Two lifeforms merge in once-in-a-billion-years evolutionary event | Hacker News Reader

Two lifeforms merge in once-in-a-billion-years evolutionary event

newatlas.com

291 pointsawb108 comments

> The first occurred about 2.2 billion years ago, when an archaea swallowed a bacterium that became the mitochondria. The second time happened about 1.6 billion years ago, when cells absorbed cyanobacteria that became chloroplasts.

How was it possible that I could take 3 years of high school biology and not have heard that one lifeform absorbing another lifeform was responsible for these amazing new capabilities? We learned about mitochondria and chloroplasts, but in a very dry way. Primary education could be so much more interesting to kids with context like this.

Possibly you took biology before this was well known? I think they just have that mitochondria theory from the fossil record and DNA matching between current eukaryotic life.

The idea (Symbiogenesis) dates back to the start of last century, and it was a common idea by the seventies. Curricula can move slowly, but I’d expect that it would have been taught in the eighties.

Then again it’s evolution, no way around it, so I can imagine some teachers and schools might omit the theory.

You need some pretty advanced genetic and phylogenetic work to put meat on the bones of the theory though and that happened recently

I am not sure from what point of view you are saying that, but I came across an interesting twist to that.

Some years ago I read a fascinating book about evolution, mostly explaining things that do not get taught in school. No surprise there is a lot - school level teaching in any subject is usually simplified and incomplete so not entirely accurate compared to what researchers in the field are studying.

There was an interesting, and disturbing preface. One of the authors said his colleagues tried to persuade him not to write the book, because explaining to a wide audience that what they were taught in school about evolution was a simplified approximation (essentially obsolete) would encourage creationism. I thought at the time that this was both unethical and likely to backfire.

As I said in another recent comment, a creationist I know recently sent me links to arguments for creationism on the Jehovah's Witnesses' website, and they did precisely this. Quote from research to show people what they were told was false.

If you are not truthful people will not trust you, if people in a field are not truthful people in the field loses credibility in the eyes for many people. How difficult is it to tell kids that they are being taught a simplified version, and here is a rough outline of the complexities, but it is beyond what can be taught at their level?

I see similar things all over the place, with well meaning people pushing bad evidence for things (e.g. climate change). Same problem when people realise an argument is flawed, or a particular theory or model is flawed, they assume all arguments are flawed.

What was the book?

I cannot remember. I borrowed it from a library and never bought it.

All I can remember is it had two co-authors, neither of whom was famous.

I would be very happy to find it as I regret not buying a copy.

In that same vein, take a read of: https://jsomers.net/i-should-have-loved-biology/

This is great, thanks for sharing it! I think it would be good fodder for HN discussion so submitted it to /new, hope you don’t mind.

Thanks for that. Here’s a link for those following along:

https://news.ycombinator.com/item?id=40103590

I'm not sure either. Public school's primary purpose is to teach you just a few things:

1. The mitochondria (the powerhouse of the cell)

2. You're made up of DNA and everything is atoms with electrons that zip around on little orbital paths

3. Stalactites vs. stalagmites

4. Crocodiles vs. alligators

5. The Holocaust was seriously bad

6. World history consisted of the US revolutionary war, the Civil war (fought over ending slavery), the Great Depression, the New Deal, and the Western Front in WWII (which began in 1941 and ended in 1945)

You were probably looking out the window for a few years when they continually announced that the mitochondria (POTC) was an absorbed bacterium.

Experiences vary. I learned the entire European enlightenment, french, college Calculus, Marching band, percussion, College chemistry, college English. In fact, once I got to college I took only chemistry courses (my degree), 1 calculus course, 2 years of German, and 3 philosophy courses. The german was bullshit requirement, frankly, and I should have taken french to simplify my life. But I was young and naive.

If you took french, all you'd have learned is a different way to pronounce a lot of english words.

By taking german, you learned how to take little things, and turn them into lengthy monstrosities.

When you have 25 overstimulated kids and 45 minutes and an underpaid teacher, it's just impossible to make it interesting.

