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