When Fish Wore Armor
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- čas přidán 23. 07. 2018
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420 million years ago, some fish were more medieval. They wore armor, sometimes made of big plates, and sometimes made of interlocking scales. But that armor may actually have served a totally different purpose, one that many animals still use today.
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References:
Sim, Min Sub, Shuhei Ono, and Matthew T. Hurtgen. "Sulfur isotope evidence for low and fluctuating sulfate levels in the Late Devonian ocean and the potential link with the mass extinction event." Earth and Planetary Science Letters 419 (2015): 52-62.
Sallan, Lauren, and Andrew K. Galimberti. "Body-size reduction in vertebrates following the end-Devonian mass extinction." Science 350.6262 (2015): 812-815.
Afanassieva, O. B. "On the growth and regeneration of the exoskeleton in early jawless vertebrates (Osteostraci, Agnatha)." Doklady Biological Sciences. Vol. 466. No. 1. Pleiades Publishing, 2016.
Anderson, Philip SL, and Mark W. Westneat. "Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator." Biology Letters 3.1 (2007): 77-80. rsbl.royalsocietypublishing.or...
Arsenault, Marius, et al. "New data on the soft tissues and external morphology of the antiarch Bothriolepis canadensis (Whiteaves, 1880), from the Upper Devonian of Miguasha, Quebec." Recent Advances in the Origin and Early Radiation of Vertebrates: Verlag Dr. Friedrich Pfeil, München (2004): 439-454. www.pfeil-verlag.de/wp-content...
Brazeau, Martin D., and Matt Friedman. "The origin and early phylogenetic history of jawed vertebrates." Nature 520.7548 (2015): 490.
Brett, Carlton E., and Sally E. Walker. "Predators and predation in Paleozoic marine environments." The Paleontological Society Papers 8 (2002): 93-118. www.cambridge.org/core/journa...
Carr, ROBERT K. "Paleoecology of Dunkleosteus terrelli (Placodermi: Arthrodira)." KirtlandIa, the Cleveland Museum of Natural History 57 (2010): 36-55.
Carr, Robert, K. "Placoderm diversity and evolution." Bulletin du Muséum national d'histoire naturelle: Sciences de la terre, paléontologie, géologie, minéralogie. Section C 17 (1995): 85. www.researchgate.net/profile/...
Chevrinais, Marion, Claire Jacquet, and Richard Cloutier. "Early establishment of vertebrate trophic interactions: Food web structure in Middle to Late Devonian fish assemblages with exceptional fossilization." Bulletin of Geosciences 92.4 (2017): 491-510.
De Vleeschouwer, David, et al. "Timing and pacing of the Late Devonian mass extinction event regulated by eccentricity and obliquity." Nature communications 8.1 (2017): 2268. www.nature.com/articles/s4146...
Denison, Robert H. "The soft anatomy of Bothriolepis." Journal of Paleontology (1941): 553-561. www.jstor.org/stable/1298812
Doherty, Alison H., Cameron K. Ghalambor, and Seth W. Donahue. "Evolutionary physiology of bone: bone metabolism in changing environments." Physiology 30.1 (2015): 17-29.
Donoghue, Philip CJ, and Ivan J. Sansom. "Origin and early evolution of vertebrate skeletonization." Microscopy research and technique 59.5 (2002): 352-372.
Giles, Sam, Matt Friedman, and Martin D. Brazeau. "Osteichthyan-like cranial conditions in an Early Devonian stem gnathostome." Nature 520.7545 (2015): 82. www.nature.com/articles/natur...
We've hit CZcams's description character limit so you can find all references we used in this video here: pastebin.com/raw/XkhEwmyU - Věda a technologie
Also known as the fishieval era
Iain Hansen nice pun
DON’T
Bruno Sanchez Viera I already did
or a mediefish era
Iain Hansen lol good one
Looks like the eyeball was even made of bone. Wild
If you look at a fossil close-up you´ll see there´s a little bowl-shaped plate of armor at the front of the eye (with, of course, a hole for the pupil) but not an entire orb.
Those are called scleral rings. They protect the eye, but are not the eye itself. Some other animals have them as well, including the last surviving dinosaurs: the birds.
Even stranger when you think that bone is basically just rock and glue. These fishies are some of history's coolest pet rocks.
TerminalVerbosity i agree a swimming pet rock is indeed cool
I heard the eyelid may have been bone but not the eye itself.
Wow! An animal trait not used for attracting mates for once!
well we dont know that...
Eric Weng Maybe?