I mean there are so many amazing things like ATP generating machinery, how flagella move, ribosomal walking etc. You don’t have to post a cheap, lazy, cynical comment like this, there’s a lot to learn and only so much time to do it in.

Clearly you are curious about this stuff, so it would be easy to teach you about it.

Not everybody is so eager to learn biology.

My bystander’s understanding: curiousity is the key factor distinguishing between “good” and “bad” students (as measured by grades)

> You don’t have to post a cheap, lazy, cynical comment like this, there’s a lot of learn and only so much time to do it in.

It helps to keep in mind that you're replying to a user who voluntarily named themselves anal_reactor

Actually it’s possible (idk if he was underpaid) though I had a science teacher who is an extremely rare person. This is his website.

http://boomeria.com/

The teachers make more than I did for most of my life. Is it not possible for them to take personal responsibility without having to provide excuses? Most teachers do not want to be teachers and are just there because they couldn't make it in their own field or just prefer to do less skilled work.

I disliked many of my teachers but this is still a pretty rude generalization.

Seems like you are answering the first part of your question with the second part

These aren't excuses, but observations.

I've taught in classes of 12 and of 32, the differences in students' behavior, and in reaction my own was huge.

Similarly, I've taught classes where students just came back from an hour of PA and classes that were the second class of the day. The former group of students had always trouble concentrating and focusing, whereas the other group would sometimes have trouble getting up to steam in many activities.

Similarly, I've taught classes that were obligatory for students and classes that were electives. Again, the differences in students' behavior was quite pronounced.

Given constraints and practicalities of our educational system, it is difficult to offer each student the best courses, activities, support, etc. they each individually need. Instead, you often end up compromising. Which isn't great. Particularly for students performing above or below average compared to their peers.

Anyway, just a frustrated ex-teacher here. Thanks for listening.

Most teachers are kids who go to college at 18 with no idea of what they’re capable of, who spend a pile of money to be a teacher because of idealistic principles inside them combined with an interest in teaching. They are certified, highly trained, and even highly specialized for their grade level and content.

Teaching isn’t a field littered with people who failed to launch elsewhere. The four to six year college barrier to entry (that’s four to six years of teacher focused classes, in person unpaid internships and full time unpaid student teaching that ranges from 3 months to more than a full year of unpaid full time work in a classroom as a teacher, certification testing, etc) all for a job that is critically underpaid and unappreciated, attacked both by the children in the school, and by people like you who tell them their noble decision to dedicate their life to educating your children means they’re a failure or a loser in some way. That isn’t something a “failure” is going to chase.

These teachers achieve a bachelors level degree (or higher) in education, are specifically trained teach through a multitude of specialized classes, have to spend upwards of a year doing completely unpaid in person full-time internships, and are as highly trained and educated in their field as any college graduate who achieved a bachelors or higher.

Most teachers cannot afford to live in the communities they serve with current housing and rent prices. The current state of education funding and school overcrowding means many of those teachers who put their heads down and soldier through are coming out of pocket with hundreds or even thousands of personal dollars just for basic school supplies like paper, while teaching class sizes that have ballooned to unreachable levels. I had classes with more than 40 students in a classroom that seated 38 max.

“Couldn’t make it in their own field.”?

Teaching IS our field, and the things that are killing our education system are not teacher-lead.

Maybe stop spouting nonsense and go look at a school. The young teachers are bright eyed idealists with tens of thousands in student loans who are fresh off bachelors degrees, and the old grizzled teachers are the young ones who survived and stuck around - they have been doing their job for literal decades. The places you find uncertified teachers (the human beings you’re denigrating) working in classrooms are usually the extremely underserved, underpaid, and desperate schools and communities and states where it’s extremely difficult to find any certified teacher (like a rural town with high housing prices, nothing in town to rent at a number a teacher could afford, and a sub-$40,000 starting wage for teachers in the year 2024).

My only regret is that teachers failed to teach you to recognize the Fox News style propaganda you’re regurgitating. Bashing teachers does humanity no favors. We should strive for livable wages, functional safe workplaces, reasonable commutes, and affordable housing for all workers, regardless of career, because a functioning society needs all of us, from doctors to burger flippers, and especially teachers.

