How Blood Evolved (Many Times)

[@eons]

Our friends over at Bizarre Beasts made a spectacular video about the clear blood of the crocodile icefish. It also happens to be hosted by a familiar face...kzbin.info/www/bejne/eqXYl4lrf79_jZY

[@kanyenorth5711]

6 hours ago wow

[@fzirybells]

woah

[@bonbin6053]

Yes

[@davidt8087]

I hated evolution, kept denying it. Watched this channel and then started to think its true. Then you get to the point right here whwre they say "we know it happened but there's no evidence, oh and somehow of course the first organism somehow "evolved" and survived it's initial selection and both genders somehow found each other, or one organism somehow could produce. Even worse go back all the way to the first organism. It comes alive. Then dies. Because it didn't reproduce and because it didn't have the genetic code to reproduce, it couldn't have survived and it died.

[@dorongrossman-naples9207]

@@davidt8087 The first organisms didn't have genders. They were single-celled and probably reproduced by fission (splitting into multiple parts), like bacteria do today.

[@NaturesTemper]

I'd love to see how hair evolved. And the difference between mammal and arthropod hair.

[@Leto85]

That would be interesting. I thought it was made of the same material as nails, claws, and I thought scales as well. It's probably evolved from that.

[@justherald1117]

@@Leto85 keratin, I believe

[@KlavierMenn]

@@Leto85 If I am not mistaken, hair appeared on the late Carboniferous/early Permian

[@Changitojuanito]

I second this request 🧐

[@BierBart12]

I read about arthropod hair before, and the way it evolved was REALLY weird. I think they started out as legs, with each species evolving them to a very specific purpose like feelers, hair or MORE LEGS Correct me if I'm wrong.

[@Twatical]

You've done nothing but inform the mosquito army of our greatest secret.

[@drinkwater247]

why don't we just drain our blood, so we dont have any blood too give

[@british-sama7007]

Your 666th like

[@TrieyeGamingRants]

i see

[@ajgeraci7699]

You mean the Logangsters?

[@nathanlevin6425]

I’m 0+ they like my blood the most

[@JonathanRootD]

What blows my mind is that for around 90% of Earth's existence we only had simple life. Larger complex life didn't arise until much more recently.

[@DanielDavies347]

Jonathan Root i would argue larger more complex life is yet to come

[@wrathayush]

@@DanielDavies347 exponential growth

[@wrathayush]

Maybe

[@rontayan]

Wait until we get nanotechnology and cybernetics online. Things are really going to get complicated.

[@louistournas120]

+Jonathan Root: Simpler lifeforms have more potential to change than complex systems. By simple, I mean unicellular life forms.

[@JoaoPedro-qp9cw]

That guy asking for the blood video since forever must be very happy

[@abyssstrider2547]

Everyone did ask, after all so many people were curious about it. Im sure you were, as well

[@maan7715]

I was thinking the same "oh my god, that guy must be so happy now, after all this time we got the blood video!" XD

[@monsoon_magic2874]

Extend a thanks to that guy as well.

[@super00su]

@@TheGroovyWalrus kzbin.info/www/bejne/i5Tal3iDmbtgl68

[@Dragrath1]

I honestly didn't know how they would really be able to cover it but they pulled it off despite the limited evidence in the fossil record

[@raychumon]

i see lots of people saying 'finally' but not enough saying 'thank you', so... thank you for making the video so many of us asked for!!

[@fransoto8343]

*insert THANK YOU gif*

[@fransoto8343]

@@pullupullupullup4687 well... I don't know... Maybe you could go and search it on Wikipedia or somewhere more reliable than a simple KZbin video.

[@zddxddyddw]

@@pullupullupullup4687 You're wrong. Blood is a tissue composed mainly by plasma, red and white blood cells, platelets and dissolved gases, nutrients and enzimes. There are no microorganisms. Cells have organelles, not "organs", and of those, the only one with a symbiotic origin is the mitochondria, the other organelles are just, generally speaking, internal extensions of the cell membrane or protein-based structures (like microtubules). Blood cells work pretty much like any other cell in your body (of course, with specializations for the roles they fulfill). There are no microorganisms interacting in your blood (unless you have an infection of some kind).

[@zddxddyddw]

@@pullupullupullup4687 Also, they said all that they could about the evolution of blood. Like Hank said in the video, less complex animals just move gasses, nutrients and metabolic waste by diffusion through their body walls and internal fluids. All we can say without a doubt about the evolution of blood is that, at some point, animals developed proteins in ther internal fluids that allowed them to transport gases and nutrients more effectively, and thus they could get more and more complex. Not much more than that. You have to undestand that studying the evolution of soft tissues is already hard enough in the fossil record, studying a liquid tissue is even harder, even with tools such as the molecular clock. They even showed in the video when the different blood proteins probably appeared.

