In Kentucky, there's a museum with a lifesize model of a dinosaur with a saddle on it. This is a hymn in fiberglass to young Earth creationism, the idea that the Universe was created about 6,000 years ago.
It costs $1,500 to become a charter member (family rate) of this museum. A much better investment would be $24.95 for Douglas Erwin's thriller about the Permian extinction.
More than nine-tenths of all species died out 251 million years ago. Erwin, a researcher with the Smithsonian Institution's National Museum of Natural History and the Santa Fe Institute, finds the end-Permian "enigma far more compelling than the end of the dinosaurs," a relatively minor event from 65 million years ago.
For an event that Kentuckians think never happened, the end-Permian event left a lot of debris, of which the most interesting is in China. Until 20 years ago, the paleontological record there was unknown to the outside world.
What the evidence is telling us is difficult to say. Erwin says "Extinction" was "frankly written as a mystery story." In this one, the clever detective does not wrap up all the loose ends on the last page.
Instead, we learn that there are at least seven major theories of what might have happened. These range from a big meteorite to gigantic volcanic eruptions in Siberia to a climatic or biological or geological change that drove oxygen out of the oceans.
The first chapters set the stage. Life was very different in the Permian. There were reefs in warm oceans, and they contained corals, but the corals were only distantly related to those of today and they were not as important as crinoids and lampshells, animals that still exist in out-of-the-way places.
On land, flowering plants had not yet evolved, nor mammals, dinosaurs or saddles. In South Africa's Karoo basin, fossils remain of a fabulous, lost fauna.
There were widespread extinctions on land as well as in the sea during the end-Permian event, but it is hard to say whether the land extinction was as complete as in the sea, where 94 percent of species disappeared in a short time. Erwin's team and their Chinese collaborators have found evidence that it all happened in less than 160,000 years -- maybe a lot less.
It is also not proved that the big land extinction exactly coincided with the sea kill, but it seems likely. The land kill was a whopper, too. This was apparently the only time in history when a mass extinction had any real impact on insects.
Whatever the cause, it did set up the modern world. "Mass extinction is a powerful creative force," says Erwin.
Or did it? As they learn more and more of the details, scientists are also learning to question the easy assumptions of more innocent decades.
Evolutionary biologists are vigorously debating whether the animals and plants that dominated the Permian were already being outcompeted by the early forerunners of modern flora and fauna, or whether they would have maintained their control of resources.
Erwin, splendidly agnostic about this and other debates, lays out the questions but leaves the resolution for some other time. Perhaps not too far in the future. He notes that his 1993 book on the Permian extinction already is out of date in many ways.
In fact, after decades researching the extinction itself, he has now concluded that "understanding the recovery from the extinction poses a far greater intellectual challenge."
Any scientist who opens [and closes!] a book by saying "We [I] don't know!" is worthy of your attention and respect. Too many others have taken up a theme and defended against all comers. Erwin's examination of the catastrophic close of the Permian Age is complete, admirably researched and exquisitely written. Within its pages, this work examines the various ideas on the massive loss of life 250 million years ago. These days, not to have heard of an meteor's killing off the dinosaurs 65 million years ago suggests you've lived hidden in a cave for a generation. Erwin opens with a brief overview of that event, reminding us that extinctions, particularly "impact events", have loomed large in discussions of the history of life ever since Walter and Luis Alvarez proposed the idea.
It's easy to rattle off the numbers: when the dinosaurs "went West", perhaps 75% of life was also extinguished. When the Permian ended, over 95% of living things disappeared. Erwin asks: "How do we know this? What life forms disappeared? Did they all go at the same time? How long did it take to recover?" Most important, of course, "What killed them off?" Instead of dull statistics, Erwin asks the important questions. Acknowledging that "Triassic rocks are boring", he explains why this is so. Fossils are scarce is the obvious answer, but why they are missing is his quest. With most of his attention focussed on ocean life, he details what causes shifts in benthic populations. The seas rise and fall - for a variety of reasons. Glaciation takes up sea water and leaves continental shelves high and dry. Oceans need to "turn over" an oxygen supply. What is the result of that failing? Carbon, with its various isotopes, passes through life selectively. Tracing that path provides insights into where it's been - and where not. When did the Siberian "traps" form? How much lava spewed from that rift, and what other products did it bring along or destroy? Finally, is there evidence that Earth was pelted by another bolide to provide an easy answer to all those questions? That reply is almost surely negative.
