Out of Thin Air: Dinosaurs, Birds, and Earth's Ancient Atmosphere

by Peter D. Ward

For 65 million years dinosaurs ruled the Earth-until a deadly asteroid forced their extinction. But what accounts for the incredible longevity of dinosaurs? A renowned scientist now provides a startling explanation that is rewriting the history of the Age of Dinosaurs. Dinosaurs were pretty amazing creatures-real-life monsters that have the power to fascinate us. And their fiery Hollywood ending only serves to make the story that much more dramatic. But fossil evidence demonstrates that dinosaurs survived several mass extinctions, and were seemingly unaffected by catastrophes that decimated most other life on Earth. What could explain their uncanny ability to endure through the ages? Biologist and earth scientist Peter Ward now accounts for the remarkable indestructibility of dinosaurs by connecting their unusual respiration system with their ability to adapt to Earth's changing environment-a system that was ultimately bequeathed to their descendants, birds. By tracing the evolutionary path back through time and carefully connecting the dots from birds to dinosaurs, Ward describes the unique form of breathing shared by these two distant relatives and demonstrates how this simple but remarkable characteristic provides the elusive explanation to a question that has thus far stumped scientists. Nothing short of revolutionary in its bold presentation of an astonishing theory, Out of Thin Air is a story of science at the edge of discovery. Ward is an outstanding guide to the process of scientific detection. Audacious and innovative in his thinking, meticulous and thoroughly detailed in his research, only a scientist of his caliber is capable of telling this surprising story.

Genres: Science, Nonfiction, Geology, Evolution, Palaeontology, History, Biology

296 pages, Hardcover

First published January 1, 2006

About the author

Peter Douglas Ward is an American paleontologist and professor of Biology and of Earth and Space Sciences at the University of Washington, Seattle. He has written popular numerous science works for a general audience and is also an adviser to the Microbes Mind Forum.

His parents, Joseph and Ruth Ward, moved to Seattle following World War II. Ward grew up in the Seward Park neighborhood of Seattle, attending Franklin High School, and he spent time during summers at a family summer cabin on Orcas Island.

Ward's academic career has included teaching posts and professional connections with Ohio State University, the NASA Astrobiology Institute, the University of California, McMaster University (where he received his PhD in 1976), and the California Institute of Technology. He was elected as a Fellow of the California Academy of Sciences in 1984.

Ward specializes in the Cretaceous–Paleogene extinction event, the Permian–Triassic extinction event, and mass extinctions generally. He has published books on biodiversity and the fossil record. His 1992 book On Methuselah's Trail received a Golden Trilobite Award from the Paleontological Society as the best popular science book of the year. Ward also serves as an adjunct professor of zoology and astronomy.

His book The End of Evolution was published in 1994. In it, he discussed in three parts, each about an extinction event on earth.

Ward is co-author, along with astronomer Donald Brownlee, of the best-selling Rare Earth: Why Complex Life Is Uncommon in the Universe, published in 2000. In that work, the authors suggest that the universe is fundamentally hostile to advanced life, and that, while simple life might be abundant, the likelihood of widespread lifeforms as advanced as those on Earth is marginal. In 2001, his book Future Evolution was published, featuring illustrations by artist Alexis Rockman.

Ward and Brownlee are also co-authors of the book The Life and Death of Planet Earth: How the New Science of Astrobiology Charts the Ultimate Fate of the World, which discusses the Earth's future and eventual demise as it is ultimately destroyed by a warming and expanding Sun.

According to Ward's 2007 book, Under a Green Sky, all but one of the major mass extinction events in history have been brought on by climate change—the same global warming that occurs today. The author argues that events in the past can give valuable information about the future of our planet. Reviewer Doug Brown goes further, stating "this is how the world ends." Scientists at the Universities of York and Leeds also warn that the fossil record supports evidence of impending mass extinction.

Reviews

[Yael · Rating 5 out of 5]

With high levels of atmospheric oxygen, animals can grow very large, and do so because it protects them from predators. When oxygen levels drop, extinctions occur, and numbers of organisms of a given, surviving species drop, but body-plans proliferate as species strive to adapt. More than any other required resources, oxygen is absolutely necessary for the survival of animals, their ability to meet the exigencies of survival, and their ability to reproduce successfully, and it isn't at all surprising that as atmospheric oxygen levels have fluctuated over geological time, evolution has followed suit, mass extinctions and certain evolutionary radiations occurring as oxygen dropped, and more evolutionary radiations occurring once oxygen began to rise. During the Permian-Triassic mass extinction and again at the end of the Triassic Period of the Mesozoic Era, oxygen levels fell so low that animals couldn't manage to climb low hills less than a hundred feet high, running into the same problem that climbers of Mt. Everest did: lethal lack of oxygen in the air they breathed. Animals were locked into relatively small habitats by that the way animals today are coralled their habitats by high mountain ranges, wide lakes or inland seas, and other geographical barriers. As a result, each group of animals barriered from others by low oxygen levels began to evolve away from formerly identical groups of animals in other barriered habitats, thereby giving rise to new species, then whole new genuses, families, orders, and classes of animals in the process.