[@AnalyticalReckoner]

How many is enough?

[@johncnorris]

Dracula: I want to drink your iron based protein structures with hemogloben designed to transport oxygen. Scientist: Yeah, okay.

[@jollyjokress3852]

HAHA.

[@cxffaye]

LOL 😂

[@neolexiousneolexian6079]

Haha, I swapped it out with cyanoglobin, PRANKED!!! (Also sheesh I feel woozy, my body's not meant to run off this copper stuff- *thud.)*

[@rainbowruler6453]

WHY

[@EmpressLizard81]

Which is why Lestat surviving on alligator swamp blood would be a completely absurd proposition. (Assuming, you know, vampires existed.)

[@iNuuutz]

PBS Eons: *releases video about blood* Mosquitoes: *Heavy breathing*

[@ImTheBatchMan]

@@LapisOverlord Mosquitoes: *Heavy oxygen absorption through skin*

[@demetraeconomou6096]

@@ImTheBatchMan you two made the joke 10x better

[@wesleymcspadden5437]

@@LapisOverlord it still is a joke tho it doesn't have to be logical

[@AwesomeYena]

*Mosquitoes swarm around my tablet* HEY!! SHOO!

[@thecursed01]

vampires

[@vinicius2uiciniv]

*The BLOOD video, YESSSSSSSS!*

[@iancarreras9893]

what are you a vampire

[@violentbenevolence]

it was a bloody good idea for them to post it

[@aamirrazak3467]

Are you related to Vinicius jr the soccer player

[@vinicius2uiciniv]

@@aamirrazak3467 Not at all, 'Vinícius' is just a common Portuguese/Brazilian name, not a surname

[@cadenrolland5250]

They were working on it, planning, researching, editing, recording, and today UPLOADING!

[@ferna2294]

Amazing. First time I hear about copper being used instead of iron. Great job, perfectly explained.

[@txikitule]

What about Vulcan like Dr Spock?

[@scottc346]

@@txikitule Dr. Spock was human....MR. Spock was Vulcan.

[@newname3718]

I have always called this system Blue = copper core, red = iron core.

[@glenhill9884]

@@scottc346 Mr. Spock was half human, half Vulcan.

[@grell5108]

All the Trekkies: _really?_ Huh, what a surprise :D

[@ericman5455]

You could say thats a bloody good subject

[@jazzcat1239]

no

[@linleybaruch8368]

No

[@ericman5455]

Yes

[@jazzcat1239]

No

[@ericman5455]

Yes

[@Shaden0040]

If life had to adapt to a snowball Earth at least twice, that would explain why copper was adopted early on to fix oxygen in their blood. As copper works better in cold temperatures. So it makes sense that life coming out of this snowball Earth used copper as they diversified into the Ediacaran period life forms.

[@MasterJedi86]

I never thought of it that way.

[@aniekanumoren6088]

Cool hypothesis

[@kotanightshade8989]

Also copper being a softer metal than iron may have eroded from the land into the oceans faster when complex life was evolving

[@bryal7811]

@@aniekanumoren6088 oof, that pun is so far under the radar it's sub-zero

[@dandanthedandan7558]

@@bryal7811 Yo, no need to call em out on that. Why don't we just _chill_ for a moment?

[@mooxim]

As a dungeon master for d&d, I need to make a solid mental note about this. Lizards and lizardfolk can have green blood, arthropods can have blue blood, worms can have purple blood (awesome) and arctic beasts can bleed a clearish, white blood. I might stick with describing arctic beasts having red blood because I'd like to avoid unnecessary semen jokes and the mental image of red blood on white snow is always very evocative.

[@akulsinator7680]

You can make it yellow or maybe orange like fire a contrast to their environments

[@TheAnimewolfchick]

@@akulsinator7680 yeah but that makes me think of injured/dead bugs

[@stoneraptor6219]

Could be a large difference in shade or saturation if you wanted to use blue blood again for the arctic creatures that don’t fall under other category

[@deancyrus1]

I understood about 5% of that. That's 5% more than i knew before. Really interesting stuff thanks.

[@EGarrett01]

These PBS channels, for one reason or another, seem to deliberately obfuscate the topics, focusing on jargon terms instead of what they actually represent.

[@souleevands5964]

@Everett01 It’s a science channel, they’re meant to communicate to other scientists who find the information useful, so it really should not be something to criticize for.

[@EGarrett01]

No, scientists communicate with other scientists through academic journals.

