The First Animal Ever Found That Doesn't Need Oxygen to Survive | Hacker News Reader

The First Animal Ever Found That Doesn't Need Oxygen to Survive

sciencealert.com

165 pointsgeorgecmu58 comments

It says that they don't have mitochondrial DNA anymore, and that they can survive in very low oxygen environments....but neither of those is the same as "not needing oxygen". Parasites lose a lot of machinery that they use the host for (such as digestive tracts).

Not needing oxygen would mean a pretty dramatic shift in a whole lot of biochemistry. Maybe that's exactly what has happened, but from this article, it sounds more like they evolved to tolerate very low oxygen, and also they use the host for a lot of necessary functions (common in parasites) and so have lost some unnecessary complexity.

No, it addresses that point. Paragraph 7 acknowledges it. Needs no oxygen at all.

No, that is referring to other organisms. It neglects to mention how this particular one survives.

No what?

Paragraph 7 acknowledges what the parent comment mentioned, that other species use very little oxygen.

The title says this one needs none. The 2nd paragraph says:

“…it doesn't breathe; in fact, it lives its life completely free of oxygen dependency.”

If that’s not enough, it’s also made clear in Wikipedia:

https://en.m.wikipedia.org/wiki/Henneguya_zschokkei

Yes indeed, other species, as per my comment, but it doesnt mention how this species does it.

Phenomena are discovered first, mechanisms later

There have been plenty of eukaryotes found earlier, including multicellular metazoans (animals), with anaerobic metabolisms. They have organelles called hydrogenosomes, which are thought to have convergently evolved from mitochondria. So, I call bullshit on the title.

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

Yes I think it must mean multicellular organism. I understand there are lots of unicellular organisms that don't use oxygen.

Even with that proviso it's still wrong. These animals were found in 2010 to be living in a completely anoxic environment with 2.9 mM of sulfide(!).

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

Lines up with this Nature 2010 article "Animals thrive without oxygen at sea bottom (Creatures found where only microbes and viruses were thought to survive.)"[0] which I don't have access to.

[0] https://www.nature.com/articles/464825b

Searching for YouTube videos of those anoxic, salt, toxic "brine lakes" is highly recommended. An alien sea within our oceans.

Eg. https://m.youtube.com/watch?v=ZwuVpNYrKPY

Not to mention plants (oxygen is a waste product for them), some fungi, etc. They're multicellular, but not animals.

A plant’s metabolism still needs to function even when the sun isn’t shining.

So they consume oxygen at night, in their roots, etc. This is most apparent for the occasional parasitic plant without chlorophyll. https://en.wikipedia.org/wiki/Albino_redwood

Plants still perform respiration using oxygen. Photosynthesis lets them create their own sugars, but their process for using those sugars in the mitochondria is similar to how we do it. Plants release more oxygen than they consume because they grow: in order to grow they must pull CO2 from the air, use the C as building material (instead of respiration fuel), and dump the O2.

https://www.pthorticulture.com/en-us/training-center/basics-...

An interesting thing about these is that they may have started as cancer cells that escaped their original host jellyfish.

Wow, I never knew that could happen! Are there other examples or a name for this phenomenon?

Good scifi. We need Egan or Hughes to do it up. It's like Battlestar Galactica, except with cellular stuff.

Maybe a cheery tale from Peter Watts?

There are contagious cancers that you can catch via blood transfer. This has wiped out most of Australia's Tasmanian Devil population.

That's surprising. Why doesn't the HLA system work in this case ?

Genetic bottleneck, they don't have enough genetic diversity to recognize the cancer cells as foreign.

By most, parent means 80% species die-off rates. :(

Disclaimer: sad pictures of extreme facial tumors

https://en.m.wikipedia.org/wiki/Devil_facial_tumour_disease

The article says that there is a gene for resistance to that cancer already present in the Tasmanian Devil genome. It's a fascinating mechanism. Wonder if it evolved related to overpopulation?

The likely reason the cancer is transmittable at all is due to underpopulation/genetic bottleneck. Animal immune systems usually have no problem recognizing and destroying cells from other individuals, even cancerous ones, but you need sufficiently distinct immune markers on your cells for them to recognize as "foreign."

Immortal sexually transmitted canine cancer.

Ha! Plucky little tumors.

The cnidarians are a really interesting part of the animal kingdom. They “break all three rules”, like having single-celled animals, animals that are supposedly “immortal” if nothing kills them (certain jellyfish), and now this.

I could see one of them becoming the next humans if we wipe ourselves out.

I generally root for cephalopoda in this regard.

As noted in the article, the discovery is from 2020: https://english.tau.ac.il/news/no_oxygen

Funny that this article from 21 June 2024 is the one finally gaining traction.