I skimmed this in ~5 seconds. I'm not going to engage with someone who thinks "Fox News style propaganda you’re regurgitating" is a valid criticism.

When bacteria die, their brethren will literally absorb the DNA of the fallen and obtain their abilities. Bacteria are the Mega Men of microbiology.

https://en.wikipedia.org/wiki/Transformation_(genetics)

Oh you evolved a new antibiotic resistance mechanism? Now I've got your power.

I’ve had the same experience. Biology in school was boring and static, whereas today I can get lost reading about obscure biological phenomena on Wikipedia.

You can hardly blame the school for that though. As others have said, it's not possible to cater to every student's interest and ability, so compromise has to be made and consequently things turn uninteresting.

Also, there's some confirmation bias and survival bias here. You won't read something that's boring and static to you, or you don't bother remembering reading/watching them. Whereas if something wakes your interest, you'll likely to explore further. At school, you were forced to learn things regardless of whether you might or might not like.

Also, 'you' of today is not the same 'you' back at school. You're now much more experienced and knowledgeable than before. So reading, understanding things are easier than at 15. It's like learning a new language, at first it is challenging because you know only a handful of words, but as you learn more, it gets easier. You know where things are in the big picture and they become interesting.

My point was more that these obscure bizarre biological phenomena are never covered in high school biology classes.

It wasn’t on the AP test.

(Put it there and you would have learned about it, because tests define curriculum—either immediately or downstream)

It was probably mentioned in the textbook and you just forgot. I just checked my textbook and it’s one of the first things they say when introducing mitochondria and chloroplasts.

I remember we learned this about mitochondria and chloroplasts in 10th Grade Biology back in my day, but I think if I quizzed anybody I went to high school with today it would be a coin flip as to whether they remembered that as part of the lesson. I mean, it's probably a coin flip on any piece of information from when we learned about organelles, or if they even remember the word "organelle". If you quizzed me, I couldn't have told you approximately when these events happened without the article in front of me even though I'm pretty sure we covered that too.

100% of my former schoolmates would probably remember the "powerhouse of the cell" meme though.

I believe the word "organelle" is a part of passive vocabulary of many reasonably educated people. Non-biologists would probably fail to quickly come up with a single word to mean any specialized part of a biological cell but would probably understand when they meet this word used by someone else.

Maybe? I’ve thought the same about a lot of things covered in the school’s curriculum with former schoolmates or people who went to the same schools in the same district around the same time with the same curriculum; but over the course of my adult life I’ve heard variations of the question “why didn’t we cover this?” about some piece of information (including specific vocabulary) about some subject or another that was covered and I clearly remember being in the textbooks that were used district-wide. Among friends at least I’ve long ago stopped answering that question with “actually, we did”.

People just forget a lot of what they learned in school, but if you re-teach them it might jog their memory of the first time they learned it… or it might not. Pretty much a coin toss.

Quite obviously, almost nothing will stick if simply mentioned/explained just once or twice during the schooling process. Its usage has to be incorporated into the process kind of like when you learn basic algebraic formulae and then apply them countless times during the years to come so they become a thing as ordinary as your own hands. You can still forget precise correct formulae after some years of non-usage but you will never forget they exist and you will always know you have to look up or derive a specific formula once you encounter a relevant problem.

When did you finish school?

trust me- there are lot of things that are barely mentioned in high school, also curriculum is not updated as often as the science uncovers something new and biology is moving forward with a break neck speed at the moment, imo.

Like, you couldn't learn about CRISPR editing before 2000.. because it was not there then. Now it's common knowledge.

Depends when you took it. The endosymbiotic origin theory has links being worked out well into the 2000s.

https://www.nature.com/scitable/topicpage/the-origin-of-mito...

Symbiogenesis of mitochondria substantially pre-dates the 2000s. It was first proposed over a century ago, 1905 and 1910 by Russian botanist Konstantin Mereschkowski, and substantiated with evidence by Lynn Margulis (a very substantial evolutionary biologist, also one of Carl Sagan's wives) in 1967.