[@martinalberter6369]

This is a wonderful level of explanation for late high school and early BSc level EEE biology

[@souleevands5964]

Everett01 oh I’m sorry that the desk is considered a table Just stay off the platform if you think the vocabulary is too complicated for you

[@enderflashria3597]

*the question I've seen in the comments of every single video and its finally here*

[@Flarezap]

Still waiting for the grass video though

[@CargodHera]

Thank you, Hank Green for explaining even the most complex subjects in an entertaining and engaging way.

[@CargodHera]

@✪Hidden I know, poor baby. I love him and his brother so much!

[@nolanwestrich2602]

I've seen at least 3 comments asking for this episode, and I thought the idea was too. Thanks for the video!

[@gibranhenriquedesouza2843]

I hope one day I will see a completo video about fossilization process.

[@botas5254]

The idea was too what? I don't understand

[@nolanwestrich2602]

@@djimma5080 I meant to say "I thought the idea was _cool,_ too." I don't know how I missed adding the word "cool". Maybe I should my comment before I hit Ctrl-Enter.

[@kamoroso94]

@@nolanwestrich2602 you can still edit it.

[@ImmiGaru96MuraSaki]

@@nolanwestrich2602 Should what?

[@theshermanator5156]

“They all have bilateral symmetry” Flatfish: “Am I a joke to you?”

[@meghanachauhan9380]

NO YOU ARE FOOD TO ME

[@MichielGlas]

Correct me if I am wrong, but don't they start out vertical and over time flatten out? www.nationalgeographic.com/news/2016/08/flatfish-animals-science-colors-flounders/ Check out this article that mentions that.

[@DarkMoonDroid]

IKR?

[@spindash64]

They aren’t mirror images, but that’s not the point: they have a clear front and back, and a clear top and bottom. Bilateral symmetry is oddly not about where things are the same, but about how many directions are unique. A sponge is a rather formless blob that can make do with almost any shape. A Jellyfish has more order to it, but still is more or less just a ring. A Flatfish, on the other hand, has distinct parts that aren’t just “bumps”: it has a head where the eyes, brain, and mouth are located. It has a tail/aft section. It has a spine running along its body, from the head to the tail, also giving a direction.

[@HappyBeezerStudios]

The flatfish basically lays on it's side and decided that not looking at the ground all the time was a good idea.

[@samuelbarrow5502]

Gives a whole new meaning to “we all bleed red”

[@brickyy3106]

Ok skype

[@jellybeansd201]

ok skype

[@ivankurta1033]

Ok skype

[@genghiskhan6809]

Ok skype

[@jl_jc]

Ok skype

[@jj-qr4ro]

I gasped out loud multiple times when watching this! Science is so interesting thank you for providing another platform to make science more accessible

[@Proftheskidkid]

@ Science is the gathering of knowledge. He wasn't wrong in calling it science. The study of history is a science.

[@TheGuruNetOn]

@ Actually it's the science of evolution of the circulatory system.

[@evilpimp2475]

You didn't really gasp out loud at a video...

[@pickledpeckers7789]

Nerd

[@Paxton550730]

Get naenaed on dork

[@RickySTT]

2:54 Despite their adult appearance, sea stars are phylogenetically bilateral animals (Eumetazoa, Bilateria, Nephrozoa (≈Coelomata), Deuterstoma, Echinodermata, Asterozoa, Asteroidea). Their blood is degenerate compared to other bilaterians, but they do indeed have an internal body cavity and an active circulatory system, unlike sponges, jellies, and ctenophores.

[@thismianeptunis]

I'm glad somebody mentioned this! People deserve to know about the glorious weirdness of starfish - starting out as bilaterally-symmetric larvae and then flopping on their sides as adults to completely restructure their bodily symmetry

[@levihuttner3260]

thank you! I was confused when he said all the descendants of that hypothetical bloody common ancestor have bilateral symmetry, and then pointed to sea stars as an example of non-bilateral symmetry :P. They should really have made this more clear in the video.

[@TheRedKnight101]

Especially seeing as Starfish are some of our closest invertebrate relatives

[@Chris_da_fro]

Glad I came to read the comments

[@bensutcliffe1975]

Imagine if they lived on land

[@itzakhywell7668]

Excellent video, but you omitted the fact that orcs have black blood...

[@fabkingpuma554]

Orc joined the chat

[@drizzmatec]

Dis hears an Orky thread now boyz!!! WAAAAAAAGH!!!!

[@lukelim5094]

@@drizzmatec them blood Boyz need some waghh

[@matthewvanburen6415]

Or Vulcans having green blood.