Erwin would like to couch this narrative as a detective story, but it doesn't really work. There are too many victims - unless you count life as one entity. There is also a phalanx of detectives all trying assiduously to solve the case. If you thought there were too many cooks spoiling the broth, wait until you meet this mob. Nearly all of them have an agenda and they have a disturbing tendency to trumpet a single tune. Erwin should have portrayed them as an orchestra, with himself as conductor. Van Kariajan would go emerald with envy. Each investigator supplies a theme, striving for a solo performance. Erwin cautiously assesses the tune, fits it nicely into a grander theme and produces a symphony instead of a cacophony. It's quite a performance. To keep himself from the sin of hubris, he points out his own flaws in a previous effort. The strain wasn't discordant, but the composition needed refinement.
Erwin fastidiously acknowledges his contributors. Jack Sepkowski comes in for deserved accolades, as do Bruce Rubridge, Yugan Jin and many others. Their methods, results and further work - including that incomplete but "promised" - are given a full hearing. Even those whose suggestions are highly suspicious, such as Luann Becker's Bedout "crater" are given a respectful hearing. Nobody's work is chastised or rejected. "We need more investigation" is the running theme of Erwin's account. The reason the ongoing search is important lies in understanding what is happening around us today. Are we, in Dave Sepkowski's words a "Dead Clade Walking"? Or can we glean enough information from the rocks to find the means to succeed through the extinction we seem to be part of - and likely creating? The "95%" means life had to restart the clock after the Permian. There were a few "Lazarus species" that re-emerged after the cataclysm. Will the human species manage to revive itself when so much life around us has been decimated? No more pertinent question confronts us. [stephen a. haines - Ottawa, Canada]
Even kids now can tell you about the mass extinction that wiped out the dinosaurs. When I was a kid, the dinosaur extinction was a big mystery, but there has been good evidence, now broadly accepted, that 65 million years ago a meteor as big as a mountain smashed into the Yucatan, turning everything for miles around into ash, wrapping the world in a cloud, and blocking the sunlight that runs all life. Everything all over the world changed, and we mammals got our try at reproductive success. The horrendous extinction that ended the Cretaceous age, however, wasn't the worst our old Earth had seen. 250 million years ago, there was an extinction that ended the Permian and began the Triassic periods (which is also the border between the larger, more general Paleozoic and Mesozoic eras). This Permo-Triassic event extinguished around 95 percent of all living species, and was as close as we have ever come to having all life wiped out. In fact, in the 19th century, geologists thought that life had been wiped out and a separate creation had occurred to start the Triassic. What really happened, and how, are the subjects of _Extinction: How Life on Earth Nearly Ended 250 Million Years Ago_ (Princeton University Press) by Douglas H. Erwin, Senior Scientist and Curator of the Department of Paleobiology at the Smithsonian. He has made the end-Permian mass extinction his research interest for the past twenty years, and has traveled all over the world to the fossil beds and geologic boundary layers remaining from around the time of the catastrophe. Looking back so many millions of years ago is not easy, and the picture is not as clear as that of the dinosaur extinction. Erwin's book, however, is a fine demonstration of how geologists and paleobiologists have come to some admittedly limited understanding of what happened.
There are many factors that have been suspects in the great killing, and Erwin likes to think of himself as a detective out of Agatha Christie set to finger the actual culprit. It's not that easy, of course. Catastrophic explanations for the end-Permian abound, and Erwin's book is an examination of the more likely causes, about six of them. Of course, a main one, borrowing from the success of the impact explanation of 65 million years ago, is an extraterrestrial impact. It is certainly a plausible explanation, since it is accepted as the cause of the more recent extinction. There are problems, however. The impact that wiped out the dinosaurs left clues like an iridium layer in geological strata (there is lots of iridium in meteorites, not so much on Earth) and "shocked quartz" impact crystals, but such clues are lacking for the earlier event. Another explanation might be volcanism, resulting in dust and acidic chemicals and basalts that cover a countryside "much as honey fills in the roughness of an English muffin." Yet another is that continental drift (plate tectonics) was causing collisions at the time, forcing species that had not previously met each other to compete, and changing the global climate by newly formed landmasses. Vast glaciation may have caused cooling and a decrease in sea level. Perhaps there was a drop in oxygen levels of the oceans. Maybe sea levels dropped and caused a huge release of methane from sediments.
