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39 of 39 people found the following review helpful:
5.0 out of 5 stars
Theory of Mass Extinctions for the Serious Beginner, August 9, 2006
This review is from: Catastrophes and Lesser Calamities: The Causes of Mass Extinctions (Paperback)
Other reviews on this page give a fair idea of the contents of this book and so, as with most of my science reviews, my main goal here is to describe the technical level so that potential readers can decide if this book is for them. (If you're interested, you can click above on "See all my reviews" for more. There are at least two pages.) This is especially urgent since one of the previous reviews (of the paperback edition) says that Hallam "keeps his use of professional terms within the reach of the basic reader..." while another reviewer (of the hard cover) says the book is more appropriate for specialists than for general readers. I have seen only the paperback and it has a LOT of jargon, words such as "Frasnian", "tectonoeustatic", "chronostratigraphy", "brachiopod", and "paraphyletic". I still say this is a book for beginners because it doesn't require much prior knowledge. All of the terms the reader will need to know are defined in the book; many are defined more than once, in case the reader has forgotten in the meantime. (That will often be the case.) One doesn't need to know mathematics, geology, chemistry, or the history of life. There are also a great many undefined terms but, in general, there is no need to know the definitions. They are mainly names of kinds of organisms and the point Hallam is making is that a lot of kinds of organisms went extinct at the same time. For example, it doesn't matter if you don't know how rugose corals differ from other corals; the point is that the kinds of animals that built reefs before the Permian extinction disappeared in that extinction. Some readers will be uncomfortable at first with getting the gist of an argument without understanding all the words, but I think most will get used to it. Hallam also has a very good chapter on the effect of mass extinctions on evolution. In particular, a pair of graphs shows a remarkable change in diversification of marine life about the time of the Permian extinction and another in land life at the time of the K-T extinction. I have always been interested in evolution, so this is the most interesting thing about mass extinctions for me. And there is a final chapter on the Holocene mass extinction, which is currently being carried out by humans. There are two other books on mass extinctions which I have read and reviewed and which may be of interest. One is by Hallam and his colleague Paul Wignall. It covers essentially the same ground as the current book, but it is at a more technical level and it assumes the reader knows many of the terms that are used in the current book. The specialists that another reviewer mentioned would be much better off going directly to Hallam and Wignall, as would anyone who I familiar with the 5 words I cited above. Readers who absorb much of the vocabulary in Hallam might well like to go on to Hallam and Wignall. The other book is by Douglas Erwin. This is more technical than Hallam but less technical than Hallam and Wignall. It also covers only one mass extinction, that of the end-Permian, and so there is less vocabulary to keep track of. The end-Permian is the most exciting for me, not only because it was more massive than the others, but even more so because one of the groups that was nearly wiped out was the the synapsids, the ancestors of mammals. One more extinction in that group and we might not be here. Erwin also has an excellent discussion of the significance of carbon isotope ratios. In sum, if you want to learn the science of mass extinctions and not just descriptions, if you know only a little about palaeogeology and marine palaeobiology, if you like to work at learning, and if you're not intimidated by a lot of new words, This book is an excellent place to start. Some readers will find it so complete that they won't need more.
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21 of 21 people found the following review helpful:
5.0 out of 5 stars
Supurb overview on the topic of extinction, June 17, 2006
This review is from: Catastrophes and Lesser Calamities: The Causes of Mass Extinctions (Paperback)
Catastrophes and Lesser Calamities by Tony Hallam is a well written book on the topic of biological extinction through time . The volume is essentially a rewrite of the book he and Dr. Wignall wrote together in 1997 (Mass Extinctions and their Aftermath). While the latter is far more technical and probably more than the average person with an interest in paleontology and extinction events is willing to undertake, the present volume is written very much with the a vocational reader in mind. The book has a very readable style, revealing the author's erudition in its sentence style, vocabulary choices (my favorite is "depauperate" with respect to a description of the diversity of a particular fauna), and thorough knowledge of the recent pertinent literature. He keeps his use of professional terms within reach of the basic reader and provides a glossary of terms at the end of the book. While he has some "attitude" with respect to certain issues, he addresses everything in a thoroughly gentlemanly manner, giving credit to the work of others, and when he disagrees with findings makes his point graciously and with evidential support. Students writing papers would do well to study his style and approach to argument. The earlier book with Wignall addressed extinction as a series of specific events. It looks at each event, discussing the date, type specimens, and facies locales throughout the world that support the likely diagnosis of mass extinction and reviews the scientific data that suggests how they might have come about. The present