[@celinak5062]

@@matthewvanburen6415 so they're lizards 8:45

[@themonsterbaby]

The evolution of venom and poison....

[@martinalberter6369]

That is very unique, as most examples evolved it individually and convergently. Almost always from some other protein they used or excreted, or sometimes sequestered from their food, and each example has a unique pathway.

[@GenderWoman666]

It should be: The evolution of Venom...

[@_Muzolf]

Many kinds of venoms double as digestive fluids, so most probably evolved from that. Poison is even easier, some species or populations being less edible to predators is already an advantage without it being outright poison, with your predators providing an evolutionary pressure, your evolution is driven in a direction where the bodies of each generation are more and more toxic, to the point where it is not just a happy coincidence that your body fluids are poisonous to someone else, you outright produce poison that no longer has any other function.

[@spindash64]

Z Zs Really, deliciousness is just a bizarre inversion that happens when someone thinks your species is SO delicious that they want to make sure there will always be enough of you around that they have something delicious. Actually, Livestock, from their perspective, accidentally pulled off a weirdly successful sacrificial lamb gambit: a lot get eaten, but those that breed have extremely high odds of getting their lineage to continue

[@Sara3346]

@@spindash64 To be fair what with milk goats, dairy cows and Egg producing chickens are a thing too. Aphid Husbandry in ants might also be worth noting.

[@Manoto17]

I’m glad there’s channels like these or else I’d be watching meme compilations and meme review all day.

[@dirk4081]

My life rn

[@bartoszlabuc2351]

Yeah same

[@t3chkn1ght]

Is it too much to ask for both?

[@JennieWrenStar]

I’m home now and going through my emails. It’s so weird for me, this video was being shown, whilst I was in the process of having a full blood transfusion to save my life, then I needed another few units a month later. Three months in hospital was long enough. When I was younger I used to give blood until my body became too medicated. To all the people that donated the blood that saved my life, Thank You. If you are young and healthy enough to donate please do so.

[@Crayoneater96]

Damm

[@DarkMoonDroid]

[@evaristegalois6282]

Favorite color: *the blood of my enemies*

[@rock3tcatU233]

Noob, real men enslave their enemies.

[@BigBoss-sm9xj]

Real men eat their enemies!

[@eruyommo]

Evariste Galois. You're starting to become the new Justin. I.e.: you're everywhere.

[@ShapeDoppelganger]

Then, much to your dismay, you realize that the blood of thy enemies and thy family are tinted just the same, and with the same rusty stink.

[@bangbangliu2146]

@@rock3tcatU233 Noob, real men get offended because yOU USed "mEn" aNd thAT iS sEXIst

[@shadowmax889]

Evolution of plants would be nice

[@ganaraminukshuk0]

There's more than one chemical you can use to photosynthesise; in other words, like hemoglobin, there are compounds that work like chlorophyll. (I forgot the name of it but it's purple/violet; that's all I know.)

[@nab.7250]

Evolution is not real

[@jcskehan]

Too broad of a topic I think... They already covered tress in the carboniferous video. A quick one on flowering plants would be cool, but it's kind of a basic subject. Maybe they could focus instead on under-water plants in particular? Or maybe algae in its many forms?

[@adlsfreund]

@@nab.7250 the internet is not real. you're a figment of my imagination.

[@Dragrath1]

@@ganaraminukshuk0 Yes there are quite a few different methods of photosynthesis. Chlorophyll is unique in that it is aerobic uses oxygen or more specifically breaks down water and CO2 releasing oxygen as a byproduct which has a higher chemical potential than other molecules do allowing more energy per molecule but other forms of photosynthesis evolved billions of years earlier. The most familiar of these is the purple microbes that utilize sulfur instead H2S-> SO4 etc. (though there are different types) but who knows how many types of photosynthesis occurred before the atmosphere was oxygenated effectively killing off most microbes.... I remember reading a paper about some type of Iron based photosynthesis which is quite different in that its basically impossible on modern Earth unless you have an extremely anaerobic environment....

[@commanderrockwell1123]

Hank Green shows up at PBS, too?! He’s everywhere!

[@gatiktrivedi7863]

IKR

[@lefleurdulmal]

They've gone and bloody done it

[@boy123838]

Hahaahahhahahahhahahhaha No.

[@shrimpbisque]

YES! I was one of the ones who commented asking for this video, and specifically the differences between the different blood proteins! I'm trying to write an advanced alien race with blue or green blood, and I wanted to know how to make it scientifically viable. Since hemocyanin is better in lower temperatures, I may have to scooch their planet back a smidge.

