How Two Microbes Changed History

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What if I told you that, more than two billion years ago, some tiny living thing started to live inside another living thing … and never left? And now, the descendants of both of those things are in you?
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References:
Chemical and membrane similarities between prokaryotes and organelles:
Margolin W. 2005. FTSZ and the division of prokaryotic cells and organelles. Nature Reviews Molecular Cell Biology 6(11): 862-871.
doi:10.1038/nrm1745
Wise RR, Hoober JK. 2007. Structure and function of plastids. Springer, Berlin. (Chapter 5)
ISBN 9781402065705
Zeth K, Thein M. 2010. Porins in prokaryotes and eukaryotes: common themes and variations. Biochemical Journal 431(1): 13-22.
DOI: 10.1042/BJ20100371
Fischer K, Weber A, Brink S, Arbinger B, Schünemann D, Borchert S, Heldt HW, Popp B, Link TA, Eckeskorn C, Flügge U-I. 1994. Molecular cloning and functional characterization of two new members of the porin family. The Journal of Biological Chemistry 269(41): 25754-25760.
www.jbc.org/con...
Fairman JW, Noinaj N, Buchanan SK. 2011. The structural biology of β-barrel membrane proteins: a summary of recent reports. Current Opinion in Structural Biology 21(4): 523-531.
doi.org/10.101...
Mileykovskaya E, Dowhan W. 2009. Cardiolipin membrane domains in prokaryotes and eukaryotes. Biochimica et Biophysica Acta (BBA) - Biomembranes 1788(10): 2084-2091.
doi.org/10.101...
Organelle genomes, organelle dependence on the host cells:
Timmis JN, Ayliffe MA, Huang CY, Martin W. 2004. Endosymbiotic gene transfer: organelle genomes forge eukaryotic chromosomes. Nature Reviews Genetics 5: 123-135.
doi:10.1038/nrg1271
Andersson SGE, Zomorodipour A, Andersson JO, Sicheritz-Pontén T, Alsmark UCM, Podowski RM, Näslund AK, Eriksson A-S, Winkler HH, Kurland CG. 1998. The genome sequence of Rickettsia prowazekii and the origin of mitochondria. Nature 396: 133-140.
doi:10.1038/24094
Stoebe B, Kowallik KV. 1999. Gene-cluster analysis in chloroplast genomics. Trends in Genetics 15, 344-347.
dx.doi.org/10.1...
Douglas A, Raven JA. 2003. Genomes at the interface between bacteria and organelles. Philosophical Transactions B 358(1429): 5-18.
doi: 10.1098/rstb.2002.1188
Dagan T, Roettger M, Stucken K, Landan G, Koch R, Major P, Gould SB, Goremykin VV, Rippka R, Tandeue de Marsac N, Gugger M, Lockhart PJ, Allen JF, Brune I, Maus I, Pühler A, Martin WF. 2013. Genomes of stigonematalean cyanobacteria (Subsection V) and the evolution of oxygenic photosynthesis from prokaryotes to plastids. Genome Biology and Evolution 5(1): 31-44.
doi.org/10.109...
History of the idea:
Sagan, L. 1967. On the origin of mitosing cells. Journal of Theoretical Biology 14(3): 225-274.
doi.org/10.101...
Oldest fossil appearances:
Bengtson S, Sallstedt T,Belivanova V, Whitehouse M. 2017. Three-dimensional preservation of cellular and subcellular structures suggest 1.6 billion-year-old crown-group red algae. PLOS Biology 15(3): e2000735.
doi.org/10.137...
Bengtson S, Rasmussen B, Ivarsson M, Muhling J, Broman C, Marone F, Stampononi M, Bekker A. 2017. Fungus-like mycelial fossils in 2.4-billion-year-old vesicular basalt. Nature Ecology & Evolution 1, Article number: 0141 (2017)
doi:10.1038/s41559-017-0141

[@Qce-i6d]

I needed a video this clear on the subject back in middle school. lol

[@nishbrown]

I would have settled for the internet, at all. I find it hard to believe that any student these days, could not learn. All of the information is a million times more accessible than it was 25+ years ago.

