Customer Reviews
Interesting but heavily technical and not very well structured - By: Nick Candoros, 19 Jul 2006 
I was somewhat disappointed by the book. And not because of the subject which could not be more interesting: What happened at the end of the Permian (c.250 million years ago) & over 95% of all living organisms became extinct? The problem nags paleontologists for decades & no thoroughly satisfying scientific explanation isin view.
So, why the disappointment? Firstly, I was expecting a more biological approach instead of the physics/chemistry/geology one I got. I understand of course that a problem of this magnitude covers, by default, multiple scientific disciplines, but that did little to alleviate the difficulty I had, navigating many of the book's passages. And I stayed positively starved from the point of biology. Only one or two of the period's various complex ecosystems & food webs are describedin some detail. There are additional biological glimpses,in various chapters, lostin a sea of Geology & Climate data, but I was expecting much morein that line.
Secondly we have a problem of structuring. The authorin the first chapters presents,in summary, the various proposed theories about the whys & how's of this tremendous extinction (extensive volcanism, giant meteor(s), oceanic anoxia etc.) but then fails to develop each theoryin detailin a consistent manner e.g. one per chapter. Of course he touches them within the book but again I did not manage to get a good grasp of the pros & cons of each scientific proposal. The final chapters try to summarize things & present the author's personal pet theory, but the whole point is somewhat muddled.
The text is well written, the subject is definitely hot, the data are mostly there but you have a rough time structuring themin order to gain a measure of systematic knowledge. And the biological data poverty does not help a bit.
Resetting the clock - By: Stephen A. Haines, 30 May 2006 
Any scientist who opens [and closes!] a book by saying "We [I] don't know!" is worthy of your attention & respect. Too many others have taken up a theme & defended against all comers. Erwin's examination of the catastrophic close of the Permian Age is complete, admirably researched & 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 hiddenin a cave for a generation. Erwin opens with a brief overview of that event, reminding us that extinctions, particularly "impact events", have loomed largein discussions of the history of life ever since Walter & 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 shiftsin benthic populations. The seas rise & fall - for a variety of reasons. Glaciation takes up sea water & leaves continental shelves high & 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 - & where not. When did the Siberian "traps" form? How much lava spewed from that rift, & 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 & 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 & 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 flawsin a previous effort. The strain wasn't discordant, but the composition needed refinement.
Erwin fastidiously acknowledges his contributors. Jack Sepkowski comesin for deserved accolades, as do Bruce Rubridge, Yugan Jin & many others. Their methods, results & 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 liesin 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 - & 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]