<https://en.wikipedia.org/wiki/Symbiogenesis>

Mitochondria were sufficiently established in general awareness to be a plot point of Madeleine L'Engle's A Wrinkle in Time, being a concept which fascinated the character of Charles Wallace Murray, a young prodigy, in the stories. Though I don't recall if symbiogenesis is specifically referenced. The first story in the series was published in 1962.

Sure but when it was taught in the 2000’s, it was always done with a big caveat about how the theory was still being debated. In hindsight, all previous mentions will seem like substantiated and obvious statements but there’s a reason articles about it are still coming out today.

I'm not an area expert, and of course don't know what you were taught, or even what general pedagogy over recent decades has been.

I suspect that strong confirmatory evidence came through awareness and analysis of mitochondrial DNA, a term which begins apppearing in Google Ngrams as of the 1960s. Full DNA analysis likely wouldn't have occurred until the 1990s or early aughts, when full genome sequencing became available, so the point might have been argued until then. It strikes me as a rather rear-guard objection at that point however.

(I'd tried a few times to make a clearer assessment of when the view became mainstream, with inconclusive results, though "proposed in the early 20th century, largely substantiated in the 1960s, and all but sealed by 2000" seems a fair statement.)

We don't teach theories in primary and secondary education when they are first proposed though. And don't come at me with the Wikipedia summary intro paragraph sir — Margulis started promoting the idea in 1967 with a theory paper, she didn't substantiate it with new evidence. It required the genetic evidence later decades would bring to really substantiate.

And yes, no one has questioned the existence of mitochondria for a good long while now.

2.2 billion years ago, and then again 1.6 billion years ago = once in a billion years event?

Did you learn in school that mitochondria had its own DNA? And that our mitochondria comes from the egg, so mitochondrial DNA always comes from our mother's mitochondria.

Or even played Parasite Eve [0]

[0] https://en.wikipedia.org/wiki/Parasite_Eve_(video_game)#Plot

Actually, yes. I recall that the high school textbook and lecture did talk about mitochondria having its own DNA and that mitochondria traced the maternal tree. Although those are somewhat interesting, its origin as a separate lifeform is WAY more interesting.

If this is exciting to you, I’d recommend “Power, Sex, Suicide: Mitochondria and the Meaning of Life” by Nick Lane [0].

It’s a fascinating and captivating (albeit dense) exploration into the concept that mitochondria were central to the success of eukaryotic life. I read it in a book club during my PhD.

[0] https://nick-lane.net/books/power-sex-suicide-mitochondria-m...

The first symbiotic event was a million times harder than the 2nd or the 3rd. The first time the host had the extremely hard task of dealing with any DNA and RNA produced by the guest during it's life and death. The host had to evolve stuff like a cell nucleaus and sex to live through it and alternative splicing to deal with the fact that all it's genes were damaged by selfish genetic elements that came from the guest. Integrating any later symbionts is still hard, but not nearly as hard.

It's possible that the first symbiosis that let to the origin of the eukaryotes is not a one in a billion years event, but one in a trillion or one in 10^20 years or ever rarer. That is it may be that in a billion planets with simple life forms only one "creates" complex life like animals. It can be the great filter that leads to the Fermi paradox.

> It can be the great filter that leads to the Fermi paradox.

I'm increasingly of a similar view — that the great filter is something we're already past, due to the incredible combinations of constraints that led to where we are today.

Another infinitesimal probability may be the development of abstract intelligence. The conditions that led to our brand of intelligence being an evolutionary advantage seem particularly unique: https://www.ncbi.nlm.nih.gov/books/NBK210002/

Good one, I'll have a look. Are there any good videos on YouTube on the topic of origin of intelligence? I can't seem to find any.

Wish I could recommend one but I don't frequent YouTube, sorry!

I feel there might be intelligent species out there without either the resources to develop technology or the ability to do so. Sharks could become smarter than us one day, but without thumbs they aren't going to succeed in overtaking the planet. Similarly, there could be a humanoid fish species under thick ice sheets of Europa, and they would never guess there is anything more than their "ocean" in the universe.