[@NonDelusional74611]

Silly student. That’s not what school is for.

[@sMASHsound]

Most of us did, man.

[@sMASHsound]

Most of us did, man.

[@LisaBeergutHolst]

@@NonDelusional74611 Exactly. School is where we all get assigned our places in the social hierarchy. Any learning of subject matter is incidental and most often quickly forgotten.

[@jivejunior8753]

I would be very pleased if you did an episode on the evolution of insect flight. Basically every explanation I've heard so far is: "Once upon a time, some insects popped onto land and grew wings. The end." But this channel is such a high-quality gem, so I thought y'all could make it clear for all of us! Thanks!

[@ThrottleKitty]

From what I've heard, beetles first developed outer shells that would open and shut, either to make noise for mating purposes or to allow them to mate without having an exposed soft body, and a membrane between the two halves eventually developed into a wing. For other insects, I'm not really sure.

[@Dragrath1]

Beetles and their relatives the other metamorphic insects only appeared very late in the earths history during the Mesozoic era. Flight itself evolved much much earlier (by at least the Devonian according to what Iv'e read) and those fossils are quite complex and specialized indicating they may have appeared quite a bit earlier. It was only after the Great dying, the only mass extinction to severely affect insects that the metamorphic insects were able to spread and diversify into the familiar forms like beetles wasps bees and butterflies which seem to have coevolved with the flowering plants.

[@greensteve9307]

Ditto!

[@harrisonvc9175]

They did

[@kitkat2976]

Jive Junior dd

[@charlesanderton]

I just finished reading The Story of Earth: The First 4.5 Billion Years that you recommended on the livestream, thank you it was such a great book!

[@Linkous12]

Richard Dawkins' The Ancestor's Tale is really good too.

[@magnuspeacock5857]

And Unweaving the rainbow by Dawkins

[@fahimaalfarabi1646]

Was looking for a book like this. Thanks for mentioning!

[@rickcrume739]

But they left out 4.1billion that actually did not exist. And they do not have physical evidence

[@KenKopin]

The Answer was inside us, all along.

[@vampyricon7026]

42?

[@bouenyfolefack3489]

42!!!

[@ethanotoroculus1060]

FOURTY TWO

[@mathieuvanleeuwen7127]

As usual

[@AppleYou]

Sorry, it’s 42.1. Sorry to be a party pooper.

[@KarlBunker]

Wow; there's no giant stompin' dinosaurs in this episode, but the story it tells is amazing and awesome.

[@HappyBeezerStudios]

But there was a dinosaur in it.

[@mnomadvfx]

Actually there is - they're the descendants of this symbiosis just as we are.

[@VOMITQUEEN]

Tbh I think that dinosaurs are overrated sometimes, I feel like the earlier of prehistoric eons tend to be much more fascinating. At least to me! We all know about dinosaurs, but I personally want to learn about much more ancient type of creatures and how they came about instead.

[@moldytaters4190]

I've learned more from one video on this channel than I have learned in school in 12 years.

[@FelipeKana1]

Kason Zechiel sorry to say, but most school kids I teach for wouldn't understand this video at all

[@moldytaters4190]

Captain Raz Well dang.

[@cadenrolland5250]

Schools are not primarily concerned with teaching. If they were the boards of education, the Central Offices, and the whole educations system would be formed and run by teachers. Instead these powerful positions that actually call the shots go to bureaucrats, politicians, and business leaders, who then tell teachers what, when, and to a greater and greater degree, how to teach. Teaching a very nuanced sacred scientific art that is pretty much ruined by bureaucrats, politicians, and business leaders. If you learned the basics well, you need to consider yourself lucky.

[@officialsuperficial626]

I learned this material my 14th year of school in Physiology. You probably will to, kinda spoils some fun science videos though :/ The info you learn is fascinating af

[@moldytaters4190]

Ben Jay I love the basics, I was in advanced Science and Math 6th-12th grade. I only struggled with English. My school system is screwed up, because the way the teachers are allowed to teach just doesn't help the students.