Eric Weng reproduction is literally the only goal of life
You're onto something there - it might very well have been the case.
To distinguish themselves from other similarly looking species.
Anyway this must have cost quite some energy to develop in each individual and they died out when the super energy rich era ended.
"Oh your plates are so big and strong! Wanna head to a movie?"
Can you guys talk about the period immediately after dinosaurs before the rise of mammals and before many niches were refilled?
What do you want to know?
EVERYTHING
Jacobbgross just what the time period was like. How creatures took niches. How desolate the world was. I just feel no ones ever talked about it. Dinosaurs died then boom mammals.
I would love an epsiode that talks about it. Tbh the only species I know from that time period is Titanoboa, and even that is streching out a couple million years.
Mass extinctions takes time. Non-Avian Dinosaurs were phased out by mammals over the course of hundreds of thousands of years. There wasn't one and then the other with a desolate world in-between; they lived together and one grew in numbers while the other receded.
Could you cover the evolution of blood?
Up!
YESSSS
This one's been suggested a lot lately, and it's an interesting topic. I'm all for it.
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I would love that
Sacabambaspis. Sound like an alternative abracadabra.
Sacabambaspis sounds like an exotic summer song.
For my next trick, I will make the armoured fish disappear! Sacabambaspis, dunkleosteus, ALAKAZAM!
Derek Floyd what about ptericthyodes and bothriolepis???
Even the non-scientific names can be confusing. For instance, the bear dogs and the dog bears are two different groups of mammalian carnivores, that aren't super closely related. Their official names are the Amphicyonidae (bear dogs) and the Hemicyoninae (dog bears).
Vanger48912 I immediately thought of Harry Potter's spell as soon as I heard it😂
Much love to our Eons amigos! Thanks for the shout-out 🌎🔥
Hot Mess I don't know you are CZcamsr
Yeah, I checked out _Hot Mess_ -- I've been kind of disappointed -- seems rather sophomoric.
I just love how Hank talks about any and all topics. I makes me want to watch all of his explanations over and over again. He makes learning fun.
We are the fish of the devonian period
We wear armor when we're able
We do routines and chorus scenes
With armor impeccable
No this is Patrick,
Is this the Krusty Krab?
Kawsar Hussain no, he is patrick
able does not rhyme with impeccable
Foamy K it does in Monty python
I have to catch the prawns allot
Jaws: The Origin.
Jaws origins
its funny because its actually science
The ancestor of sharks is _cladoselache_ . By the way, there were prehistoric sharks back at the devonian.
I’m actually heading to Montana next week to go study Paleontology . Honestly the reason I got into Paleontology wasn’t Jurassic Park. It was actually when first saw a Placoderm fossil when I was younger. After that it just sorta took off from there.
How's it going in your studies?
I’d like to see a video on the first appearance of opposable thumbs in the fossil record and its evolution
I give this suggestion a thumbs up.
Good idea!
I think that prior to thumbs, tetrapods had, like 8 fingers or so, which was adapted from the fins of the acanthostega
In which animals?
Opposable thumbs are OP
If all the calcium dependent armored fish died, could it have been ocean acidification? Climate Change can affect the pH of the ocean.
Yes, this idea hasn't been tested but it would help explain why such highly successful armored fishes (Placoderms, osteostracans) perished while less-protected Chondrichthyes and Osteichthyes survived.
What if their deaths caused the acidification in the first place? All that bone contains calcium which is acidic.
Been a while since I saw a real question comment on CZcams.
I’m already Sans Undertale that’s what I was thinking but might be unlikely
@I’m already Sans Undertale Calcium is far from acidic. The opposite in fact.
Love you Eons!!!! I actually do outline notes and treat the videos like lectures! Thank you very much!!!
I LOVE LATIN NAMES!
They roll off the tongue. Nice job not bumbling up those words.
Why did birds lose thier teeth and form beaks instead?
I'm not entirely sure why either, but I've heard one of the reasons was to help them eat seeds since they were one of the only major food sources after the meteor.
I don't know if the weight theory is still really supported. There have been more flying animals in earth's history with teeth than without, and many birds have heavy beaks (like the toucan.)
It's also worth noting that most herbivorous dinosaurs had beaks, such as triceratops and pachycephalosaurus; this is probably because they did not have incisors; however, these dinosaurs still had teeth, which supports the weight idea.
Then again, turtles have toothless beaks, and they don't fly, either.
It's worth noting that many birds have evolved some sort of "tooth replacements", as well. Look at pictures of the mouth of a penguin or a goose, for instance.
