Scientists Find The First Animal That Doesn't Need Oxygen to Survive

[Judi Lynn]

MICHELLE STARR 10 MAY 2020

Some truths about the Universe and our experience in it seem immutable. The sky is up. Gravity sucks. Nothing can travel faster than light. Multicellular life needs oxygen to live. Except we might need to rethink that last one.

Earlier this year, scientists discovered that a jellyfish-like parasite doesn't have a mitochondrial genome - the first multicellular organism known to have this absence. That means it doesn't breathe; in fact, it lives its life completely free of oxygen dependency.

This discovery isn't just changing our understanding of how life can work here on Earth - it could also have implications for the search for extraterrestrial life.

Life started to develop the ability to metabolise oxygen - that is, respirate - sometime over 1.45 billion years ago. A larger archaeon engulfed a smaller bacterium, and somehow the bacterium's new home was beneficial to both parties, and the two stayed together.

More:
https://www.sciencealert.com/scientists-find-the-first-animal-that-doesn-t-need-oxygen-to-survive

[Bayard]

1. Looks kind of like the Bat Signal

I like that bit about, "extraterrestrial life.".

[AJT]

2. There are multicellular organisms without mitochondrial DNA

deep in the ocean. I don't understand how this can be the first.

[Buckeye_Democrat]

3. It surprises me too.

I didn't major in the life sciences, so there's a LOT that I don't know about it (beyond the basics)

Here's an example of a (non-complex) eukaryote cell that made the news in 2016:
https://phys.org/news/2016-05-eukaryote-lacks-mitochondria.html

Mitochondria are membrane-bound components within cells that are often described as the cells' powerhouses. They've long been considered as essential components for life in eukaryotes, the group including plants, fungi, animals, and unicellular protists, if for no other reason than that every known eukaryote had them. But researchers reporting in the Cell Press journal Current Biology on May 12, 2016 now challenge this notion. They've discovered a eukaryote that contains absolutely no trace of mitochondria at all.

Side-note: My own mitochondria, inherited from my mother and her distant female lineage, is supposedly among the least efficient (and heat-producing), making me a bad candidate for stuff like long-distance running, but great in very cold weather. (Which is indeed true, from my past comparisons to others around me -- e.g., my father often had to "bundle up" while the rest of us in the house were "burning up".)

[muriel_volestrangler]

4. It seems there is some dispute whether those loriciferans are truly anaerobic

See http://www.bbc.com/earth/story/20170125-there-is-one-animal-that-seems-to-survive-without-oxygen

The team found the same species of loriciferans discovered by Danovaro. But these loriciferans were living in environments with normal levels of oxygen, and in the upper layers of the sediment above the anoxic pools, which had low levels of oxygen.

The closer the researchers' samples came to the anoxic basin of water, the fewer living loriciferans they found.

Bernhard argues that it is extremely unlikely that loriciferans would be adapted to live both in areas totally without oxygen and high in salt, and also in environments with plentiful oxygen and normal levels of salt.
...
However, in June 2016 Danovaro and his team came back fighting against this alternative scenario. They say that, because Bernhard's team did not collect mud samples from the areas of the basin that are permanently without oxygen, they cannot be sure that loriciferans do not live there.

http://www.bbc.com/earth/story/20170125-there-is-one-animal-that-seems-to-survive-without-oxygen