[@robinbowman1926]

You could also still use hemoglobin, but say that other proteins, compounds and/or minerals in the blood contribute to a different colour. In addition, arthropods here on Earth, have hemolymph and don't distinguish between a circulatory system and a lymphatic system. You could also say that these aliens use a completely different metabolic system which doesn't use oxygen, in that case the transport proteins for gas exchange could be wildly different. Just some things to think about, if you didn't already. Good luck on the world building.

[@marcogarcia7944]

Shrimp Bisque same here wanted to make aliens but there was one detail not right and that was how they transported nutrients and oxygen and how that evolved yet this video helped a lot on that

[@garyreed2206]

Have you read the "Giants" Trilogy by James Hogan. The aliens in this series had an interesting blood physiology. I won't give any other spoilers, in case you want to discover these stories for yourself.

[@limiv5272]

There's no reason why an alien species would have a protein in their cells, which utilize the same 20 amino acids as us, and that has the same fold and general structure of hemocyanin. You should probably just make up an entirely different sort of molecule, but have it use the same principles, like having a copper atom that does the actual binding to oxygen, because the basic rules of chemistry should still apply

[@jj-qr4ro]

Oooh where are you writing it? I’d love to give it a read

[@Brasswatchman]

Absolutely fascinating. Thank you!

[@Xagzan]

"Deliciously." - Dracula probably

[@vinny9868]

Blood of different colors and flavors.

[@qetyghg9448]

Mosticquo

[@LEDewey_MD]

Having only recently stumbled onto PBSeons, now I'm perusing previous episodes. This episode is very well done, especially considering the complexity of the subject. Lots of biochemistry to consider - and the remarkable feat of elucidating it!

[@betobermudez4075]

The people demanded blood, and blood they got. Thank you PBS Eons!

[@TragoudistrosMPH]

1:17 "The evolutionary response is always fluid." Some writer out there (Alexa Billow) deserves a serious pat on the back :)

[@RideWitMe1]

Do the evolution of egg laying mammals next.

[@last9up]

Ooh this one sounds really interesting.

[@craigme2583]

Answer one of lifes greatest questions...what came first...the chicken or the egg...

[@synonymous1079]

@@craigme2583 the chegg.

[@doomsdoor]

@Davvy Jannes well you could say that each generation of chicken is different from the last so that the egg does come before the chicken, also that chickens evolved from animals that laid eggs. Just a bad question

[@jayasuryangoral-maanyan3901]

Its a bit like placental mammals but they didn't get to the placenta part. Not to say it's not interesting but you made it sound like they may have gone from placental to egg-laying. Which is a no from my knowledge

[@bast713]

I see science I click. I hear Hank's voice and I immediately smile because I know it's going to be well explained.

[@misstruly5482]

I LOVE THIS SHOW-- brings me a great sense of peace, actually... getting some perspective on the relative novelty of the human species, and seeing that life itself has persisted in all imaginable climes and crises, against the odds. Even pandemics and the collapse of civilizations got nothing on the violent end to the Mesozoic era. Thank you for enriching us and comforting us with knowledge. The pursuit of knowledge, the hunger for wisdom, and the light of Truth can save us all. Stay strong

[@GgTTV828]

I love this comment!

[@soerry2]

We are born of the blood, made men by the blood, undone by the blood. Fear the old blood!

[@BigBoss-sm9xj]

Cool!

[@edwartexe]

Fear the purple blood then?

[@jeremybyington]

I feel like that is a Cards Against Humanity card with “blood” filling in the blanks.

[@Iamtherealtobi213]

Blood borne?

[@xXMrZentusXx]

You forgot "Our eyes are yet to open" but it was my first thought too ^^ Bloodborne is awesome :D

[@coineineagh]

As a biology student and shell collector, I'd love to see a summary of mollusks' evolutionary history. They're quite beautiful, and their adaptations to live on land and the extreme deep sea are fascinating.

[@andremoreiragraca]

THE STORY OF BLOOD. Doesn't get any more metal than that!

[@lardyify]

Some geese use a different blood protein altogether: hemoaurelium, using gold as the metallic pigment.

[@preacherjohn]

Haha! XD en.wikipedia.org/wiki/The_Goose_That_Laid_the_Golden_Eggs

[@ACBmonkey]

I can't find any info on this would you happen to have a link you could share?

[@genghiskhan6809]

Wat!!!

[@rainsy8567]

Golden goose egg :3

[@yoyo8077]

This is officially my favourite KZbin channel

[@Lindwyrm6429]

Hank Green. Works on PBS Eons, The Sci Show, and also the founder of Vidcon.

[@AlteryxGaming]

Don't forget he helped found Crash Course along with his brother, John Green.