It seems to have been a weird trend in certain dinosaur lineages, not just the bird line. Ceratopsians, duck billed dinos, etc. aren't therapods like birds, yet evolved beaks.
It's not just the dinosaurs. Turtles have beaks, and so do some fish. Again, I'm pretty sure it's because these animals don't have incisors to rip plant matter apart before chewing it, so they use a beak for that purpose instead.
Oh, hey. I found something relevant.
dml.cmnh.org/2014Mar/msg00086.html
I just realized, Placoderms and Turtles are kind of convergent. Both have an exoskeleton and both use a sharpened bony plate to bite instead of teeth. Dunkleosteus especially reminds me of a snapping turtle.
How far back in time could a stranded time traveler still survive by living off the land?
depends in the atmosphere makeup too I'd assume.
Without electricity and oil? About a week.
@Yuu Asano ...touché
For anyone glancing at this out of curiosity like I was,
Even a few hundred years ago the bacteria/viruses/whatever would have been so, so different chances are you would get sick and die, especially considering a few years ago health care was so much worse
Absolute admiration for this channel! #PBSEONSISLOVE
I THOUGHT YOU WERE EXTINCT
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On Sis Love? You are sick!
Can you do a video on the evolution of skin?
We take our skin for granted but nearly everything else is covered in some other way. A life forms covering is a very important thing.
You gotta just hold your organs in place
All vertebrates afaik have skin they just also have some other organic covering on top of that (scales, hair, feathers, etc), there’s always skin under that
I want an episode on the evolution of the first mammals. It’s a commonly overlooked topic.
Fungal Boi I've been wanting for them to discuss why bats are the only flying mammals exist. Been commenting this in almost every videos. Still they haven't noticed😂
They look like they still would be super competitve in todays oceans. It would be really interesting to know, why exactly they died out.
The way I heard it predators like Dunkleosteus made armor obsolete because no amount of armor could save you from that bite, so speed became the new strategy.
That makes sense. Thanks!
Dunckleosteus itself is a Placoderm that wore the armor! After the Devonian mass extinction, nature rolled the dice and armor didn't come up again! :)
A shark would shred it
Fun fact: armor fish still exist today. Look up armor catfish from the amazon.
I was wanting an episode on placoderms. They are so interesting, just like prehistoric crocodilomorphs.
Though I haven't watched it all yet, I know I will love it based on previous episodes and the average quality of your content(superb btw)
Keep up the fantastic work😀👍
1:09 my new favorite word!
Could you do a video on the history of grasses and grasslands? It seems slightly mundane but i bet there is actually some really cool adaptations and effects.
One of my favourite prehistoric subjects!! The evolution of fish and their now extinct branches is fascinating!
this guy is my favorite. he should present more of these videos
"[...] lived in the costal waters of Bolivia"
lol
Hank and your crew, you're remarkable. Patreons, you're remarkable too.
Placoderms are my favourite, I love how diverse they are
Ahhh love the Dunkleosteus! The Field Museum's fossil specimen is one of my favorites.
This series is consistently captivating! Please continue!
Speaking of fish, do a video on how some fish can breathe air! Such as the lungfish, some loaches and anabatoids (through their labyrinth organ) !
They wore fish scale armor ;)
(btw this was an actual thing for those that did not know)
totally in love with this channel! Don't discontinue anytime soon PBS this is really good and has inspired me in what I may be happy doing in the future.
Seriously, with such weird creatures like Doryaspis truth seems far stranger then fiction.
Jack Kraken than
I am a very huge fan of this show~ Thank you so much PBS EONS for the great content~
Hi I'm a evolutionary biologist PhD student and I learn and enjoy a lot Eons! I wonder if Dunkleosteus could get up to 9 m. I would like to know the reference. Thank you!
2:31 "Proud Latvian noises"
Had to rewind the video to confirm that indeed Latvia was mentioned 😃☺️
I love how he reads the scripts. the inflections in his voice. It makes the video entertaining and engaging while also teaching us awesome science stuff.
Loved that, fascinating, thank you!
Thank you for doing these
A true gem of a show.
I love this series! Learning so much
Jellyfish: “... darling it’s better, down where it’s wetter - take it from me!”
You know how when you're enjoying a video so much and you've already gotten so much new information and you think "hell it must be over soon" and it only been half the video??? That's PBS Eons!
Best Sci INFO !! Lovin’ it! Thanks for doing these shows for me!! I’m flattered ..
this is truly the greatest channel on youtube!!! thank you so much for making this content!