An elegant and beautifully illustrated presentation of a new theory of the things driving evolution, Out of Thin Air should be in the private library of everyone with a serious interest in the biological sciences, as well as in every public library and bookstore.

[Douglas Summers-Stay · Rating 4 out of 5]

The title is a pun. Adean's hypothesis is that the varying atmospheric oxygen content throughout the ages had profound influence on the course of evolution. Thus, dinosaurs were created "out of thin air."
More specifically, times with low oxygen content are very hard on animals. As the oxygen levels drop, many species die off, and those that survive are those that can rapidly evolve new respiration strategies. In contrast, during times of high oxygen, animals get bigger, fill higher altitude niches, and gradually take on new, more energetic roles. During these times, few species go extinct.
One of my favorite things about the book is how he set the scene for each time period in prehistory. You really get the sense of these epochs being truly alien worlds, with temperature, CO2, oxygen level, all radically different, influencing what kinds of life can be found. During times of low oxygen, for example, high mountain ranges formed essentially impenetrable lifeless barriers between different areas, causing diversification.
I found the reading very engaging. My only complaint was that I was unfamiliar with the names of some kinds of invertebrates, and there were no pictures or descriptions. I'm not sure which of his hypotheses are well accepted by the community. They all seemed plausible to me, but I'm not an expert in the field.
My copy is marked "Salem Public Library" so I'm guessing it was a gift. Thanks, Mom!

[M · Rating 2 out of 5]

How this book merits a LC subject listing of "Paleobotany" is beyond me. And what little topical botany is included is questionable. Ward writes: "during photosynthesis...plants liberate free oxygen as a by-product of the break-up of carbon dioxide..." (p. 36). Not so much.

He also makes a curious statement about cyanobacteria (pp. 34-35) that seems to ignore the multiple biochemical fates of photosynthetically produced sugars in aerobic organisms.

He has apparently confused "cambia" (secondary meristems) with what he calls "Cambria" ("deeply imbedded vascular tissue" p. 118).

He implies that the type of cellular respiration in plants is the same as photorespiration ("...Like animals, plants need oxygen for life. Oxygen is taken up within the cells during photorespiration...").

Perhaps fact-checking gets in the way of prolific writing, and this is a lesson for us all.

[Peter Bradley · Rating 5 out of 5]

Please give my review a helpful vote - https://www.amazon.com/review/R2468VW...

Out of Thin Air by Peter D. Ward

If you love “Gosh-Wow!” science – science that expands the mind, presents the big picture, stuns the imagination – then this is one of the “Gosh-Wowiest!” of “Gosh-Wow!” science.

Author Peter D. Ward starts with an unusual and striking premise that leaves the reader walking on existential egg-shells. Ward posits that the big, big driver of evolution has been the periods when the oxygen content of the Earth’s atmosphere plunged to levels of extreme oxygen deprivation, such that a creature during some of the Earth’s geological epochs living at sea level would experience the same oxygen deprivation that today someone climbing to the top of Mr. Everest would experience. Ward offers this example:

“At the end of the Permian just living at sea level would have been equivalent today to breathing at 15,000 feet, a height greater than that found atop Mount Rainer in Washington State. Thus even low altitudes during the Permian would have exacerbated this, so that even a modest set of hills would have isolated all but the most low-oxygen-tolerant animals. The result would be a world composed of numerous endemic centers hugging the sea-level coastlines. The high plateaus of many continents may have been without animal life save for the most altitude tolerant. This goes against expectation based on continental position.”
And:

“The drop in oxygen did more than make mountain ranges barriers to migration. It made most areas higher than 3,000 feet uninhabitable during the late Permian-Triassic time interval.”

Stop there for a moment….basically, a low coastal mountain range would have been an impassible barrier to life in the past. What kind of alien planet are we talking about?