[@keerthichandra376]

Nothing short of a gripping adventure thriller this one, kudos to the eontologists, the research team, the writing and production team and the presenter. You guys put together fantastic shorts about the ever so huge history of our beautiful planet. Always eager to see what you guys present next!

[@takeakiuemura3614]

My brain can't comprehend this concept because it's so significant

[@tomokinariyuki185]

安保徹も面白いですよ

[@plant5875]

cell exist mitochondria exist cell eat mitochondria mitochondrion produce energy cell is happy

[@jayce7646]

I knew what this was about, I had no idea the amount of depth she would go into. You’ve *earned* this thumbs up.

[@asiburger]

I remember learning this in Biology classes. It was awfully unstructured and carried little to no explanation on how things got together, what the differences are broken down to a simple level and just without alot of info around it. This right here should be mandatory footage for any school, since it is so comprehensive and easy to actually UNDERSTAND, rather than just learn a set ammount of random facts, without giving their meaning in the big picture. It was just so distant from any relationship with real life.

[@littlejackalo5326]

They always start with "two single called organisms..." and never explain how those organisms came about. Sure, one bacterium was engulfed by another, but where did the bacteria come from? They are extremely complex when starting off with nothing. Extremely complex proteins coming together to form enzymes that do extremely complex functions. Like DNA replication machines and flagellar motors.

[@sakshi2471997]

This is one of my most favourite stories of evolution. Absolutely love it!

[@thexalon]

I got to hear a guest lecture by Lynn Margulis at my alma mater in the early 2000's. She was brilliant and extremely clear about explaining all of this to an audience of mostly non-biologists.

[@rafaelalodio5116]

PBS Eons is one of my favorites chanels on KZbin, because you always make great content.

[@doubleirishdutchsandwich4740]

This is one of the best videos I have seen. You provide background information, then explain the idea, then you explain the empirical evidence for the idea. Beautiful

[@Neontronique]

This was another amazing watch. This is the video I would loved to have watched at school, rather than the crap I had to watch.

[@Psalm1101]

We cant make life in the lab what is the mechanism for this transfer and how symbioss is the answer we dont know to say this happened or this probably happened because this is what we have know is not s iemce protolife has not beenmade in the lab with computers bringing thelipids carbhydrates fatty acids in the lab has not been done not even proteins watch james tour

[@robertpryor7225]

I had to watch books, which are very boring

[@99bits46]

So if our ancestor cell had sucked in chloroplasts, we would we some badass solar panels today. such a shame

[@Suzaku455]

Salman Memehood if sea slug has told us anything it's not too late en.m.wikipedia.org/wiki/Elysia_chlorotica

[@L._.A-06]

Not really it is really inefficient to be “solar panels” plants grow slow because sun barely gives them enough energy to grow

[@dundee6402]

Salman Memehood Except movements would make the "solar panel" inneficient, therefore we would have evolved into... Well, plants

[@dundee6402]

Salman Memehood Also it sounds like an extremely bad idea where you would have to spend half your day at sun because otherwise you wouldn't get enough energy. Let alone at night and overcast days where you would be extremely sluggish because our fast metabolisms need a huge ammount energy

[@avinashsethu2499]

But we didn't able to move

[@joeys4289]

Finally a new video, FINALLY. I'd like to add that this is by far my favorite youtube channel, ever. I would watch this channel 24/7 and would choose it to be the only channel I would watch if given an ultimatum by aliens. Basically you guys rock ok. Now onto watching the video lol.

[@dipakyadav7473]

Agreed! And this is my favorite video of this channel.

[@TheIncredibleJumpman]

If you like this channel, you should check out the channel "Isaac Arthur". He's more focused on space themes but everything he talks about is very enlightening/interesting.

