Rivers in Time: The Search for Clues to Earth's Mass Extinctions

I've read one other book by Peter D. Ward, "The call of distant mammoths," and enjoyed it immensely, so when I saw "Rivers in time," and recognized the author's name I snatched it up right away. The first part of this book contains condensed excerpts from earth's history, with particular emphasis on the famous and most notable extinction events found in the strata. This is preceded, and sometimes interspersed, with a brief history of geology and paleontology. Ward covers highlights relating to methods of dating sedimentary rocks using fossils, and how those techniques are anchored in radiometric dating. Ward introduces some particularly insightful information derived from some of his own field work. This adds a nice touch, and helps the reader understand a little of the flavor associated with being a field geologist. Chapter five for example, describes some work he did along the Pacific Coast of Canada, relating to the mass extinction at the end of the Triassic period - one of the five most catastrophic extinctions during the last 500 million years. The Triassic, Permian, Cretaceous. Ward touches on them all, at least to some extent. Part III is about the Cretaceous/Tertiary event, when the dinosaurs went extinct. Here, as in other discussions, the text isn't just about the mechanics of extinction, but draws upon many ancillary issues that add depth and flavor to the discussion. Particularly interesting is his historical discussion of the scientific debate that led to the currently accepted view that a large comet or meteorite was a major (if not the major) contributor to the Cretaceous/Tertiary event. This part of the book contains interesting tidbits of information that many arm-chair scientists will, no doubt, enjoy. One passage that I underlined was the following: "... the pollen from normal plants found in that [New Mexico] region at the time suddenly disappeared, to be replaced by a pollen and spore assemblage made up almost completely of fern material. Ferns are well-known "disaster" species because they quickly move into and colonize disturbed landscapes, such as newly burned land." Upon reading this I reflected upon the clear-cut that I had wandered across last year, with my horse, riding through the hills of the coast range in western Oregon. It was like a complete swath of destruction laid before me, with the shattered stumps of trees littering the landscape into the hazy distance, liberally punctuated with clumps of ferns. I have a hunch that the real point of Ward's book is found in section IV, "The modern mass extinction." The modern mass extinction started more than 10,000 years ago, and continues unabated today. Ward argues that we are witnessing one of the largest (if not the largest) extinction events in terms of total species lost. He lists several studies, some more alarming than others, indicating that the rate of extinction is probably in the range of thousands of species per year. Ward never reall

I really like Peter Ward's books. He presently serves as my 'geological advisor', as I also am a geologist. He is not as dogmatic as some within the field of mass extinction, since he recognises it is now becoming increasingly obvious that in most mass extinctions, these ancient 'killers' did not act alone. Early arguments in the debate of mass extinction, especially the Cretaceous-Tertiary (K/T) event, were in the form of either/or, (eg volcanism versus asteroid/comet impact), rather than one big event following and/or combining with another. The old argument "one or the other" is now often questioned on the basis of statistics itself. You could just as well turn this logic around-if it so happened, that once in a proverbial blue moon in geological time (which is really long) TWO OR MORE events occurred at roughly the same time-wouldn't this produce a really big mass extinction??. Maybe to exterminate a large number of species against the backdrop of reasonable resistance of life to widespread extinction, more than one major event has to occur. This sort of scenario is supported, for example, by the many impact craters which have been dated and which have produce no mass extinctions. This is the general view espoused by this book.The arguments over statistics is not irrelevant here. Researchers have indeed found that what may appear to be gradual decline in the geological record can be sudden, and vice versa, simply due to such an overlooked thing, for example, as 'sampling' error. For big animals such as dinosaurs it is particularly problematic, because sampling bias occurs in level of exposure, type of rock and degree of preservation for what is already a rarely preserved animal. The geological record is baised in what it tends to preserve, and what it tends to not show. Stratigraphical studies have shown for some time, for example, that vast amounts of time can transpire in a sedimentary sequence, with nothing to show for it, basins are often very dynamic and problematic in this respect. "Thickness" does not often equate wih equivalent time, even in 'quiet' environments. The upshot of all this, and detailed dates on the Decaan Traps for example, have shown clearly, that increased volcanism, climate changes, and at least some general species decline was occurring *before* the clay layer which was produced by impact at the 'K/T boundary'. Maybe we should expect this for 'mass extinction', to produce a real killer blow (ie mass extinction) maybe life has to be wounded first.Peter Ward in this book focusses on four mass extinctions- the P/T, the end Triassic, the K/T, and the present. There is good evidence for similarities -in the end Permian it is suggested to be due to life adapted to ice ages, then increased volcanism and increased CO2 with hothouse, and possible sea level changes. At the K/T it was ocean changes (?), then volcanism and increased CO2, and then impact. At the present a suprisingly similar situation appears to be occurring-now

. . . "but it's considered bad form to discuss it over the patient's sickbed," said Robert Campbell.* Peter Ward has no qualms about discussing this patient's condition. He would probably shout it from mountain tops if he thought anybody would listen. Rivers In Time is a call to readers to join him in diagnosis and therapy to restore the patient to health. Ward vehemently asserts that our planet's in trouble - again. As a paleontologist specializing in extinction, he has deep insight into the circumstances of the mass deaths occurring through Earth's history. He shares these insights with us in vivid prose describing the great dyings of millions of years ago. His descriptions of the evidence surrounding the loss of multiple life forms make compelling reading. He takes us on his journeys through southern Africa, the Canadian West Coast and Pacific Islands. Along the way he shares the evidence of extinctions in deep time, charting events and conditions. This book, however, is not simply a history of extinctions nor a scientific treatise. It is a warning from the past about our future. Ward builds his scenarios in order to examine the evidence surrounding the extinctions in hope of discovering what caused them. In each case he goes on to describe the subsequent conditions in which new life forms evolved. The emerging pattern remains obscure. One fact stands out, however. Life became increasingly diverse in the eras after the sudden loss of major extinction events. Knowledge of diversity is important in understanding what is occurring now, and what that means for the future of our planet and ourselves. And we aren't spending enough resources in learning about how diverse the life surrounding us actually is. That ignorance is a charge against our survival account. No extinction has received more attention than the disappearance of the dinosaurs. Our children know that without their passing, the mammals would have remained tiny, nocturnal, creatures, hidden and obscure. Ward uses the wonderful film, King of Hearts to illustrate how little furry creatures found an empty world in which to proliferate after the dinosaurs were lost. Eventually, those minimal animals evolved into forest dwelling primates who were driven from the trees to become humans. Unlike their predecessors, human animals invaded every ecological niche. With them came revisions of the environment of evolution; rapid habitat loss, chemical pollution and the introduction of alien species.Ward concludes his treatise with some challenging questions. He adopts Edward O. Wilson, Norman Myers and others to posit what has happened, what needs to be done, and what our future options are for planetary survival. The diagnosis completed, now it's time to apply some therapy. The most daunting first step in this therapy is our own self-awareness: what is the condition of the planet? How can we learn more about what is happening? What prescriptions are required to cure the

This book is by far one of the best books I have ever read. I now look at life in a completely different way. I was brought up in a strict Baptist home where the Bible was the only way, after reading this book I don't dismiss God but its sure not how the Bible says it is. Peter writes this book in an informal way, which makes it very interesting; you can almost fell like you are there, taking a beginner like me into a very complicated world. I have discussed this book with others at work and found that no one that I talked to accepts evolution; they all think it's not real. I just feel so much more educated on the subject and thank Peter Ward for writing this book. It was great.