Orcas have impressive brains:

https://en.wikipedia.org/wiki/List_of_animals_by_number_of_n...

The headline makes it sound like this happened last week, but it actually happened 100 million years ago, and we're just now discovering it.

It could have also happened last week.

wow and I just bookmarked this in the News folder

It's still news to you...

100 million years ago is pretty much the equivalent of last week on an evolutionary timescale.

Only if you are a 45-week old baby

Perhaps 100,000 years is a better analogy for a week in evolution. A lot can happen in 100 million years of evolution. The boreoeutherian ancestor, that is the ancestor of all humans, rodents, carnivores, cetaceans and more was alive roughly that many years ago.

Ah, thank you, I was suspicious thinking what are the chances they would just happen to be watching something microscopic when such a rare thing occurs...

So, since the article didn't mention it, presumably nothing interesting happened as a result? Yet?

The article specifically says it likely happened 100 million years ago and that the interesting thing is an organelle that fixes nitrogen. That is a big deal, on the order of photosynthesis. A lack of nitrogen-fixing organisms is an extremely common cause of desertification; e.g., it's why industrial farming requires fertilizer, and a major reason why once a forest is clear-cut you'll only get one more generation of trees.

Eh, it's not like it was an instantaneous event. If the symbiotic relationship first began developing a hundred million years ago, it may have taken the bacteria all this time to get to the point where they're now – organelles that are now fully dependent on the host algae cell.

Ah, that's a relief. It sounded incredibly scary if it was some new type of species just now. I would imagine that it would overwhelm our ecosystems wreaking havoc until a new balance is eventually found with new winners and new types of species dominating our environment.

Check out the algae in question: https://en.m.wikipedia.org/wiki/Braarudosphaera_bigelowii

It surrounds itself with twelve pentaliths, forming a perfect dodecahedron! This is such an incredibly cool organism.

Wow it looks like something out of stargate. Hard to believe that it’s natural and organic with such sharp edges.

In other words, it has a D12 exoskeleton.

Also cool-looking are Volvox.

Diatoms generate a silicon dioxide skeleton and they look like little space probes.

https://paleonerdish.wordpress.com/2013/06/10/an-introductio...

https://www.mediastorehouse.com/science-photo-library/diatom...

Primary sources:

[1] https://www.cell.com/cell/pdf/S0092-8674(24)00182-X.pdf

[2] https://pubmed.ncbi.nlm.nih.gov/38603509/

There's also a press release from LBL:

[3] https://newscenter.lbl.gov/2024/04/17/scientists-discover-fi...

[1] is open access.

What's more likely, it happens once in a billion years and we happened to catch the exact specimens doing it? Or it happens a lot more often and we happened to catch an instance of it, but it's usually not as impactful or memorable as the mentioned instances?

Terrible sensationalist reporting.

> Altogether, the team says this indicates UCYN-A is a full organelle, which is given the name of nitroplast. It appears that this began to evolve around 100 million years ago, which sounds like an incredibly long time but is a blink of an eye compared to mitochondria and chloroplasts.

It happened 100 million year ago, not in the petri dish at the lab.

It really has only happened a few times in the history of life, at least only a few times that survived. The title could use a little work though.

This particular instance started 100 million years ago, so it's not a right-place-right-moment situation.

There are only two known instances of symbiogenesis occurring, mitochondria and plastids (which includes chloroplasts), which justifies the once in a billion years description. Other instances are suspected. https://en.wikipedia.org/wiki/Symbiogenesis

There are lots of known endosymbionts, separate organisms living inside the body or cells of another, a prerequisite for symbiogenesis. https://en.wikipedia.org/wiki/Endosymbiont

Hmmmm, I don't know if I buy their claim of primary endosymbiosis being so rare.

Almost all insects have heritable endosymbionts. https://doi.org/10.3389/fphys.2013.00046

That's a different meaning of endosymbiosis at a more macro scale. This is cellular endosymbiosis. Having bacteria in your gut is not the same as having them be integrated at a molecular level into your cells as an organelle. You're scepticism of the media hype claim is correct though, there are other well known examples of endosymbiosis like this occurring, primary and secondary. Perhaps not primary with cyanobacteria but thats hardly some huge "scientific leap" in understanding or astonishment compared to some of the other stuff we know about.