They look like someone asked an AI to draw “Alien Sperm”

It is amazing how different evolution trees converge on optimal configurations. It reminds me of crabs.

ironic, because crabs remind me of bad choices made when drunk involving aliens

Most people don’t know that there are species that can, e.g. drop their metabolic rate down to .01% of baseline to survive without water or food for 30 yrs. Or survive in high radiation environments, or high pressure and temperature environments. More people should know that there is genetic precedent for crazy phenotypes that could theoretically extend to other species in the future.

https://en.m.wikipedia.org/wiki/Tardigrade

Tuberculosis has an alternative metabolism that allows it to survive even encased in an oxygen -free environment that the immune system puts around it, called granulomas. There are 2000y old mummies with granulomas in their lungs that were found to still contain live tuberculosis.

Are you certain about the 2000 year dating?

I curious because the mummification process changed drastically over time, and during the early Roman period was much less elaborate than 1000 years earlier.

Original paper (2020):

https://www.pnas.org/doi/10.1073/pnas.1909907117

One thing not mentioned, will these die quickly if not attached to its host ?

I did a quick search but without luck.

These look like lil tiny Meeseeks

> The research was published in PNAS

Between this and the images I realize that I can still be mentally 12 at times.

By ditching the need for oxygen I wonder what these critters use for energy? I'd imagine their parasitism is related...

"no one wants to buy salmon riddled with tiny weird jellyfish"

A really interesting article, but I'm not sure if that statement above is really universaly true.

In Japan they'd probably make sushi out of them... 8-)

>"In 2020, scientists discovered a jellyfish-like parasite [common salmon parasite called Henneguya salminicola] that doesn't have a mitochondrial genome – the first multicellular organism ever found with such an absence. That means it doesn't breathe; in fact, it lives its life completely free of oxygen dependency. [...] It's a cnidarian, belonging to the same phylum as corals, jellyfish, and anemones. Although the cysts it creates in the fish's flesh are unsightly, the parasites are not harmful, and will live with the salmon for its entire life cycle. Tucked away inside its host, the tiny cnidarian can survive quite hypoxic [oxygen deficient] conditions."

This sounds like a very interesting candidate organism to bring to Mars in the future...

Um, are my eyes deceiving me, or did I read e.g.

* "Multicellular life needs oxygen to live." * "They break down oxygen to produce a molecule called adenosine triphosphate..."

That's explaining what normally happens -what the subject differs from

Looks like I've been ninja'ed.

That paragraph is referring to mitochondria, which the scientists discovered are not present in the subject of the article.

Human ego at its finest. If we can’t do it, nobody in the universe can. I’m loving the humbling

Why do we keep acting like we know what the requirements for life are? Those we look to for insight on this are most entrenched in socially accepted fallacies - oxygen is required, carbon is required, water is required.. and based on what evidence? We have a sample size of one - Earth. It's laughable that we're therefore so committed to defining requirements for life.

We don't really understand the mechanism that spawns life, so we can't say we understand its requirements.

It's implied that what's being discussed by requirements is for life "as we know it".

Implication is not explicit and therefore subject to each reader's interpretation. i.e. what seems to be implied to one's perspective may not actually be implied from all's perspective.

This kind of thing is implied in most science communication, every statement of fact has a "unless or until conflicting information is found" tied to it by common sense.

We also know of the Great Oxidation Event [1], and that life on earth is older than that.

Animals are recent-ish (~500mya) but single cell organisms that do not require oxygen must exist.

[1] https://en.wikipedia.org/wiki/Great_Oxidation_Event

Anaerobic microorganisms do exist, but the article is talking about animals.

Well, we've got some pretty good hypothesis about the mechanisms that spawn life, and we can extrapolate from there a little - though I do understand your point that we are burdened with an embarrassingly small sample size.

For instance, the alkaline thermal vent origin hypothesis stands up to scrutiny - it may well end up being wrong, but the other contenders are not so robust.

We know carbon is probably key, because of its properties, notably abundance and ability to oxidise (as Nick Lane, I think it was, quipped something like 'try growing a body with sand' (ie. silicon based lifeform)).

I think the surprise here is the assumptions made around multi-cellular / mitochondria / krebbs (ATP) were so consistently observed, that an exception really stands out.

Your tone suggests we shouldn't speculate about what requirements life has - but I don't think the intent is as full of malice as you appear to believe. I take it more as a curiosity meets a (prinerdial) need to catalogue everything, and then getting frustrated when things aren't so easily pidgeon-holed.

Because it enables journalists to make their articles more interesting.

Lee Cronin is working on Assembly theory, which should enable measuring complexity in substances, with high complexity implying some life there. His interviews with Lex Friedman are pretty good.

>Why do we keep acting like we know what the requirements for life are?

Because of our empirical experience and study of hundreds of thousands of organisms from all kinds of species.

>We have a sample size of one - Earth. It's laughable that we're therefore so committed to defining requirements for life.

We also have sample sizes of many other nearby planets and astral bodies with no signs of life.

We also have samples of other nearby planets and astral bodies that do have signs of life. Signs, not evidence.

Mars, Enceladus, Titan, Europa, and some other places have signs that life might be present. Might be. Don't bet on any of them, but there is still a lot to be explored.

We didn’t think oxygen was required for life. We knew about plants.

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