I just finished reading After the Dinosaurs. It wasn't a bad read whatsoever. Often it was quite engaging. The writer, Donald Prothero, definitely has some nontrivial skills in producing some prose that is not dessicated to mummification and gives a pretty good overview of the last 65 million years of climatic and mammalian evolution (with tidbits of reptiles and birds). Not being a mammalian specialist - in truth paleo stuff is a hobby, not a profession, so I couldn't be a specialist in anything really - I have been taking everything he said with a grain of salt: not because he's necessarily wrong, but as a precaution as I slowly creep towards understanding the Cenozoic as a whole in both climate and biological aspects. Either way though there were some surprising aspects to Prothero's book.
One of the things that came across was the pure vehemence that Dr Prothero has wrt the possibility that impacts could cause extinctions. He spends a considerable number of pages discussing the KT Extinction and why he feels that it could not be caused by an impact. Furthermore, later on he spends a nontrivial amount of wordage showing that the Eocene extinctions were not caused by the numerous recorded impacts there [I haven't read much on the Eocene extinctions as yet, so I will withhold commentary there]. The vehemence was striking though. At one point he was arguing that the the impactists were 'twisting' evidence to suit them!
There is a long and nasty history of mud slinging wrt mas extinction studies especially between those for and against the KT Impact Extinction Theory. The most famous of that being Dr Luis Alvarez's public slamming of vertebrate paleontologists in the New York Times as 'stamp collectors.' This hasn't let up as far as I can tell especially between Drs Smitt and Keller. oy. At some point I am going to do a post on the subject, but not quite yet.
One of the interesting and odd bits that came out of the book was on human evolution (keeping with Bryan's request that we put in something for the Pleistocene for the next Boneyard). The interesting and odd bit was that Prothero suggested that due to some recent work that Homo erectus survived up until 27k years ago well within the Pleistocene and damned near being Holocene in its age: even outsurviving the Neandertals! The reference is to book by a sometimes collaborator, CC Swisher. This predates the whole excitement over Homo floresiensis and in the same neighborhood, no less! Makes you wonder just how provincial that area was hominid wise. Then again the peoples that swept down into Australia had already been through, so how H erectus could have hung on since it shares a niche with plain, ole, nasty us would be challenging.
Another interesting bit was that about the evolution, migration, and extinction of the primates in North America. It seems that Plesiadapiformes were not only common, but along with the Multituberculates made up the arboreal mammalian fauna: what we would now think of as squirrels. They were quite common and really diverse. In fact, the mammals of North America were pretty endemic at this point. Then came during the Eocene, something of another invasion with the Adapids and Omomyids invading from either Europe or Asia depending on what the new discoveries actually reveal. This drove the locals extinct by the end of the Eocene and ironically the new invaders would end up extinct as well. I have Prothero's other book on the Eocene-Oligocene transition and I'll be reading that in the near future as well, but after a another round of political and technical books.
The last discussion that really caught my interest, of course, dealt with the so-called overkill hypothesis or the 6th mass extinction. In discussing it, Prothero has some good points. However, his arguing style isn't terribly persuasive largely because there are inconvenient things that he glosses over wrt the human caused extinctions. OTOH, he does point out that it is very likely that humans had a nontrivial contribution to the extinction: after all islands around the world have been devastated by aboriginal peoples around the world and today all societies are having a serious impact on the environment. However, the radically changing environment, he argues, had to play a role too.
Something that we all should keep in mind is that our world as we see it and know it, even without the impacts mankind has had is truly young: the Amazon didn't cover its whole territory during the Pleistocene, in fact, it was only extent in small, small patches. It may not have even been close to its current size until much less than 10k years ago. That is something that is rather sobering! It brings up the question then of whether or not the vast diversity we see in the Amazon is the result of it being a tropical rain forest, or is it because we are seeing the slamming together and unification of multiple isolated populations from scattered forests that grew together. Are we actually observing stable ecologies there? Or are we observing a chaotic situation that we wouldn't even notice had we been looking at this in the form of fossils some x million years hence. I don't have any answers to this, but based on what I took away from reading Pielou's work some time ago is that we are not in a period of ecological stability even without mankind's environmental damage.
My own position so far and with only some reading on the subject is that humanity is probably the primary suspect in the extinction of the megafauna, but not the only one. I strongly agree with what Dr Hallam stated in one of the books I reviewed almost two years ago:
amen.
That said, I don't think its impossible in the future though. Optimist I am. ;)
At any rate, I am out of time for today. I just wanted to share a few thoughts and reactions to the latest paleo book I read. Please feel free to comment on them. :)
1. Odd tree that one. Kenyapithecus had two species. One being K. rudolfensis? This is from the Leakey's, right? Also what is Homo cepranensis?
One of the things that came across was the pure vehemence that Dr Prothero has wrt the possibility that impacts could cause extinctions. He spends a considerable number of pages discussing the KT Extinction and why he feels that it could not be caused by an impact. Furthermore, later on he spends a nontrivial amount of wordage showing that the Eocene extinctions were not caused by the numerous recorded impacts there [I haven't read much on the Eocene extinctions as yet, so I will withhold commentary there]. The vehemence was striking though. At one point he was arguing that the the impactists were 'twisting' evidence to suit them!
