Strange, tentacled microbe may resemble ancestor of complex life | Hacker News Reader

Strange, tentacled microbe may resemble ancestor of complex life

science.org

96 pointsrbanffy21 comments

OT but a pretty filthy dark pattern for the cookie banner on science.org - as I went to dismiss their newsletter popular on mobile another one (presumably the ‘allow cookies’ popup) quickly took its place so I’d click it.

Stuff like this really puts me off a site

This article linked near the bottom is pretty interesting w.r.t. the origin of eukaryotes. IANA biologist, but it seems to make a pretty good case that taking on mitochondria led directly to a lot of the other eukaryotic complexity. I wasn't previously convinced why it couldn't have gone the other way. https://elifesciences.org/articles/81033

This is the thesis of the book “The Vital Question” by Nick Lane. It’s a pretty interesting read. At points the book was slightly beyond my reach in comprehension but I still enjoyed it.

One fact that still blows my mind is that into the 1990's, there were something like 12,000 known prokaryotic species, and microbiologists estimated anywhere from 100,000 to a million were still undiscovered, since they didn't like to grow in a Petri dish. But with the advent of PCR based techniques, that number grew to one trillion. Not only whole new phyla but two entire new branches of life (DPANN and CPR) were discovered in the early 2000's gold rush, and microbiology and mycology are still struggling with how to classify and organize these organisms, along with foundational questions like what 'known species' even means. It's a pretty cool time to follow those fields.

tl;dr we failed to notice 99.999% of life on Earth until about twenty years ago.

> A recent estimate of the global number of prokaryotic species is 2.2–4.3 million [110], down from previous potentially flawed estimates of trillions [111]

From this Nature article: https://www.nature.com/articles/s41396-021-00941-x

See the cited paper by Locey and Lennon (https://doi.org/10.1186/s13062-020-00261-8) for a counterargument. The issue comes down to mathematical modeling of biodiversity and microbiologists are fighting about it. The fact that dozens of new phyla and two entire branches of life were discovered in the past 20 years is not disputed by either side.

A good backgrounder on this topic is "Assessing the global phylum level diversity within the bacterial domain: A review", https://doi.org/10.1016/j.jare.2014.10.005

TIL a salt water spring at -5C temperature exists (and extremophiles live in it):

https://en.wikipedia.org/wiki/Axel_Heiberg_Island#Lost_Hamme...

Fascinating! Is the way these new groups mess with their genetics different enough from the rest of Earth’s life to require another shift in how we classify them? “What ‘known species’ even means” points to maybe yes, but I’m not versed in genetics and just found out about these groups from your post.

It’s only been, what, 20 or 30 years since our ability to look at genes started really shaking up taxonomy and yielded “the phylogenetic tree.” I wonder what studying these tiny weirdos will teach us about what we still don’t know about our own more stable branches.

One of the groups (DPANN) is I believe invariably symbiotic, which made it hard to find through traditional methods. It may shed light on how eukaryotes got started.

A kind of fascinating problem in microbiology is that prokaryotes didn't take high school science and don't realize you can't acquire traits, you can only inherit them. So they trade genetic material with each other like Pokemon cards in a process called "horizontal gene transfer". This makes it considerably harder to figure out what 'species' even means.

Is there anyway to know what the actual ancestor looked like? Thanks to HGT isn’t it pretty difficult to determine when a gene entered the ancestral line?

Probably a mini Cthulhu or something

So, instead of Great Old Ones, we have Tiny Old Ones.

HGT?

Horizontal Gene Transfer, possibly?

Yes exactly

Horizontal Gene Transfer. Bacteria pass useful genes to one another. think of it like a weird and simple form of talking: if a bacteria enters a new environment and meets other bacteria it “asks” the bacteria in the new environment for useful genes. I’m definitely not doing this justice but it’s fascinating.

Anyway our high level understanding of mammalian/plant evolution (or the ability to go back in time from it) doesn’t quite apply to bacteria.

I finally start to see a clear story in the evolution of cell types to complex life. Are there valuable adversary/competing hypothesis?

Those aren't tentacles; tentacles are motile.

Me: “Grandpapa, is that you?”

Tentacled microbe: ::Cthulhu noises::

Flying Tentacle Monster ?

Yeah, but also is sort of one of the Old Ones

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