Ironically you do see this kind of cellular endosymbiosis amongst the endosymbionts within insect guts with the most extreme example probably being Mixotricha paradoxa https://en.wikipedia.org/wiki/Mixotricha_paradoxa

Hatena arenicola https://en.wikipedia.org/wiki/Hatena_arenicola is very similar to this new finding, but with an algae instead of a cyanobacteria so its a secondary endosymbiosis which if anything is actually more interesting and bizarre.

We also know from the genome of Smybiodinium that its undergone quite a few endosymbiotic capture events some secondary with algae but quite likely some primary with bacteria too https://en.wikipedia.org/wiki/Symbiodinium

Witness the power of dependency injection

:facepalm: :)

git submodules

But this is vendoring.

Arguably a better source was posted here https://news.ycombinator.com/item?id=40101317 but no discussion there

Favor composition over inheritance.

Maybe just bad article or I'm not fully getting it... So when this algae reproduces, do the offspring contain the new organelle? Article mentions something about dumping old DNA, but does it incorporate the DNA of the bacterium in the process? Not a biologist by any stretch

Yes. The organelle replicates with the host cell. As time goes on more and more of the bacterium’s DNA involved in separate survival outside the host just goes away as it further specializes in its task and leaves the rest to the host cell.

Chloroplasts and mitochondria had the same kind of beginning.

If I understand your question correctly, the cell devision figure directly addresses it (the answer is yes).

Here's an interesting video about a type of Maize that can also create its own "bound" Nitrogen https://www.youtube.com/watch?v=CFyd-kC6IUw

Nice. We'll have to check back in 10 million years to see how it went.

It happened 100 million years ago.

> It appears that this began to evolve around 100 million years ago, which sounds like an incredibly long time but is a blink of an eye compared to mitochondria and chloroplasts.

From the title, I assumed they saw the genius of this extremely rare event. Very new in terms of life on Earth, but not something that first happened this year.

Who new science could be so humorous: "Imagine if kidneys were actually little animals running around, and humans had to manually filter their blood through a dialysis machine. Then one day some guy somehow gets one of these kidney critters stuck... Internally (who are we to judge how?)"

Isn’t the placenta an example of this? https://whyy.org/segments/the-placenta-went-viral-and-protom...

I passed high school biology with a C, but I think the difference here is that two completely distinct independent organisms merged into one. The mammalian placenta seems to be more of an example of animals appropriating genetic code from viruses, which I suspect is something far more common in evolution.

No, it's derived from a virus, not an independent living organism. 8% of human DNA is derived from viruses that infected our ancestors and inserted themselves into our genome in order to replicate (which usually isn't passed on): https://theconversation.com/humans-are-8-virus-how-the-ancie...

Seems the N2-fixation is limited by CO2-fixation. Be a bit weird if it wasn't and they sucked all the N2 out of the atmosphere. Atmosphere would get a bit spicy and flammable.

Why? Partial pressures are what matters. If N2 was sucked out of the atmosphere, not much would change.

https://space.stackexchange.com/a/5694/14420

I worked for NASA. That answer is wrong. The ISS and Space Shuttle have standard 15 psi atmosphere for abort-to-Earth situations, not for any reasons related to fire. A 3 psi oxygen atmosphere has exactly the same fire risk as a 15 psi atmosphere with inert gas making up the rest. Chemically, partial pressure is all that matters. Apollo 1 had an over 15 psi pure oxygen atmosphere.

[dupe]

More discussion: https://news.ycombinator.com/item?id=40011438

If other plants get in to this ability it could revolutionize agriculture. Also, will tank the fertilizer industry.

Well not far when plastic will be part of your blood stream and new organisms will eat it as well

The Cell paper uses the heading "Summary" rather than "Abstract". When and where and why did that change? I don't see it in other papers and in other links for this paper. Maybe I don't read Cell enough?

Reply on news.ycombinator.com