[@Lindwyrm6429]

@@AlteryxGaming Lol I only knew about those three things XD

[@imortalones]

i've spent months of my life following these guys no joke and no regret. They are probably getting super rich. Also love those old Green blood zombie etc videogames from back in the day.

[@viniciusgheolan]

also bestselling author with "An Absolutely Remarkable Thing"

[@alir8391]

@@viniciusgheolanOn the New York times bestsellerist and In stores now in paperback 😉. And obviously co-founder of vlogbrothers, Journey into the microcosm, DFTBA Records and Nerdfighteria

[@solidoustopher]

I was skeptical about watching this, but seeing the dude from SciShow as the narrator/educator I was so relieved.

[@Zoe_EK]

Me as a biochemistry student getting really excited about all the PyMol protein structures... Just beautiful😭💕🎉

[@Fluor488]

This may be late but I want to major in biochem, any tips or suggestions that would help me better figure out what the biochem major is like?

[@namitaseshadri2638]

@@Fluor488 hey, sorry this reply is also very late! i’m a biomedical science major (not biochem) but i seriously considered majoring in biochem. basically you take a LOT of chemistry classes from biochem and orgo to analytical chemistry and stuff so definitely don’t go into it if you don’t love chemistry. my university also offers lots of interesting molecular bio courses about the immune system and stuff as a part of the biochem degree. you’ll also need to get a decent foundation in physics and calculus.

[@AmanExplorerBoy]

@@namitaseshadri2638 you are from India? If so then carrying your studies/work here or abroad?

[@namitaseshadri2638]

@@AmanExplorerBoy i’m of indian descent but i’m born and raised in Canada and i go to uni in canada:)

[@mariakayed5555]

So I came to youtube innocently to put some ambiance music to work, and then I find this!! well, guys, it was totally worth it!!!! thanks for your videos. Can you make one about how other different systems evolved (immunity, nervous, digestive, etc.) ??

[@thunder_2124]

I've been waiting for this for so long.

[@IYPITWL]

Acelomoths. Shows a picture of green beans.

[@lucrativelepton]

I find it so fascinating how we can learn so much about history just by studying the genetics. I would love to see an episode on how that works!

[@matthewstewart5566]

"We are born of the blood, made men by the blood, undone by the blood."

[@gluever54]

Fear the old blood

[@miguelcabreracastro6968]

Fear the old blood

[@sohamdas7314]

Fear the old blood

[@ironcupcake6149]

Ahh, i see you are hoonters of insight as well.

[@xc809]

@@ironcupcake6149 A hoonter must hoont

[@cyruse7027]

This was a great video. A big thank you to the PBS Eons team!

[@awesomelyshorticles]

Finally, that one guy can stop begging.

[@enli1421]

Eocene park should definitely be a thing.

[@thunderflare59]

"Blood can be green..." *Spock wants to know your location*

[@costrio]

He is green (blooded) with envy?

[@RiggingDoctor]

Thanks Hank for this deep dive into the least apparent type of connective tissue.

[@ellenengle2767]

I'd love to see a video about how fossils form. Specifically, how long after something dies does it become a fossil? And how does the fossilization process work? You guys are awesome!

[@MasterJedi86]

Yes! This is what I want to see.

[@miguelpadeiro762]

When an animal dies on a surface like mud and has their remains covered by sediments to protect them from erosion, their bones and other hard body parts turn into inorganic matter, becoming fossils, you pretty much just need to have your bones protected from erosion underground and you become a fossil

[@ellenengle2767]

@@jameskohl7959 An interesting read. Thanks for sharing!

[@ellenengle2767]

@@miguelpadeiro762 Yes! I knew all of that. I'd like to see them make a video about everything you said, but in more detail! 😁

[@miguelpadeiro762]

@@ellenengle2767 Then people dig it out and claim to be devil's work, that's all you need to know

[@CrocoduckRex]

I have blown away by the quality of these short documentaries.

[@stewartscannell8881]

10/10 for presentation 1/10 for providing conjecture as fact :(

[@samsatroncoso8249]

This is so flipping cool!!! Thank you Eons for making this video! I lost my mind with the hemocyanin bit, and had to pause the video to tell everyone in my family about it! Thank you again for this amazing video!

[@Masharulzz]

We need a video on ancestors of giraffes!

[@antoniodunbar1643]

Paracers

[@aminebenz1411]

Camels

[@skyem5250]

Giraffes diverged from camels ~50Mya and are thought to have evolved the pacing gait (moving both legs on the same side at once) convergently.

[@MrPerreaso]

it would be great if guys make a video on RH- BLOOD

[@sidneygrosshar269]

Andres piñeros They can’t because they, and nobody else, knows.

