Thursday, July 12, 2007

Why the Permian Extinction Matters

I am long overdue on posting something substantial in the paleo realm. Today I am working on doing an upgrade and server flip of our centerwide file system. As this progresses I am going to try to bang out my long promised post while I keep an eye on the progress of the upgrade and server switch. We'll see how this works.

The Permian Extinction has been called 'The Great Dying'. It has also been called 'When Life Nearly Died'. his is the extinction that wiped out vast quantities of life. The highest numbers given are often in the 90th percentile, but almost never lower than the 70th. There were vast amounts of critters and green stuff that just ceased to continue through the long, dark voyage over the chronological seas of Deep Time to the present day. I have a post up earlier about the Great Dying as to the mechanics of said meltdown. I suggest that you look there for a lot of the details in that respect. What I'd like to discuss in this post are some of the consequences of the Mass Southern Fried Splat (or Therapsid Chips with Salty Sulfide Vinegar for our Brit readers).

The consequences of the Permian Mass Extinction are very profound. They are not simply this creature replaced that. Nor are they that there were some uppity usurpers that took advantage took advantage of the reigning lineages' collective ill health. It's not as mind numbingly simple as that. Life tends to find some very odd ball ways of changing what it does. Mass extinctions are something of a rules reset. In some ways this seems obvious: a vast number of players in the previous game are gone. The remaining players are going to relate to each other differently and there is definitely room for new players. These new players are not the same as the replaced ones; therefore, the way the remaining old timers and the newbies relate will be different. This offers some a chance for further openings at the table for still more players. Peter Ward remarked in his book Rivers in Time that it seems like life through Deep Time fits a level of ecological complexity and stays there. Then a mass extinction happens and the level of complexity drops radically only to rebound with far more vigor reaching up to greater heights. There was a more recent paper that had some data in support of this from this past November wrt marine ecosystems and the Permian Extinction.

(credit: Dr Benton's book.)

There are some arguments against this. namely that prior to the end of the Permian, prior to the double mass extinction, complexity was arising on land, at least, as the vertebrates took to herbivory and detrivory fell by the way side. The argument goes along the lines that the complexity was arising already and would have come about anyways. The mass extinction just altered the players instead of the game. However, it is looking like the other side of this argument is gaining more and more strength. Time and science will tell.

Another consequence is often spoken of metaphorically, but that metaphor taken far too seriously. As a consequence of the Permian Mass Extinction, the therapsid dominated ecology fell apart, a lot of different reptilian vertebrates, especially the diapsids, would take advantage of the situation. The dinosaurs, as a consequence, eventually arose from those diapsid experiments. As a consequence, our ancestors, the cynodonts, would be marginalized from the megafauna roles. Some people come out and refer to this as the diapsid 'usurpers' 'dethroning' the 'rightful heirs' - the synapsids - from their rightful roles. Another group has come out and said that if not for the dinosaurs, our acnestors would have been on the moon 185 million years ago! There's a humorous cartoon with a mammal pondering how to get there with a dinosaur about to eat it, but I have been unable to find it online. Either way, this is complete and utter buffalo chips.

First off there's no such thing as a rightful ruler or whatnot in the environment. That is just plain silly to even think of it that way. The second is that the whole series of events that led to humanity being evolved would have been completely and utterly negated just based on the knock-on and butterfly effects that were so different from Our Time Line (OTL). With no Permian Extinction, with no dinosaurs, there would be no Humanity. For one the environment would have been radically different. 185 million years ago is rather different from now. Second, the therapsids would have continued on and that means our little furry ancestors may or may not have even developed. There's no saying since the pool of therapsids that made it through the PTE was rather limited compared to what came before. it would not have been a Sooner Age of Mammals. It would have been the Age of Therpsida which our furry forerunners may - or may not - have been a part of. Placentals may or may not have evolved. Marsupials may or may not have evolved. everything is too contingent. Humanity is probably right out in the faerie tales then.

(Credit: Alex Freeman).

The PTE, and the subsequent KT Event, both had a very profound impact that isn't one about whether or not we are here. Rather it's one of perception. Let's argue for a moment that we had a bunch of nonmammalian therapsids survive to modern times. For this experiment, they would need to be somewhere that they would not effect human evolution, yet would be present for modern civilization to have to contemplate. The perfect place would be South America. When the Panama Isthmus connects up, they spread up through NorAm and then into Eurasia. With luck, they make it to modern times. Now, if the nonmammalian therapsids are about then how we perceive the world and the differences between animals will be different. Right now, it's very "obvious" what the difference is between a mammal and a reptile, right? If there are nonfuzzy, nonmammalian therapsids running around that line would appear blurrier, right?

Now if there were some that had fur as well...would the theory of evolution have arisen sooner? Would we have viewed the world quite a bit differently if not for the extinctions "robbing" us of living intermediate stages? Or would we in our benighted state still come up with goof ball reasons for these 'tweeners? Well, probably, honestly, but might not our perception of the world have been rather, well, different? I'd say so. If we were here to see. If they were here to be seen.

There is one last reason as well that I think I am going to write about. The mechanism of how the world got roasted, as I noted above, is one of a run away greenhouse effect. A 10 C spike in temperatures was what roasted the world and caused all those mass extinctions. If humanity, in its infinite stupidity, decides that it wants to let things get that ought of hand with global warming, then we could see another stab at life nearly getting wiped. The projected heat increases are far, far less than the Permian for the next century, even in the worst case scenario, but we do need to take responsibility for our actions and halt the use of fossil fuels before we get to the Permian Steak House stage.

There are other reasons as well, but I am going to leave them in their fossiliferous state. I am out of time for today and don't want this post to languish in my drafts section like the ones about Mexico. And politics. And the future biotic timeline. And more paleo stuff. and...oy. For now, enjoy!

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