He has not, however, wrapped everything up, as, say, Hercule Poirot might. He does, indeed, call his own proposal at explanation the _Murder on the Orient Express_ hypothesis, based on Agatha Christie's book which is a who-didn't-do-it rather than a whodunit. The explanation calls on aspects of many of the other explanations, but Erwin admits this makes it hard to test. One of his colleagues had dubbed it "Erwin's kitchen sink hypothesis", and, as Erwin says, was not being complimentary. There are implications for our own times in this story, since we are now in another period of great extinctions and our climate may be changing irrevocably, but Erwin does not stress these. His book is a fine summary of current thinking on the extinction. Readers will come up against sentences like, "Some surviving ammonoids with extreme morphology died out in the Griesbachian, but new Dienerian ammonoids were more similar to the norm..." (all the terms are well explained, but will be new to most readers), but then a few pages later readers will learn that the "quality of many Early Triassic fossils is really pretty lousy." There may be fewer hard answers here than in a murder mystery, but the explanations about how scientists came up with ideas about the extinction make this a fascinating look at experts confronting profound and distant mysteries.
on June 22, 2006
Some months ago, I read (and reviewed) the book Mass Extinctions by Hallam and Wignall (whose names appear frequently in Erwin's book). I had difficulty with that book because it had a lot of technical terms with which I wasn't familiar. When I learned of Erwin's book, which deals with only one of the major extinctions, I thought it would be helpful because it wouldn't cover as many different topics all in the same place. It turned out to be even easier than I expected, because Extinction was written for non-scientists. Anyone who is interested in mass extinctions should be able to read it.
While I was disappointed at first, Erwin used a method that made the book worth reading for me: he gradually introduced enough technical concepts to explain how the scientists are examining the evidence. It is gradual enough for most readers to absorb the material as they go along.
For example, the division of time in which the extinction occurred is called the Permian period. This has two subdivisions of interest here, called the Guadalupian and Lopingian epochs, and there was really one extinction in each. One occurred in the subdivision of the Guadalupian epoch called the Capitanian stage, and the other occurred in the Chinghsingian stage of the Lopingian. By the time you get to the post-extinction recovery, near the end of the book, there are even subdivisions of the stages. This kind of thng made Hallam and Wignall hard reading but, as I said, Erwin introduces them gradually. In the early part of the book, he just calls the extinctions the first and the second; by the time you get to substages, you'll be ready for them. Also, Erwin has charts of the time periods. I recommend you keep a bookmark at each chart. This is just one example of how he introduces technical matters gradually.
Another thing that threw me with Hallam and Wignall was the consideration of ratios of carbon isotopes. Erwin gives a much longer and clearer discussion. But it is still necessary to read carefully. At one point he says that an increase in delta-13-C indicates more inorganic carbon, but shortly later he says that an increase indicates that more organic carbon is being deposited. Keep in mind that the first refers to carbon in the seawater and the latter is carbon in organic sediment. The carbon in limestone deposits isn't affected by life processes and so the carbon isotope ratio matches that of the seawater. Since limestone is carbonate, this explains his later distinction between carbonate and organic carbon. This is the only spot in the book where I had to work hard at understanding. If my discussion looks too technical, remember that Erwin spreads it out over a few pages.
Other reviews pretty much describe the contents, so I'll skip those details. If you're looking for an introduction to the causes of extinctions, I recommend this book. If you already know something about delta-13-C, marine anoxia, et al. and you're looking for a systematic, technical treatment, consider the Hallam and Wignall book. Click above on "See all my reviews"; it's low on the third page, with only Hallam's name. If you finish Erwin's book and feel you want more, Hallam and Wignall might be right for you.