[@KingSquidicus]

Have you tried watching SciShow? That's another really great channel(s) (technically there are three. SciShow, SciShow Space, and SciShow Psych)

[@thefirstsin]

True

[@binky2819]

Sometimes I wonder if life is actually common in the universe, but it's just too rare for something like these 2 microbes fusing to happen. What if there's bacterial life all over the universe? Or maybe complex life is also common, but it's also all too rare for it to become intelligent. A lot of very specific things over a long period of time had to happen here on Earth in order for a group of tetrapods to become a self aware, planet dominating species (us). And a lot more specific things had to happen for tetrapods to even evolve in the first place.

[@ariochiv]

Considering that microbes existed on Earth for some 4 billion years, and more complex life only arouse a little more than 500 million years ago, and intelligence only arose a few million years ago, it seems reasonable to infer that even if microbial life is common throughout the universe, complex life and especially intelligent life are much more rare.

[@rewer]

I believe alien life that we discover would be in form of bacteria or virus

[@VVabsa]

binky2819 the universe itself is alot older than our solar system and planets. Life might more common than you think, but intelligent? When we look at the stars millions of lightyears away, we're looking too early at them or way too late to see them. I mean, the light we see from those galaxies shined propably a few million of not billion years ago.

[@juzoli]

binky2819 This fusion has happened 3+ times just on the Earth alone. It doesn’t seem like a bottleneck towards complex life.

[@mikeo759]

In a numbers game, it's "great filters" like these that lead me to believe that multi-solar system species do not exist in our galaxy, but may still exist in the universe. Most likely not within our reach to interact with.

[@kevincable4099]

Very thorough and well done video! Can't wait to share with my HS biology students since we have discussed this recently.

[@curiousfirely]

Kevin Cable I was thinking the same thing!

[@Immorpher]

Kudos for keeping the passion alive!

[@jiaqiniu2872]

Her voice is so soothing. She's my favorite narrator

[@leptyga]

Off topic: you guys have the best music of any edu-tube I know of. Who is responsible for this beautiful background?

[@thomtimm5537]

I disagree. The music in this video just annoys me. I don't know why but it distracts me from the content. Maybe it is just too loud.

[@a.modestproposal2038]

It has a teasing “surprise” backbeat that poisons focus on the speaker. What sadist engineered the audio for this segment? Unwatchable.

[@sriramthodla3104]

PBS Eons is amazing - very addictive even for a 40-year-old lifelong learner. She is especially good.

[@4675636b596f755954]

PBS Eons makes me wish I could 'like' whole channels.

[@ovicephalus5938]

Suggestions: Discussing relationships of major dinosaur groups? (Still controversial) How are arthropods and similar creatures related to other organisms and their superficial convergence with chordates? (Honestly kind of disturbing) Evolution of theromregualtion in synapsids? Evolution of thermoregulation in archosaurs? How plants fungi and animals are related and possible transitional forms? (I don't know if there are any) How sexual reproduction appeared? The confusing beaks we see all over the place in maniraptorans and ornithomimids?

[@bevobexley4087]

I love the awareness of the current internets, "as you may know from the internet, the mitochondria is the powerhouse of the cell" lol!

[@cinquine1]

You could have just said you don't like memes...

[@azrielmoha6877]

I just finished a biology exam with this very subject. Should've watched this video first

[@patricksarama4963]

*meanwhile 2 billion years ago while 2 cells were replicating...* Cell 1: “see you later alligator” Cell 2: “In a while crocodile” *2 billion years later...* Crocodile: “I told you we’d see each other again” Alligator: “Nice”

[@sent4dc]

Wow, you guys are my favorite channel. I knew that mitochondria was a "swallowed up" procaryote, but I didn't realize that it could've happened 3 times in the evolutionary history. Wow!

[@julioequinones]

This was a fantastic awesome super cool tremendous brilliant video!!!