book looks at extinction as a process that effects life and evolution through time. While specific events are discussed in an organized way, the author focuses more on the nature of proposed extinction processes. The most commonly and widely known of these causes are the bolide impact, anoxic aquatic or atmospheric conditions, volcanism, and climate change, each of which is examined in depth using specific extinction events to discuss the data. The section I found most interesting was "Pulling the Strands Together." This was because it reminded me of other authors I've read on other subjects, the topics of which seem to have implications for extinction as a process. One is Stuart Kaufmann's work on self organized criticality which discussed, among other things, a topography of fitness within a set of parameters. He introduced a diagram illustrating, through the rise of peaks from a baseline terrain, that life tends to organize itself in such a way as to make optimal use of the fitness terrain. He notes that, when conditions are altered especially when rapid, those at the peak are not able to hop from one peak to a better one. Their failure to adapt brings about extinction, and others along the lower slopes make a transition to a new peak fitness profile. As Hallam notes, catastrophes may occur too quickly for many taxa to adapt in a Darwinian manner, which leads to disappearance. However, where change is slow enough some taxa that seem to have disappeared may in fact simply have evolved into a descendant species. They sort of back down the old fitness slope and head off in a new direction. Another author that is brought to mind is the theorist Per Bak, who studies self organized criticality and event probability. The discussion of periodicity/episodicity of extinction in Dr. Hallam's work reminded me of Dr. Bak's discussion of earthquakes, landslides, and similar events. In this case, the author notes that the frequency of occurrence of any possible event will lie along a curve that measures the probability of a given magnitude. In this instance, extinction might be seen as ranging from extinction of a single of species to the end of all life on earth. In short, Bak believes that all events that can occur will do so, but that they have a different probability of doing so. As with the disaster in New Orleans during Hurricane Katrina, it isn't a matter of "if" but of "when" the event will occur. The events as they occur through time, however, form an irregular curve with many small peaks punctuated with the random introduction of a few very big ones. The issue for disaster planners and others is that of prediction and preparation, so an effort is made to find a "periodicity" in the data that isn't necessarily there to find. This sounds very much like Dr. Hallam's discussion of the attempts to pin down a periodicity in the data of extinction events. Humans are very good at seeing patterns in random data, but ultimately all that can be said is that "if it has happened, it can happen." I'd recommend the book to anyone with an interest in paleontology, paleoecology, and extinction events. It would make a lovely book for an introductory course on earth history, or in paleontology, and an excellent syllabus entry for a course in earth science for teachers. A wonderful book, full of information, and well written.
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15 of 16 people found the following review helpful:
5.0 out of 5 stars
Another Nail in the Coffin of Simplicity and Uniformitarianism, December 3, 2007
I guess this is a tough little book for some. Certainly other reviewers have said so. It's not mere armchair science or Discovery Channel drama. Rather it's a lucid and well supported statement of an hypothesis, that the five great extinction events at the ends of the Ordovician, Permian, Triassic, Cretaceous and Devonian epochs did not all have the same cause, nor did they all occur in the same time-frame, but that they all can be correlated to major changes in sea level, which also did not have uniform causes. The corollary to that hypothesis is tantamount to SJ Gould's theory of 'punctuated equilibrium', i.e. that extinction events have played a major role in evolution of species. Furthermore, Hallam examines evidence that extremely high sea levels have (perhaps invariably) resulted in anoxic oceans - dead oceans effectively. Although Hallam makes no mention whatsoever of the current anthropogenic climate change, or of any news-worthy data less than 10,000 years old, it should be clear that his study of past climate-linked changes in sea level has relevance to our thinking about the possible dangers of rapid global warming. I'd strongly suggest reading Hallam's work in conjunction with Peter Ward's study of atmospheric changes on Earth over geological time, and their correlation with mass extinctions and evolution. Ward's two current titles are Under A Green Sky & Out Of Thin Air. The former is more 'popularly' written - quite entertaining, in fact, if you enjoy reading science. Ward is more explicit in his concern with the possible consequences of uncontrolled anthropogenic 'modification' of the air we breathe, which is also the air which controls our climate. I'd summarize more of Hallam's conclusions except that one previous reviewer, Atheen Hills, has already done so quite adequately. The modern understanding of evolution, which we can call neo-Darwinian for convenience, necessarily includes the idea of the contingency of the evolution of life-forms upon the evolution of the planet itself - of the continents in their restlessness, of the oceans which are not so timeless after all, and of the atmosphere which is fragile and susceptible. I'd go so far as to say this is a necessary book for serious thinkers about the history of life, our little three-and-a-half billion year adventure.
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