Just found this channel today and it is amaaaaaaazing!!!!
Awww, poor things! It’s hard to imagine how their lives were from their perspective, but it probably wasn’t very nice.
i just squealed and exclaimed "Hank Green!"
I love this man. Unlike others who merely read fast to the camera, he tell the story and makes it fascinating.
amazing videos with amazing concepts
EVOLUTION OF EYE is what I wanna know
I really love this channel been interested in this ever since I was little fascinated about the past and what it was like.
Man, this is so interesting. I love this channel
Hey friends! Where's this week's video at! I can't get enough of this channel and y'all making me wait!
Love the new episode. Much kudos! How about an episode about how fishes invaded freshwater? I just love palaeontology 😂
I love how I find these videos as I’m learning about them in Anatomy lol
"Quick! You have 3 seconds to give it a name."
"Uh..um.. SaCaBaMbAsPiS"
I hear Latvia i press Like. Čau visiem.
maby it doesn't belong here, but it would be great e video explaining the process of shifting number of chromosomes through species. It's comfusing that in a population of primates all with 48 chromosomes, one individual showed up with only 46 and managed to reproduce effectively and generating a new species (humans).
That's something that always interested me as well.
Indeed, more explanation on chromosomes would be helpful and very interesting, though i'm not sure this particular channel is the place for it. It's probably something for that "It's okay to be smart" guy to tackle, or another co-op between the channels would be cool too
Here's my thoughts on that, I'm no expert, just another nerd trying to wrap his head around how the world works. It's always been my sense that environmental pressures split a population of creatures into two groups. Doesn't matter what the pressure is, mountain pops up in the middle of the territory, islands move further apart, whatever. Every time this happens there's a last time that the two groups interbreed, if you have perfect knowledge you can name the day it happened. But after that day the two groups are still the same species and will continue to be for thousands perhaps millions of years. The changes that eventually turn them into two different species accumulate over a long long time. A change in the number of chromosomes feels like a really really big change and maybe it is, or perhaps it's as simple as a chromosome breaks in the middle and now there is two chromosomes. The two chromosomes contain all the same data as the one so perhaps they remain interoperable for some time. Perhaps when a one chromosome individual breeds with the two chromosome individual the one-piece chromosome holds the whole thing in one-piece and the two-piece trait is passed on recessively.
This is quite likely all foolishness but sometimes the first step in figuring out how something works is coming up with a way it might work. Hopefully it's something to think about, that's all I'm going for.
you just watched the new video from "its ok to be smart" admit it 😂
Agreed -- that would be rather neat.
its 4am and im laying in the dark, sofly whispering "sacabambasis" over and over.. hoping my husband is actually asleep, cause i sound insane rn. its fun tho
Very good videos!!! Thank you!!!
You guys are awesome, love you all. I always thought armoured fish looked so cool, sweet as to learn how they all came about.
That said, I'm a preschool teacher in Australia and we happened upon a wild echidna in our travels. The children wanted to know about quills, so I figured who better to ask than Eons? Some dinosaurs are shown with quill like details in some art, whimsical knowledge tells us they are related to hair, but when and why did they turn hard and sometimes venomous?
They aren't related to hair. They were just hair-like.
Well there you go, and hence why I said whimsical knowledge. It isnt an area I've researched myself yet, I have very basic understanding at best thusfar. Will get there eventually.
...when were venomous quills mentioned? Anyway, those dinosaur quills were actually feathers, not hair. Hair exists on the other side of the amniote family tree (that being the side of the synapsids, of which the only living members are the mammals.)
To summarize the family tree: the amniotes, or those tetrapods with a hard shelled or internalized egg, are split into the _synapsids_ (including the aforementioned mammals),
and the _sauropsids_ (more commonly known as the reptiles.) the sauropsids include lepidosaurs (lizards, snakes, and the tuatara (and it's ancient relatives)), archosaurs (including crocodiles and dinosaurs (and, by extension, birds)), all the various groups of marine reptiles (which are not closely related), the turtles (although we still have no clue where they are on the reptile family tree), and any other reptile you can think of.
Regarding body coverings, just remember this:
synapsids have hair, dinosaurs have feathers, and pretty much everything else has scales. That's a simplified statement, but it works as a general guideline.
Globin347 They weren't mentioned, just something that the children had heard and asked me about and I had no response to. I don't want to give them information that is wrong, so I'm looking for info that is right. But if I can introduce them to Eons and other PBS studios stuff, set them on a path for learning, I reckon I'm preschoolling alright.