[@viral_suppressor4154]

"You are also more physically complex than a procaryote, I mean, I haven't met you but I assume you are..." Her level of sass is over 9000... lol

[@philippe2072]

Could you do an episode on Terror birds or azhdarchidae ? It would be interesting, these subjects are missing on yt

[@eons]

Be sure to check back next week, Philippe! (BdeP)

[@liliaaaaaaaa]

Azdarchidae and the pterosaurs are my favourite birds. ✌

[@jpopelish]

Another important clue to support this idea of endosymbosis is the double membrane surrounding these organelles. It looks like single membrane covered organisms got a second membrane, as they passed through the membrane wrapping the host cell. That second membrane is an inside-out piece of the host cell, outer membrane.

[@klas666]

Right! It's such an unexpected thing (it was for me), but it's so logical!

[@jpopelish]

@@klas666 In effect, the organelles are still just outside of the cell they live inside of.

[@ArturoStojanoff]

Damn, I love this woman's voice. It's just so relaxing, it makes understanding stuff easier.

[@thetool96]

These videos on ancient life are simply awesome. Definitely Eons is my favorite channel.

[@ProfessorPolitics]

I remember hearing recently that there's a third branch, archaea, that are different from eukaryotes and prokaryotes. What's the difference between archaea and prokaryotes?

[@EvolBob1]

en.wikipedia.org/wiki/Archaea

[@MaestroRigale]

Archaea are prokaryotes, but are very distinct from bacteria. Eukaryotes include Animals, Plants, Fungi, and... uh... I can’t remember the others, I think the kingdoms have changed since I took biology. Protists? 😂😂😂

[@shelleysteva2251]

Their cell wall is made of different chemicals than bacteria. Most live in places that are too hot, too cold, too salty etc. For other species

[@vampyricon7026]

Prokaryotes include bacteria and archaea. Archaea include archaea.

[@ProfessorPolitics]

Thanks to everyone who's responded! This is definitely helping resolve my confusion.

[@idadelucia7779]

I'm in my 40s and these videos are more interesting than what I saw at school in the 80s.

[@KOTEBANAROT]

im just... in absolute awe that we are here. WE are here. thinking, feeling, asking questions. this is unbelievable.

[@phil0rms]

This video was particularly great. Thanks for your work, PBS Eons.

[@alysaronda]

Woohoo! Super interesting video. Thanks for keeping the content coming!

[@Bifocal_Burrito]

Only found this channel a day ago, already enjoying all the videos. Great stuff keep it up!

[@martijnbouman8874]

A small correction: the eukariotic cell did not originate from a small bacteria living inside a larger bacteria, but from a bacteria living inside an Archea cell. Bacteria and Archea are both classified as prokaryotes, but are completely differently build.

[@endofcentury7077]

"Can you hear it? Your mitochondria are calling out to you!"

[@feynstein1004]

I find it fascinating that the first eukaryotic cells gained enough of an advantage over prokaryotes that they managed to survive to date but not enough to drive the prokaryotes to extinction.

[@ThrottleKitty]

Want another fascinating thought? We consider ourselves top dog, but there are more bacteria in your gut then there are humans on the entire planet. We are basically walking bacteria cities! And when you get sick, that's the city being invaded, and when you get better, that's them winning the bacterial war!

[@KeegoonBarnacle]

Throttle Kitty But they don't have the gift of consciousness.

[@modolief]

And ... the prokaryotic (bacterial) cells in your gut outnumber the eukaryotic (human DNA carrying) cells in your body *ten to one*

[@feynstein1004]

+Throttle Kitty That doesn't seem very fascinating tbh

[@danielkorladis7869]

Consciousness could be considered a curse as much as a gift.

[@mXrtin100]

I love this channel ❤ makes all those tedious biology lectures back in school relatable

[@GenghisVern]

this was a very useful summary, thank you

[@carlw72]

We ABSOLUTELY LOVE PBS Eons!! Thank you so much for all the work you good folks put into it. Would you guy put the speakers name up on the screen a couple times during the video so we know who we’re listening to and a link to the behind the scenes crew as well? Thank you again!