[Added 4 July 2006] I have just finished rereading Hallam and Wignall's book. With the knowledge gained from Erwin, and from my first reading of H & W, I found it much more readable. I still recommend Erwin for readers without some background in the field, but I am even more convinced that many who have read Erwin will like H & W.
[Added 31 Jan 2007] I just noticed that I didn't say anything about evolution, even though my main interest in extinction is in its influence on evolution. In the wake of the Permian extinction, after a period of slow recovery, there was a period of very rapid diversification (i.e. evolution) during which total diversity reached the level it would probably been at if the extinction hadn't happened. But the particular forms were very different from those before the extinction. Other authors have called this period the birth of the modern sorld.
on May 4, 2009
Educated as a geologist, I have read extensively on the issue of mass extinctions and am familiar with the many arguments about the ambiguities of just what happened at the end of the Permian. Taken in by the title of the book, I hoped to get better educated on what the leading hypotheses are. I did get that from this book but was ultimately disappointed that Erwin would not plant a flag in the ground about how HE really felt about this issue.
In that respect, the sub-title is misleading. Instead of "How Life on Earth Nearly Ended 250 Million Years Ago", it should have said "Ideas about How Life on Earth Nearly Ended 250 Million Years Ago".
Erwin also does not go into some of the more intriguing concepts bandied about regarding the recovery from that extinction. For instance, why is it that the major reptilian group to emerge from the event, the dinosaurs, were so efficient at using oxygen? Evolutionary pressures driven by an extended period of low atmospheric oxygen favored them it seems - yet he does not really discuss this aspect at all.
I was very impressed with how Erwin brought together the details of the work now being done at the Permian Triassic boundary but I did not find the book very satisfying from the larger perspective.
on November 4, 2013
The title of the book is "Extinction: How Life on Earth Nearly Ended 250 Million Years Ago" and the author is Douglas H. Erwin. Our planet has a sometimes very violent history, which is recorded in its rock strata. How do we decipher it? Geology is one major discipline with the tools, whereas paleontology is another. Strata record a chronology of the Earth based on the premise that older strata lie beneath younger strata. Scientists have compared strata from around the world and matched up similar time periods (i.e.; identical strata). Multi-cell plants and animals have left their fossils in the last half billion years of the Earth's history. Three major divisions (eras) became evident to scientists: the Paleozoic Era, the Mesozoic Era, and the Cenozoic Era. The first era contains the story of primitive multi-cell animals, first fishes, first amphibians, and first reptiles. Then the mother of all global extinctions occurred and wiped out 95% of all species. The next era (Mesozoic) was the age of the dinosaurs and it lasted well over 120 million years. Again, a global extinction wiped out the dinosaurs and several other species. Since that mass extinction event 65 million years ago, new kinds of animals have repopulated the Earth, namely mammals and birds. This book focuses on that major extinction at the end of the Paleozoic and teaches what science can deduce about it.
That end-Paleozoic transition is named the Permo-Triassic extinction. The name comes from the last period in the Paleozoic (the Permian) and the first period in the Mesozoic (the Triassic). We are talking about an event that happened one quarter of a billion years ago. The task is extremely challenging because the surface of the Earth is remodeled continuously by erosion, mountain building, subduction of ocean sea floor plates, and other geological processes. The author has done a thorough job of providing the reader with an understanding of the tools available to attack the problem. These tools include radioisotope dating techniques, paleontology considerations, the carbon cycle, which can be used to evaluate conditions in the distant past by measuring the relative amounts of C12 and C13. The author liberally gives credit to the many individual scientists each working on a aspect of the bigger problem. He also examines the different hypotheses that have attempted to explain what caused the mass extinction.
