As I mentioned earlier, I am fascinated at how life “terraforms” a planet. But it does it in waves, in fits-n-starts, sometimes the bio-products exceed tipping points, things crash, then build again. Evolving life can destroy itself then pick up again, both altered by and altering its environment.

We take turns.

Precision and accuracy in intellectual matters is a laudable goal. For my own part, I respect academic rigor, I do not see it, as has lately become fashionable in our country, as treasonous, seditious, conceited and effeminate.

My whole point is that I am starting to see the rise of multicellular organisms as possibly being an inevitable step in the evolution of life, not just a happy accident in our lonely little corner of the cosmos. The consequences for CETI are profound.

https://www.sciencedaily.com/releases/2020/05/200507130704.htm

Also, hank, I can see why including the Edicarian in a term like “Precambrian Explosion” is sort of technically correct. It bothers me though. Is it because I learned it as Cambrian Explosion, or that I don’t think the life in the Edicarian was as big an acceleration as the Cambrian, or that maybe the boundary for the Phanerozoic/Precambrian should be moved to reflect our growing knowledge, otherwise Neoproterozic Explosion is too much of a mouthful? Not sure. But I do know I was being pedantic. Sorry ’bout that.

https://boingboing.net/2020/04/16/giant-string-like-creature-com.html

Hate to take out the red pen on you hank, but as a teacher with no class: it’s the Cambrian Explosion.

Stromatolites were more microbial mats (mostly cyanobacteria) than anything as organized as a sponge. But both filter feeders, sooo…

Been reading some new research on Snowball Earth (cnn -long story here*, I know this outcrop and one of the authors) and I personally think that this is what kept multicellular life from exploding far earlier in earth’s history. But it could have been the terraforming of the atmosphere done by early lifeforms that could have caused the freezing feedback loop.

But yes, I do think there is this slow but sure way of creating multicellular life and higher life forms by increasing the cooperation of individuals. (competition too, but it’s a balance.) I was fascinated by an idea I heard years ago about how the first cells formed. The question was how did these proteins and amino acids manage to create a sphere to contain themselves. The hypothesis was they started out in two dimensions, not three, organizing between the cleavages (crystallographic layers) of clay minerals. They didn’t need to create a whole sphere, just a fence. Eventually, these fences shrunk in area until the surface tension led to creating spheres.

Finally, I’m not real convinced by the tiny leaf fossil shown at the link. I’d have to see the cited paper or others describing these rocks.

The final sentence of the abstract is always the big take-away. Even a billion years a hell of a long time ago on a tectonically active planet.

Thanks for the link.

* I wrote a big long post about this article, how it doesn’t really get into what the scientific paper is about, but lost it to a bad keystroke. ARRRRgggg