[@Prelude610]

Question for another episode - how is knowledge, instinctive behavior type knowledge, passed along from generation to generation? Genetics sounds fine for the inheritance of structural characteristics, but does it also account for behavioral characteristics?

[@ThrottleKitty]

In short, yes, probably. We think so? There is evidence traumatic events can actually affect your DNA, and stress disorders can even be passed from mothers to children. We aren't 100% sure how it works, but DNA seems to store "The expectation of particular events" somehow. I wish I could tell you more.

[@Prelude610]

Thanks. I've heard versions of that, like how two generations after a starvation period offspring have a greater chance of being obese. I could definitely see something like that being passed along genetically. I'm really curious how more complex behaviors get passed along.

[@lexalina132]

Oooh, that’s an interesting question! OoO makes you wonder!

[@solalflechelles1216]

@@Prelude610 It's a very complex question, but basically, the neural networks in our brain come "pre-wired", that is, part of the layout of our brain is genetically encoded. That means that some behaviours do not need to be learned, because they are already present in our neural networks. A very simple example of such a behaviour is the stretch reflex, but theoretically more complex behaviours could be coded as well. It's very difficult to study though, because brain development, which explains how neurons form the first connections between themselves, is extremely complex. Of course, even if part of our brain's network is genetically encoded, the large majority isn't: there are about 1000 trillions synapses in our brain, which is way more information than our DNA could ever code for!

[@UlaisisP]

I'm so glad you did this episode, I asked for it and I got it (I`m not saying you did it for me, but who knows, maybe you read my comment and it started something). I think this is the greatest event in our life history (I only knew two events, and now I know it happened three times. You did a good job on this topic.

[@rebelbeammasterx8472]

Woah, green algae is like a "metaeukaryote." A cell within a cell within a cell, or a cell turducken, I guess you could call it "Perfect Cell."

[@LorgeDelta]

A correction is that Archaea are no more alike bacteria than they are to eukaryotic cells, they are in their own category altogether. Archaea have DNA bound with protein, not free floating like bacteria.

[@renocence]

Life can be so badass; sometimes.

[@mafarmerga]

I wish that she hadn't said "random act" at 2:13. It was driven by selection, the most decidedly NON-random part of evolution. Also one partner was a bacterium, the other was an archaean. Otherwise a pretty good overview of organellar symbiosis.

[@briandang6766]

This is some deep stuff

[@user-or7ji5hv8y]

These are really quality content. To the point and entertaining and instructive.

[@omarmartinezolvera8405]

this kind of videos always make me wanna cry lol everything is so simple, yet so amazing and perfect. Apparently "random" things that happened and changed the course of everything, it's just, how? why? and I just get flooded with existential questions until I click on the next video and I forget about it lol

[@lailahalmond4303]

LOVE PBS EONS!!!!!

[@GaryStark]

What an incredible story!

[@tirusew]

I really really love your style. You make everything interesting and understandable

[@lylecosmopolite]

Carl Woese, who discovered archae, was one of the greatest biologists of all time.

[@MrDlinch]

This is so beautiful, thank you for helping to understand connection between all living things.

[@maggsgorilla]

I love this channel. Please keep up the great work. I would like to understand more about evolutionary detail. I.E. it seems to me strange that early parts of evolutionary change provide no real benefit. I mean how did we get to eyes and wings and beaks a bit at a time. the first changes dont seem to offer much. Its not like avian dinosaurs could just suddenly fly, but the first mutation toward feathered wings seems irrelevant. I love your show

[@mnomadvfx]

" mean how did we get to eyes and wings and beaks a bit at a time. the first changes dont seem to offer much" The problem you are facing in understanding that outcome is that evolution of a new beneficial trait is all too often depicted as a strictly linear process in most media. Linear as in one germline develops one mutation, and then another, and then another with every few generations until it gets a significantly new trait. The reality is likely that a mix of positive (or negative) mutations met as multiple blood/germlines converged over time. Some mutations may have even been a negative to their originator on their own, but when mixed with mutations from convergent germlines may have provided a key component to a beneficial phenotypical trait. Another possibility is transgenic events where a virus picks up genetic material from one species or individual host cell and transmits that genetic material to a future host - we are always transcripting DNA to RNA to code for protein production so this could mix with viral RNA as it is replicating in a host cell.