There is a long and nasty history of mud slinging wrt mas extinction studies especially between those for and against the KT Impact Extinction Theory. The most famous of that being Dr Luis Alvarez's public slamming of vertebrate paleontologists in the New York Times as 'stamp collectors.' This hasn't let up as far as I can tell especially between Drs Smitt and Keller. oy. At some point I am going to do a post on the subject, but not quite yet.
One of the interesting and odd bits that came out of the book was on human evolution (keeping with Bryan's request that we put in something for the Pleistocene for the next Boneyard). The interesting and odd bit was that Prothero suggested that due to some recent work that Homo erectus survived up until 27k years ago well within the Pleistocene and damned near being Holocene in its age: even outsurviving the Neandertals! The reference is to book by a sometimes collaborator, CC Swisher. This predates the whole excitement over Homo floresiensis and in the same neighborhood, no less! Makes you wonder just how provincial that area was hominid wise. Then again the peoples that swept down into Australia had already been through, so how H erectus could have hung on since it shares a niche with plain, ole, nasty us would be challenging.
Another interesting bit was that about the evolution, migration, and extinction of the primates in North America. It seems that Plesiadapiformes were not only common, but along with the Multituberculates made up the arboreal mammalian fauna: what we would now think of as squirrels. They were quite common and really diverse. In fact, the mammals of North America were pretty endemic at this point. Then came during the Eocene, something of another invasion with the Adapids and Omomyids invading from either Europe or Asia depending on what the new discoveries actually reveal. This drove the locals extinct by the end of the Eocene and ironically the new invaders would end up extinct as well. I have Prothero's other book on the Eocene-Oligocene transition and I'll be reading that in the near future as well, but after a another round of political and technical books.
The last discussion that really caught my interest, of course, dealt with the so-called overkill hypothesis or the 6th mass extinction. In discussing it, Prothero has some good points. However, his arguing style isn't terribly persuasive largely because there are inconvenient things that he glosses over wrt the human caused extinctions. OTOH, he does point out that it is very likely that humans had a nontrivial contribution to the extinction: after all islands around the world have been devastated by aboriginal peoples around the world and today all societies are having a serious impact on the environment. However, the radically changing environment, he argues, had to play a role too.
Something that we all should keep in mind is that our world as we see it and know it, even without the impacts mankind has had is truly young: the Amazon didn't cover its whole territory during the Pleistocene, in fact, it was only extent in small, small patches. It may not have even been close to its current size until much less than 10k years ago. That is something that is rather sobering! It brings up the question then of whether or not the vast diversity we see in the Amazon is the result of it being a tropical rain forest, or is it because we are seeing the slamming together and unification of multiple isolated populations from scattered forests that grew together. Are we actually observing stable ecologies there? Or are we observing a chaotic situation that we wouldn't even notice had we been looking at this in the form of fossils some x million years hence. I don't have any answers to this, but based on what I took away from reading Pielou's work some time ago is that we are not in a period of ecological stability even without mankind's environmental damage.
My own position so far and with only some reading on the subject is that humanity is probably the primary suspect in the extinction of the megafauna, but not the only one. I strongly agree with what Dr Hallam stated in one of the books I reviewed almost two years ago:
The sombre picture outlined above should dispel once and for all the romantic idea of the superior ecological wisdom of nonWestern and pre-colonial societies. The notion of the noble savage living in harmony with Nature should be despatched to the realm of mythology where it belongs. Human beings have never lived in harmony with nature.
amen.
That said, I don't think its impossible in the future though. Optimist I am. ;)
At any rate, I am out of time for today. I just wanted to share a few thoughts and reactions to the latest paleo book I read. Please feel free to comment on them. :)
1. Odd tree that one. Kenyapithecus had two species. One being K. rudolfensis? This is from the Leakey's, right? Also what is Homo cepranensis?
4 comments:
Okay, see? I'm glad I didn't buy this book. I thought it was an edited volume, like "Horns & Beaks" or "Thunder Lizards."
I was hoping for something more specific to the Paleocene and Eocene only. In that respect I was rather disappointed. The Paleocene was only very lightly touched on compared to the Oligocene-Eocene boundary.
Yeah, the tropical rain forest diversity thing is a puzzler. There have been some attempts to derive it from energetics and ecological first principles, none really successful. It's probably fairer to say that, if a bunch of different tropical rain forest ecologies glom together, no one ecology can dominate the rest.
Energetics would explain some of the diversity, but not enough.
TRF diversity - to me, the not specialist - really does look like multiple ecosystems slammed together after a million or so years of isolation. None was inheritly "fitter" than the others, so its a free for all. It really makes sense with the bits I have found out wrt the Amazon rain forest's Pleistocene range.
Apparently though its a really, really contentious issue with researchers. :)
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