Even the worst mass extinction had its oases

* End-Permian is associated with the Siberian Traps, but those in turn are associated with the Wilkes Land Crater impactor, which is antipodal to that event and may have seen antipodal seismic focusing.

* "Going on for thousands of years" - Dating the End-Permian has confidence intervals on the order of 30,000 years.

* Small size and diverse ecology almost guarantees survival of life. There is life basically everywhere we look, down to extremophiles living very slow lives in a random cubic meter of "solid rock" two kilometers deep. We have even evolved several chemical alternatives to photosynthesis as a primary energy source. Mammals and small birds deep in a cave somewhere appear to have been some of the only land vertebrates to survive K-T, and radiated out from there. Evolution does the rest.

  > End-Permian seems tied to the Siberian Traps basaltic eruption,
  > but that eruption had been going for thousands of years before
  > the dieoff started.

Biologists like to proclaim that things are gradual when they're really more likely sudden. This often reflects mathematical ignorance. For example, if the last specimin of a certain rare fossil is found in a stratum slightly older than the K-T stratum, does that mean it went extinct earlier than the K-T event? Probably not; it just means the fossil is rare so your sampling error is larger.

Thanks for adding to this.

Not an expert on this by any means, but I always found this short series [1] quite fascinating on how cyanobacteria over a period of 200-300 million years coverted the planet from being methane based to being oxygen based, created the ozone layer and paved the way for photosynthesis, oxygen and life as we know it. I can't remember if I'm being too optimistic when I'm recalling bacteria doing something similar for the mass extinctions?

See also [2]

[1] https://www.bbc.co.uk/programmes/p09xj73n

[2] https://asm.org/Articles/2022/February/The-Great-Oxidation-E...

>but end-Permian seemed to be a "first gradually, then suddenly" as pollution from the traps put more and more stress on the biosphere until suddenly...

AKA the Seneca effect. See https://terebess.hu/keletkultinfo/seneca.pdf

> He thought that there is a big gap in our knowledge of survival and recovery.

Well, you don't want to know how far you can safely bend over the cliff before falling down. I think attempts to gain such knowledge in a practical way should be explicitly banned.

Thanks for the great summary!

Some total niche bacteria doing millenias of groundwork.

I wonder if the P-T extinction was due not just to CO2 release from the volcanism (and the other bad effects from the magma intruding into the largest/oldest sedimentary basin in the world), but also due to authigenic clay formation in the ocean.

When clay forms in the ocean, it pulls calcium out of seawater. Calcium is normally balanced by two bicarbonate ions, so its removal causes the bicarbonate to shift back to carbonic acid/CO2. The ocean acidifies and CO2 is released. This has been called "anti-weathering", since it's the opposite of the normal process that draws down CO2 by weathering of silicates.

Sufficient injection of silicic acid and aluminum into the ocean could accelerate this process.

Scientists are aware and account for that.

One way they do that is by focusing not on megafauna but on creatures that exist in immense numbers in a biosphere like insects or even smaller creatures. They also look at pollen and other biological matter that gets spread evenly.

They can also look at the effects life has on the structure and chemistry of earth. For instance, they know when oxygenation happened because there are chemicals in older rocks that can not form in the presence of oxygen, while there are chemicals in younger rocks that can only form in the presence of oxygen.

A big evidence that the end-Permian effected land as much as the ocean is the behavior of rivers. When plants are present, rivers tend to meander because plant roots hold onto the river banks. When plants are not present, the river is able to take the shortest path to the ocean. Rivers banks laid down at the end of the Permian meander, river banks laid down at the start of the Triassic do not.

This is why "evolution" is just another creation myth. Of the 0.01% evidence left in the fossil record, massive leaps of faith are needed to construct a definite story with any certainty. Darwin wrote about this as well.

The artist appears to be committed to the bit:

https://fineartamerica.com/profiles/corey-ford?tab=artwork

It does stand to reason that if there was life on Mars there might still be life on Mars. Everywhere we look on Earth, life exists, even in extreme environments and independent of the sun's energy.

I think the first alien we'll find will be an extremophile bacteria or other microorganism.

Latin "Terra" actually meant "dry", so it was the proper term for dry lands, as opposed to seas and oceans. For instance, "continent" is an abbreviation for "terra continens", i.e. dry land that is contiguous. Spanish "tierra" and the cognate words in the other Romance languages, which usually correspond to English "land", have remained closer to the original meaning of the word.

The entire planet was very seldom, if ever, referred as "Terra". The correct Latin word for the entire planet was "Tellus" (whence the adjective "telluric"), whose likely meaning was "support" in the sense "the earth that supports us on it".

Using "terrestrial" to refer only to land-based life is proper, i.e., it's a common and accepted definition of the word.