[@ahmedalfatih7723]

When she said "so cute" that was so cute

[@catherine_404]

It's not like I didn't know most of this information, still, it's a great pleasure to see it all so neatly packed.

[@barnabasszabolcs8708]

Awesome content! (all of the series!) I didn't like biology classes but in this form... it's so exciting that I started to make a personal deep time line:))) mapping out things you talk about... this video, it makes so much sense, yet it must have been so surprising to discover when they did! Ah we live in awesome times thanksss!

[@Dragrath1]

A tantalizing part of the picture towards the origin of Eukaryotes might might involve the anaerobic Archaea only known via their DNA in organic samples that carry key genes for complex membranes otherwise unique to our nuclear genomes. Those are probably the best analogs for what the larger Archaean cell was probably like before combining with a bacteria that would become mitochondria . I wonder if the deadly threat of oxygen to anaerobes is what drove our Archaean ancestors to team up with aerobic bacteria giving little bacteria a nice place to hide from hungry microbes (or perhaps by chance one lunch managed to survive) which allowed the Archaean cells to venture out into the oxygenated world previously off limits an thrive. Has there been any new research on those "Asgardian" Archaea discovered only via DNA? Observing them alive might be what we need to finally come to understand how this happened.

[@SC-zq6cu]

Oxygen only became abundant after plant life appeared. According to what this video said this event happened thrice and the first plants appeared out of the second event. So, surviving oxygeneted atmosphere couldn't have been the reason for this, at least not for the first two events. I think this was mostly accidental but the pairs and triplets quickly flourished because of the additional energy benefits given by the "guests" that was unavailable to the loners.

[@tehguitarque]

I always loved learning about this theory in basic biology classes and beyond. Yet it was still fun to learn about it again here, and with some extra details and nice visuals!

[@FalbertForester]

Thank you for including references - something most videos overlook.

[@LamirLakantry]

Fun fact: Mitochondria is only passed on from the mother, not the father, so mitochondria DNA can be used to trace matroliniar ancestry.

[@AliHSyed]

WoohO!! Eons!

[@JeffSans]

one of my favorite channels too other than Kurzgesagt and this episode is amazing! keep making videos you guys!

[@suricatakat6476]

Excellent episode. Um, however the music seemed to be drowning you out, which makes it a strain to concentrate on what you're saying. Just thought I'd mention it...

[@ThereIsNoGodOnlyUs]

This channel is seriously amazing.

[@christopheb9221]

This makes me wonder if genetic editing of mitochondria could benefit us

[@batsrcuter]

Thank you! Not sure if it was the request I made two weeks ago for this topic but well done. Will be adding it to my history of earth prezi for next year.

[@greensteve9307]

Great vid!

[@kwjames87]

All of these have been really good, but this one was really really good.

[@Atchitchi]

Perfect timing for this video, i was trying to explain something i read ( www.cell.com/cell/fulltext/S0092-8674(17)31504-0 ) to someone and had to use mitocondria as a kind of analogy... btw, how about a video about virus :D

[@modolief]

6:34 -- Fascinating! That yet a third type of eukaryote arose only about 450 million years ago, beyond the first occurrence of endosymbiosis giving rise to mitochondria, and the second, giving rise to chloroplasts. I hadn't known about this group before!

[@TheRedKnight101]

That is referred to as secondary endosymbiosis as the Stramenopiles (groups including brown alagae, diatoms, and Plasmodium (malaria)) took the chloroplasts from red algae and there are even cases of tertiary endosymbiosis in dinnoflagellates. Even euglena is believed to have to taken it's chloroplast from green algae.

[@modolief]

Wow, fantastic info, thanks!!!

[@adamjass7258]

please do a video about the Cambrian explosion

[@ringoffire0]

they already did

[@field4133]

Awesome video! I can't get enough of this channel and the host is wearing such a great outfit in this one!