[@heatherb812]

sidney Grosshar You don’t know that.

[@justobey1939]

Heather B how do you know he doesn’t know that

[@meajor7]

Yessss!!! B- 🙋🏻‍♀️

[@DarkMoonDroid]

Type O Neg

[@veggieboyultimate]

PBS Eons can really give you a video on evolutionary history of... Everything blood, armored fish, cephalopods, winged insects, what's next...crustaceans? Cuz that would be awesome

[@falnica]

how did senses evolve?

[@mobilegamingfx4354]

My guess, natural selection. Need to find predators or prey, eyes. Eyes don't work? Death Need to hear predator or prey? Ears. Ears don't work? Death Need to smell predator or prey? Nose. Nose don't work? Death

[@diegobert4033]

Read up on Itzak Bentov model of consciousness and the nervous system

[@adeshpoz1167]

@@mobilegamingfx4354 Except that this would be a super oversimplification of the actual process, you're kind of right.

[@thunder_2124]

Stumbled upon this video early without notification squad.

[@vlad260]

"There's nothing informative on the internet" -everyone that doesn't watch this channel.

[@thomasrosebrough9062]

Literally no one says that

[@ieatbugs1996]

@@thomasrosebrough9062 some people do, but it still is very stupid to say that this is the only informative channel on the internet

[@balashibuyeeter2704]

some old people or retards do say that.

[@vlad260]

@@ieatbugs1996 when did I say this was the only informative channel on the internet and when did saracism become a lost art?

[@vlad260]

@@thomasrosebrough9062 you're aware hyberboly is a thing right? 103 figured it out but you still don't get it was a joke? Wow. That's impressive. I'll eat to see if you can figure out what I actually said.

[@radtech21]

I’ve got a few ideas: Asteroid collisions and how they affected life. How mass extinctions occurred and their effects on food webs and life cycles. Environmental pressures that caused the convergent evolution of flight by different groups and species. How honey, fruits, and other sweet products became such an important energy source for many organisms. My favorite: What influenced animals (Tiktaalik) to leave the protection of the water, and then some mammals (whales) to return to an aquatic environment. This is an awesome series! Thank you very much PBS Eons; Keep it up!

[@tislex]

Incredibly ironic that youtube recommended this to me after the news about Hank. Get well soon!

[@cruzalan003]

They finally did it!!

[@cammiller649]

Eons and Space-Time are the best things on KZbin. Thanks PBS.

[@Renagade5150]

Great video. Really enjoyed this one Eons. Keep up the good work!

[@dianayates9483]

Would love it if you would do a comparison of hemoglobin and chlorophyll. It's so interesting that they evolved to capture complementary parts of the visual spectrum but are so similar.

[@lucascaros5298]

Normally theses type of educational video make sense to me but this episode is just going right over my head

[@camiloiribarren1450]

This is how we became the mutants we are now. Without the comic book superpowers

[@MicroBlogganism]

2:56 Sea stars are a bad example here. They evolved from bilaterally symmetric animal and are bilateral in their larval stage

[@MikeS29]

I cannot get enough of these videos from Eons

[@baxterellard9320]

Continuing with the topic of the evolution of organs, can you do a video on the evolution of the eye and the diversity of eyes? I would love to learn about what the first eyes were like and why animals have evolved to have different kinds of eyes, such as goats with their rectangular pupils. Awesome video as always, thank you!!

[@toniatchison3678]

Me: 3am- I can watch one more Eons episode before bed. 4am- oh just one more.... 5am- wait, I haven't seen that one....

[@d.dementedengineerc99isurf26]

That was me last night! :D

[@generalralph6291]

Oh this is the BEST VIDEO EVER. I could watch this hundreds, thousands, millions of times!

[@ezramarmot3350]

Can you do a video on where skeletal structures came from, like how we went from weird squid like things to having skeletons, please please I’d be fascinated

[@Daniel-tf2ho]

Make an episode about bears evolution

[@philippl.2766]

I love how amazed he looks at 9:25. He is truly amazed about how awesome nature and evolution is.

[@TheWayabo]

How about claws in insects and diferentes adaptations like that

[@BertGrink]

@4one14 Just remember, if they show macro-images of said mouth parts, that you asked for it! hehe

[@ThePenguin369]

@@BertGrink ulgh. Reminded me of (female) horse fly mouths. Stab stab

[@BertGrink]

Dare I look it up?

