31 of 35 people found the following review helpful
Roger McEvilly (the guilty bystander)
- Published on Amazon.com
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 it's climate change (drying of the Mediterranean, prevalence of ice ages), evolution of man (from these two possibly), and now carbon dioxide emission.
The end Triassic, along with the end Permian, are the least understood extinction events. Peter Ward takes us to the red sandstones of the Karoo (P/T), the Queen Charlotte Islands off the coast of Canada (end Triassic), and Soviet Georgia in the former USSR (K/T), to unravel some of these mysteries. The last portion of the book looks at the present extinction event-with man as the major influence. An extended discussion of the Hawaiian islands is given.
Peter Ward mentions that the start of the Triassic worldwide often contains redbeds, even near the poles-suggesting hothouse conditions. From my experience in New South Wales, Australia, this is true. The start of the Triassic in NSW is interesting in that it seems also utterly barren of coal-despite alot of coal through the Permian. Something happened-the organisms were all dead, apparently. There are alot of redbeds at the boundary too-hothouse conditions-even though New South Wales was near the poles at the time. It is interesting to see these sort of patterns worldwide, something strange indeed seems to have been going on at the start of the Triassic/end Permian.
One disappointment, also pointed out by others, is the lack of good diagrams, photos and the like. There are a few, but there could certainly be more. Mr Ward-rock sequences are visually interesting, as are fossils and diagrams-put a few more in please! And what about the Ordovician extinction, and others?
A good read, and a good guide to updates on extinction scenarios.
11 of 11 people found the following review helpful
- Published on Amazon.com
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 really forces the conclusion that people are the cause of these extinctions, but he does present some pretty incriminating data pointing to our species as the culprit. Mostly the evidence is circumstantial. A natural paradise exists without humans, humans arrive, mass extinction ensues. It happened in Hawaii (both with the indigenous population, and later with European invaders), the America, Australia, Madagascar, New Zeeland, and so forth.
Ward also points to studies that help illustrate the complexity of extinction. Most extinctions are not caused by a single factor. And (as in the case of Madagascar) extinctions don't have to follow necessarily from hunting or otherwise deliberate killing of animals. They can (and do) happen because of habitat destruction and habitat compartmentalization and division. Something as simple as building a road through a wilderness area can be enough to tip the balance.
The cover of Ward's book shows a stark and barren landscape with dry riverbeds streaking through the sparse, brown bush. These rivers no longer run. The symbolism for extinction is deliberate. We all know that organisms and species die, but we still morn their passage. And when they die an untimely death, when their demise could have been prevented, it leaves a bitter taste of remorse and regret.
I remember when I first learned about extinction. I was a kid, and my mother told me there used to be this flightless bird, about the size of a turkey or a chicken, and how it no longer existed because people hunted it to extinction. I remember the deep sense of remorse that I felt - cheated is a good way to describe it - at the fact I could only see this amazing creature as a stuffed exhibit in a museum. Later, when school kids laughed about how the "stupid" dodo had gone extinct, I felt a shudder of shame for my species.
As I read this book I found my self repeatedly wishing that the knowledge found between its covers could be imparted to every one of the politicians responsible for safeguarding what's left of our environment, and realizing in bitter disappointment that, with the election of radical Christian fundamentalists who now control the Congress and White House, the rush toward extinction has only shifted into a higher gear. As I tell my kids, enjoy the wilderness you see. Climb these glaciers, breath deeply the mountain air, because it is quickly disappearing. I'd call Ward's book valuable and informative, and hopefully it will spur a few to try and stop the onslaught, but ultimately I found the story depressing. Extinction really is forever.