[@perrysanders2899]

I would like to know when did amphibians develop

[@austinmays2492]

That music was amazing. Is always is on Eons. I think that was a great episode. Taught me more than by biology class did

[@Halberdin]

The music is so distracting that I stopped watching.

[@marklandgraf7667]

+Halberdin Agreed

[@guillermojrboy3292]

Speaking of gut bacteria, how do newborns get theirs?

[@olbap4683]

From mother and environnement.

[@negative.infinity]

I remember some article or video which said this comes from their mother breastfeeding them. For the longest time, people were puzzled by this because we cannot digest the breast milk ourselves. Then they realized that these gut bacteria can. The breast milk wasn't feeding us, it was feeding these bacteria and helping them to get established.

[@regular-joe]

Also, from exposure while moving through the birth canal. Infants born by cesarean section are severely lacking in beneficial gut microbes and it can affect them their whole life.

[@ChipZilla69]

Longer videos please. Thumbs up

[@perrysanders2899]

Love this channel. Keep up the vids. Endosymbiosis!!!! I am guessing it is the mitochondria and chloroplast because i learned that in APBio

[@perrysanders2899]

I guessed correctly

[@thenavig8r956]

Wow, most excellent explaination to date. Love your humor. David

[@phytoplanktonpete]

Endosymbiotic theory!

[@davids.8509]

Thanks little guys for being friends instead of eating each other.

[@hansrudi5551]

i've heard that today no new coal is produced, could you explain why?

[@scottk3034]

Isn't peat one of the first steps on the journey to coal?

[@CorwynGC]

Most coal came from plants between the point where they started producing lignin (the glue that holds plants cells together allowing large plants), and the time when fungi evolved a method of eating it. During that time wood basically didn't biodegrade, leading to large deposits.

[@modolief]

When it was new on the scene, dead wood didn't decay. Ok. So ... will there at some point be critters that eat plastic?

[@CorwynGC]

Yes. That time is now. en.wikipedia.org/wiki/Nylon-eating_bacteria

[@bo_392]

see their other video, "History's Most Powerful Plants".

[@lewistempleman9752]

That's just lovely

[@firstcynic92]

Quick question after seeing the first 20 sec of the video... Will you say "The Powerhouse Of The Cell" during the rest of this?

[@firstcynic92]

Yup she did.

[@charliele8175]

Woooo! New video! Love this channel.

[@Wickedali1127]

Prokaryote is an outdated term. The distinction between prokaryote and eukaryotes as you describe is rather arbitrary. It is better to sort by domain, bacteria, archaea, and eukarya. B.S in Microbiology

[@mericusta1988]

Perfectly balanced introduction, told in great order and with passion. Thanks

[@Suprsim]

Sweet video

[@raffianmoin1358]

bacterium 2: mom,i'm gonna sleep over my friend bacterium 1's house. ........... Multicelled organisms.

[@golgarisoul]

I would like some chloroplasts in my cells.

[@Imadurazno]

Cypher Caliban One chloroplast please ☝️

[@danielkorladis7869]

But I hear that it isn't easy, being green.

[@robertab929]

There was even additional endosymbiotic step in appearance eukaryotes before getting mitochondria: *An excavate root for the eukaryote tree of life* This work is about the appearance of first eukaryotes based on genetic analysis of genomes from many groups. *Two endosymbiotic events are proposed,* the earlier most likely involving a γ- and/or δ-proteobacterium (γ-/δ-proteo) and the second an α-proteobacterium (α-proteo). *The second event started the existence of aerobic mitochondria in eukaryotes.*

[@lefthandofdog]

I love the show, guys, but I really gotta be honest about something. In that one transition slide where it zooms in on the dinosaur, it zooms right into the dino's butt.

[@Imadurazno]

Braedon Merwin Thanks for that

[@danielkorladis7869]

I assume that's intentional.

[@nalloastro6353]

This channel is amazing