Well, I've never heard anything about venemous quills, so I'm not sure where you got that information. All the same, PSB Eons is certainly not a bad channel for learning.
The Silurians are also a reptilian race from Doctor Who
ChickenWire ffs
Direct descendants of the dinosaurs.
And the nowadays manatees
Good stuff, hope to see more :)
Thank you... I learn something new everyday...
Please do where hair came from
It comes from your head
I love those videos! They're amazing, and here is my suggestion: Could you make a video talking about amphibians? When they appear, the biggest of all, is it true that they were the first animals to make sounds, and more...
Petition to nickname the placoderms "terror fish"
I have a hypothesis on why placoderms died out. They obviously could not have had stiff armor on their tails, or else they would not have been able to swim. But when trying to escape from a predator, the tail is what would have been facing the predator. Therefore, their armor could only have been useful when attacking opponents who were going to fight back. Armor would actually be a detriment when trying to escape from a larger predator because it would slow you down.
Placoderms were the first group of fish who gained dominance in the ocean. They must have taken this spot from arthropods and cephalopods. Arthropods always have armor of course, and cephalopods during this period had shells. Maybe fights between large placoderm predators and their prey were time consuming because of the armor of their prey, and they needed their own armor to deal with pincers, stingers, beaks, and tentacles.
Once placoderms had cleared away the competition from the arthropods and cephalopods, their armor was no longer useful, because a fish who's been bitten on the tail puts up much less of a fight than say, a crab. So they evolved their armor to deal with large and numerous arthropods and cephalopods, and once they won, their armor was no longer needed.
Armoured fish look like Pokémon
The pokemon was a coelacanth
Within the last month I’ve learned and committed to memory the timeline and major significance of every eon, era, period and even some epochs throughout our entire geologic history. It’s 100% all thanks to your incredible program.
Understanding how we fit into the strange and enormous puzzle of our evolutionary history truly gives you pause and wonder - thanks for everything and keep it up!!
Learned a lot. Thanks guys
Another great video, keep it up! :D
This is a good channel👍🏻
Thanks for useing the metric sistem!!
That was awesome!
The editing in these videos are always really high in quality and always surprises me.
Great video and excellent use of a 'Little Mermaid' reference! Could you do an episode on how the different types of blood came to be?
Dunkleosteus AKA: Fish armor DLC
👏👏👏👏👏👏
Love you guys!
The only channel where I willingly choose not to skip any ads.
Maybe these fish died out for the same reason some startups do: they couldn't scale!
better...wetter...under the sea. OMG! I lost a mouthful of coffee and Hank owes me a new computer screen.
Bone armored Great White Sharks , NOW that's a scary thought.
Also love You PBS Eons and Scishow, too !!!
Thanks for short and sweet story
We do have one particular placoderm to hopefully bridge the gap, Entelognathus. Keep smart.
Disappointing that they omitted the recent Silurian discoveries (Entelognathus, Qilinyu) from China as it completely solves all the issues they claimed were unresolved at the conclusion of this video.
Always wondered about the mechanism for renewal of the plates that Dunkleosteus used as "teeth". Did it grow as it wore down or once it was gone, or 'that's all folks'
I learn new things all the time watching Eons. I was totally unaware that Sacabambaspis was armored. It just shows development on life on earth is more complicated than one might assume.
Hello Eons team, I am a big fan of your videos, thanks for all the awesome understandings that you share with us. I would like to know more about the direct evidence for plate tectonics, how the scientific community came to be convinced by the theory, and how certain or not we can be of the existence of super-continents like Pangaea etc.
I love every video from PBS Eons! The only crtiticsm I have is the "page turn" sound effect frequently used in your videos. It sends chills down my spine! Is it just me????
Thank God, I thought I was the only one! I don't even know why!
I actually really like the sound, weird.
I don’t even know what you’re talking about.
Danquebec01 1:22
Jade Riley
Wow, it’s barely noticeable. Personally I’m neutral about it.
Shoutout to ma boi Doncleosteus. I still miss ya bro. Say hello to Biggie from me. RIP.
this my fave pbs eons presenter
I was just looking at a video about dunkleosteus, are you watching me? xD
Question? Was the ocean as salty in the Devonian as it is now? @pbseons
jarrett p Couldn’t have been as salty. Internet commenters didn’t exist back then...
Graham Strouse oh damn
Oh my god! Feels so great to hear my country at 2:33 !
Man I love listening to this stuff
These videos are awesome, kind of intermediate paleontology level that's hard to find!