? Dick in sonia? bruh
Lol I literally came in the comment section for this. Imagine how drunk the person was who named this lol.
There might be an entire branch of life made up of Dick and Sonia’s descendants
Your cartoon Ediacrabiota are charming AF
Hmm a video over a month ago and this is the first I get a notification? Gad damn it TH-cam >_<
An interesting take on the development of multicellular life personally I find it quite a bit optimistic as motile burrowing lifeforms developed among the Francevillian biota though they seem to have had a strange morphology not unlike the motile stage of cellular slime molds scaled up the fossils do contain traces suggesting they could not only move but likely burrow. If true it suggests this process upward in complexity can get interrupted. That said the idea that microbial mats may have suppressed complexity is really interesting and not something I had thought of.
Though imagine what if they had been able to transform the world into an active biosphere 2 billion years ago? That could have changed everything... giving complex life a 1.5 Ga head start. Though looking not to far ahead of the Francevillian biota's time there is a potential reason they may have disappeared. After all it has come to my attention that the Vredefort crater appears to date to 2.023 Ga ± 4 Ma and given that thus far the Verdefort impact was the largest definitive impact event in the geological record, at least since the Paleoprotozoic glaciations, and one of only 3 preserved impact events of a remotely similar scale the other two being the Sudbury Basin 1.84953 Ga ± 0.21 Ma and the Chicxulub crater 66.043 ± 0.043 Ma. Given that the most recent of these three cataclysmic impacts has been fairly conclusively implicated as the cause of the KPG extinction which ended the dynasty of the dinosaurs the most successful vertebrate group to ever live by effectively killing off every life form on Earth that relied on primary producers, likely leaving only small freshwater or benthic marine detrital organisms and small ground nesting land animals behind, it seems quite believable that the Verdefort impact could very well have doomed the Francevillian biota. Perhaps you are right and once multicellular life evolves it can gradually overtake and end the microbial era. But regardless after the Verdefort impact it would take about 1.5 Ga for multicellular life to reappear and that occurred only after the Cryogenian glaciations which leads me to still strongly suspect that glaciations may be a prerequisite for multicellular life to evolve
Another factor that may have played a role in preventing multicellular life from arising sooner on Earth is that isotopic analysis of over 3 billion year old oceanic rocks from Australia found that their was an excess of oxygen 18 which preferentially binds to exposed continental rocks (I think as CO2) suggesting that at the time there were no rocks in contact with the air in other words before 3 Ga Earth was likely a true water world with no continents. If true this ties in with earlier work studying rocks from Greenland that find the oldest continental crust shows evidence of forming under extreme heat and pressure with shock deformation in addition to the normal differential melting. The rocks in question would have been over 25 kilometers below the surface after the crater in question was formed and have been heavily eroded in the long time since. Though given the size of the area containing these rocks the impactor must have been enormous though definitely far less insane than a planetary scale impactor. It is an interesting prospect which potentially suggests that Earth's continents may have taken special circumstances to form though of course the evidence is fairly weak like anything that old. It is hard to have a conclusive sample size when there are only a few places with rocks that old on the planet....
I'm glad you like the video, no matter how late the notification! I also appreciate the insightful input. As my head has been buried in career/family/life the past decade or so, I'm woefully behind, but catching up quickly. I hadn't yet heard of the Francevillian fauna, but it does sound fascinating. You're right on the money that a substrate revolution could have happened way earlier if it wasn't for major environmental upsets. One gets a sense of the "burning of the Alexandrian library". Who knows how far things may have gotten? On the other hands, if these early glaciations were a direct result of the binding of CO2 by increasing biological activity, or in other words the initial big swings of an eventually more stable carbon cycle, then this alludes to a more predictable scenario also happening on other comparable worlds. That does not apply to extraterrestrial impacts or swinging solar activity, though, examples of which you mention, introducing more randomness.
With regards to continent formation: It does indeed appear that continental shelves form over the course of billions of years after which their relative mass remains constant to some degree. Prof. Minik Rosing and other actually proposed some interesting theories that continents are formed as the indirect result of biological activity, binding minerals in different forms and creating less malleable granites overlaying the primitive igneous rocks. If that is the case, finding granite-like rocks on other planets like Mars, may indicate early oceanic life forms. All subjects I hope to touch on eventually.
i agree with previous post. I learn from you.....thank you!
With lower temperatures, and lower sunlight through the snowball earth ice shell, perhaps lower metabolism and longer life cycle meant fewer generations manifesting change and less UV to cause mutations - lower rate of change per generation and fewer generations.
The Cambrian stage would be more accurately described as the Phanerozoic stage
Great video
I think radial symmetry is being very under appreciated here. With the same technically incorrect logic human scientists use, if it happens more than once on earth it happens everywhere well then literally every planet in the universe must have a starfish as the basic shape of a starfish has occurred many many times. Since significant variation between earth fauna and alien fauna is to be expected, we can expect that across the entire universe starfish have evolved into every ecological role at least once. Meaning there is a planet where starfish serve as horses, a planet where they are people, a planet with scary godzilla starfish, and a planet with microscopic starfish. And since startrek apparently is the most accurate prediction of the future next to the simpsons there's a race of humanoids with starfish on their heads.
Starfish horse... How and when can I get one?
@@cameoshadowness7757 *shrug* I've already done marsupial horse and cat horse I might as well go all the way and do everything horse
Starfish are bilaterians too.
@@DutchScape I don't know why people say that because they're radially symmetrical and will move in any direction without turning around.
@LexiByDay - Scientists say that, because they understand the ancestry of Starfish and other Echinoderms like Sea Urchins and Crinoids, as well as their developmental biology. They're part of the Cambrian Explosion (as I clearly illustrate in my videos) and their radial symmetry is secondary. Their larvae start out as bilaterally symmetrical swimmers, but then the radially symmetrical adult body start developing from the left side of the body twisting around the mouth region. There's nothing like Echinoderms in the animal kingdom here on earth; Their body plan is unique.
Simply put: The Echinoderms are complex animals, because of their bilaterian ancestry. An active lifestyle involving the search for food (and more) tends to push for specialization of a head region and thus a centralized brain, as I explain in video #2 of this series. Therefore, bilateral symmetry has a universal benefit of leading to more advanced body organizations. A passive, sessile lifestyle less so, as illustrated by sponges and coelenterates like jellyfish and polyps.
wanderful
Evolution reminds me of Technology. An Egyptian named Heron of Alexandria invented the first steam engine or the “aeolipile”. It didn’t became significant because either it didn’t do anything other than spin or because owning people & beating them was a more efficient means of production in the Roman Empire.
Then 17 centuries later Thomas Newcomen caused the Cambrian Steam Explosion & James Watt improved on its design creating the industrial revolution. Eventually owning people became inefficient & had a rapid decline over the past couple of centuries. Let’s hope it goes extinct & becomes replaced with robot slaves.
Hopefully we could do so with fewer sins along the way. If AI ever develops sentience, and desires to exert its own will, we might have a lot to answer for.
I don't think Cambrian explosions are universal, but I'm not sure they're circumventable either. By which I mean if you want motile organisms bigger than millimeters in size you might need a Cambrian explosion.
I guess one "circumvention" might be to keep creatures simple but then build complex motile creatures out of many individual zooids forming a colonial beast. That being said, this development probably requires a Cambrian explosion as the more interesting Cnidarians probably came about well into our own Cambrian, and most of the simpler early Cniderians do not have many individual zooids.
Frankly I'm not sure this is really a true circumvention as it still creates a sudden diversification event, just makes a very different basis for the new creatures.
NOT FIRST!
cool!
yoooo