Professionals, such as geologists and paleontologists, would be likely to buy this book because they will acquire a powerful reference tool. Moreover, they would make the purchase, knowing in advance, that they can understand the vernicular of the extinction scientist. For others less specialized, the jargon could be an obstacle to understanding the book's contents. Dr. Erwin does attempt to explain the technology to the novice readers and does a good job of it. However, sometimes he forgets that this audience exists and seems to be communicating with his peers alone. The book has photos, charts, graphs and other visual aids which help clarify the textual messages. The extinction was a global event, but there are only a few places on the Earth where evidence still exists. Consequently, the author takes us to China, South Africa, the Rocky Mountains, and other places where he can support his narrative with evidence and examples.
The author presents arguments for the several different hypotheses explaining the great extinction, but does not lock on to any particular one as the best hypothesis. He gives an unbiased voice to each of them, with cautionary comments to the readers about obvious flaws in the reasoning or new evidence which negates previous scientific beliefs. Thus, the book is an unbiased account of what science has been able to learn about the Permo-Triassic extinction. I felt that I learned a lot about mass extinctions in general and this extinction in particular. I know that I should reread it at some future time to better lock in my understanding of the book's contents. Hopefully, you can decide from my review whether or not you would want to learn what this book has to teach you.
Ralph D. Hermansen, November 4, 2013
on February 14, 2012
The author does a fine job explaining the possible causation of the Permo-Triassic extinction. He keeps the necessary technical babble to a minimum, making this book (mostly) accessible to any lay person. Some of the charts were confusing to me, but I got the gist of things. The chapters are well organized, and his method of making the book a "geological mystery" is very well executed.
I also appreciate the author's introspective style; he doesn't have all the answers, nor does he pretend to. Credit is given to fellow geologists for their field and lab work, and overall the reader gets a good sense of life (and death) on this planet 250 million years ago.
If I were a paleontologist, no doubt this would be a 5 star read. As is, it's an excellent overview of a very intriguing period of time in our planet's history that anyone can enjoy, regardless of their level of knowledge for the subject at hand.
I am keeping this book nearby as I plan to re-read it in the near future; I found it that engaging.
on August 20, 2006
Reading this book gave me the same sort of headache that reading Paul Gallico's THE POSEIDON ADVENTURE did -- I kept stumbling and wincing over badly puncutated sentences, mis-applied terminology, and a host of other stylistic and grammatical problems probably due to the fact that instead of properly proofreading this first edition work, somebody relied on a spell-checker to do the whole job and ignored everything else. That said, however, like THE POSEIDON ADVENTURE as well as Gallico's other work -- and like the work of Ceremonial Magickian Aleister Crowley, essentially an engineer writing for other engineers who would be able to fill in the blanks and make mental corrections of technical boo-boss as needed, not for a public who neither know nor care about the nuts and bolts of the Magickal aspects of reality -- I couldn't put the damned thing down. Like Gallico, Erwin has a powerful sense of story, far and away THE essential ingredient of a great literary work, and what is paleontology all about, anyway, but the study of the long, long story of Earthly life? He also has just as powerful a sens of humor, as well. And his analysis of the problem and possible avenues to its ultimate solution -- an understanding of what caused the End-Permian catastrophe -- is meticulous, painstaking, and fascinating. A wonderful read. I hope that by the time the paperback version comes out the editorial problems will have been corrected -- but even if not, I'll buy it anyway. This is a must for the library of anyone who has any interest at all in the history of living creatures, their tenure on Earth, and what their story has to tell us about our own probable futures. I give it five stars, though maybe with half a point off for the editorial stuff.
on November 27, 2013
I got this book from the library, and decided to buy it afterward as a reference. Erwin does a good job of being objective and presenting all the arguments equally. I've seen some people upset that he doesn't give a definitive answer, but that's not how this type of science works. The events described happened 250+ million years ago, and Erwin gives the reader enough information to have an informed opinion on the topic, and expresses his personal opinions in non-intrusive way, as to not present too much of a bias.
on August 10, 2006
I am in the process of reading this book and am very pleased. I have some background in geology and paleontology but still found the introductory materials interesting and informative without being simplistic. It is very unusual for a distinguished scientist to admit that he - or we - don't know what happened in the Permian extinction, and to invite the reader to develop theories of his or her own, but that is what Erwin has done, and sucessfully.
Do it again, Erwin, with all the other extinctions. You may get a lot more people thinking.