[@TicoHyuuga]

@4one14 Those are chewers. There are several different types of mouth in insects, because insects are like tiny Medabots and you can build something totally rad like a dog sized dragonfly using the right conditions. Some other examples of types of mouths are sucker (butterflies, aphids), licker (house flies, bees) and sucker/pincher (mosquitoes). As a PSA in a biology channel: saying scorpions are insects is arguably the same as saying birds are mammals. Scorpions are in a different group with spiders and ticks.

[@RamGames-ph]

@@TicoHyuuga apparently crabs are insects too

[@sameyer716]

You guys should do a video on the unique fossils from the Burgess Shale. I remember seeing some of them in a zoology class back in high school and they fascinated me because they were just so crazy looking.

[@rossdiggle]

This was the best episode yet

[@obct537]

Maybe I'm odd, but I think an in-depth look into the evolution and diversification of different types of teeth would be interesting.

[@peapie5920]

Cool! I love the EONS series! Learn something new every episode!

[@123hypes]

truth sista!!

[@sophienugre4161]

That was very informative! Thank you for making this! Can you make a similar video for the evolution of thee immune system?

[@alecplotkin425]

This is great content! Can we have more discussion of biochemistry in future episodes? Learning about conserved domains in DNA and the evolution of proteins was hands down one of my favorite parts of my college bio classes

[@jamesathersmith2191]

Can we have a vid on South American canids

[@bingahamarwatasujana7618]

Thanks!

[@vippsmillennial6336]

This is probably the most requested video on this channel!

[@be_co_beep]

Thank you! This is fascinating! The entire channel is amazing, thank you!

[@jonboshears]

Have you talked to Slater lately Preppy?

[@sarahlynn4798]

this is my favorite channel & this was such a cool video! i never knew about purple or white blood!

[@TheKsalad]

Blood Vessels? You mean *FORBIDDEN TWIZZLERS*???

[@a-bird-lover]

This is very ominous in a way I can't quite describe

[@nipplecream3099]

A Bird Lover chewy :)

[@somerandomdudewithachannel325]

Better not be hard and sharp

[@samuelsmith2707]

Vessels are boats or containers, so how did a blood passage be come to known as a blood vessel? We could have named that blood rivers, and then named them bloody thames, bloody trent, bloody nile etc.

[@Damanism]

@@samuelsmith2707The Nile ain't just a River in Egypt. Also; Blood Canals. Blood Tunnels. Blunnels.

[@severalwolves]

Ok, yea right. But so, then when did Draculas evolve??

[@lewisirwin5363]

Somewhere between the 15th and 20th Centuries AD.

[@severalwolves]

ok. well. Hail Dracula!

[@agimasoschandir]

Tales of vampires themselves go back to Mesopotamia. An early Dracula like vampire was developed in 1819. Dracula evolved in 1897, and then later evolved starting modern versions in 1921

[@TheGuruNetOn]

You mean Leeches, Mosquitos Or Vampire bats?!! Or did you mean blood sucking loan sharks aka credit card companies?!!

[@Freeknickers24]

With movies duh lol

[@kevindean6600]

I went to school for science. Now I’m a mail man and a pool shark and a guitarist. And a dork. But I still love science. Its’ stepwise approach to explanations of natural phenomenon that can be tested and disproved seems as interesting as it was when I was in tenth grade biology. That’s why I’m watching this I suppose.

[@olgak.2415]

I migrated here from the "Crash Course" - have never seen Hank more serious. wow.

[@AifDaimon]

*FINALLY, THE BLOOD VIDEO!! **_THANK YOU!!_*

[@kennyupchurch]

We love you Hank we stand beside of you. You will bet this❤❤❤

[@thecreature7608]

This has probably been requested more than anything else on the channel and for as long as I can remember this channel being a thing. So glad you finally made the video😁👍 Also, on a complete sidenote: I've been wondering lately, if on say an alien planet animals there evolved eyes with a type of photoreceptor cell that did the job of both rods and cones in one, would they see colour clearly in the dark? Would their view of the world at night be just like the day, just like our night or would they perhaps see in slightly muted colours during night time(because of less light reacting with the photoreceptor cells etc.)? Would nocturnal eyes be much or any different from non-nocturnal eyes? Would their sleep cycles be dictated by night and day and the rotation of their planet? Would day and night time really exist for them in a prominent way? I haven't really been able to come up with a conclusive answer but am leaning towards the muted colours one, but I'm completely prepared to be wrong. Any thoughts?(and thanks for taking the time to read this btw) Extra sidenote: I think videos on the evolution of crocodilomorphs like kaprosuchus would be interesting or something about bat evolution.😁

[@fobusas]

Can it actually be combined? I don't know anything about this subject, but I imagine there could be mutually exclusive physical parameters that don't let a cell be both a rod and a cone?