Ward explains that scientific modeling of atmospheric oxygen content provides circumstantial evidence of oxygen levels. The reason for the changes in atmosphere levels has to do with the rate of burial of organic carbon and sulfur bearing compounds. Sometimes carbon is buried by plate tectonics, or in the case of the Carboniferous, by the massive evolution of vegetation and the lag in the evolution of bacteria able to consume the complex chemicals in the “recently” evolved trees. The result was the massive lock-up of carbon in buried forests that we now exploit as coal. The result of that, plus the massive production of oxygen by plankton and vegetation, raised oxygen levels to an unseemly 30% which was responsible for the development of huge insects and massive forest fires. Ward describes the period as follows:

“The first noticeable characteristic is the color of the sky. It is a polluted yellow-brown, irrespective of weather; only in high winds does the air clear and then soon it muddies again. This is due to smoke from giant fires perpetually raging and new ones set alight with each lightning strike hitting the extensive forests of the temperate and tropical regions. But there is more than soot in the air; there is fine wind-blown dust as well, accumulating as loess, or glacial front deposits. The air is cold over much of the planet, for this is the time of one of the most extensive glaciations in Earth’s history, with ice caps at each pole and continental glaciers reaching icy fingers across the land as they snake downward out of the mountains onto the plains and river valleys. Where there are forests we find unending vistas of conifer-like trees, for the gymnosperms have by now evolved and have swept away many of the earlier dominant plants. No longer do tall but shallow-rooted primitive trees like Lepidodendron dot the landscape. It is much more familiar, or familiar at least to those of us who now live in the high northern or southern latitudes where pines and fir trees dominate the forests.”

The result of this was mayflies with 19 inch wingspans and spiders with 18 inch legs.

Alternatively, there have been times when volcanoes and traps have polluted the atmosphere with carbon dioxide and other noxious gases, and oxygen levels have lowered to catastrophic levels. Ward’s thesis is that the times when oxygen levels have been reduced to extremely low levels are the periods marked by the “Great Extinctions.” Further, during these periods, evolution favors those species that obtain better results in respiration. Sometimes these changes involve changes in the apparatus of respiration, but other times, the advantage is given by morphological changes. Thus, for example, lizards have a poor morphology for breathing since their side to side motion means that they cannot run and breathe at the same time. This is not much of a problem when oxygen levels are high, but when they drop the organism that can make an improvement on respiration can hunt, evade and reproduce better than the competition.

One morphological change that worked was the development of an upright stance on the part of the early dinosaurs. Being upright, their breathing was not affected by the lizards side-to-side motion and they were able to run and breath, which was a major advantage when oxygen levels increased and those animals that were already pre-adapted to better respiration were able to exploit their new morphologies for other advantages.

One of Ward’s thesis is that the primary reason for the change in body plans is respiration, with all other considerations coming in as a lucky second. Thus, crabs evolved during another downturn in oxygen. The primary advantage of the crab morphology isn’t the obvious advantage of armor and an unexposed thorax, but the fact that it creates a better plan for sucking more water over the gills in order to extract more oxygen out of more water.

Ward also provides an idiosyncratic theory on the “warm blooded dinosaur” debate. Ward does not think that dinosaurs were necessarily warm-blooded. They evolved in a unique period of low oxygen and high temperature, such that being warm blooded all the time would not have been an evolutionary advantage. Ward writes:

“And the conditions of the Triassic may have been such that, thanks to highly elevated carbon dioxide levels, greenhouse heating may have kept the temperatures virtually equal day and night—and hot to boot. The Triassic climate was one suited for reptiles—hot. That heat would actually have been a problem for very large endotherms. Large dinosaurs (greater than a ton, such as most sauropods) would have overheated in even moderate temperatures, and the Triassic environment was anything but moderate. So here it is suggested that cold-blooded dinosaurs would have been a condition actually more favorable than warm-bloodedness for dinosaurs, mainly because of the large differ ence in oxygen needed while at rest. In the Triassic and into the Jurassic, ectothermy would not have relegated dinosaurs to a sluggish life style. With the absence of nasal turbinals characteristic of modern-day endotherms, the case for ectothermy is stronger than that for endothermy.”

And:

“What are we left with? A kind of animal unknown on Earth today. An ectotherm with phenomenally rapid growth rates and a lung system that, while inferior to the best of modern-day birds, was more efficient at extracting the thin oxygen available than those of other denizens of the day. Superiority of the dinosaurs in the latest Triassic and then into Jurassic through the Cretaceous was made possible by being better than everyone else. A return to those times might be surprising indeed, with animals showing behavior that is not mammalian or avian, not a sluggish existence but something in between. Perhaps the earliest dinosaurs were something like lions, sleeping 20 hours a day to conserve energy because of the low oxygen, but when hunting doing so actively, more actively than any of their competitors, which would have included the nondinosaur archosaurs, the cynodonts, and the first true mammals. All they needed to be was better than the rest. Clearly they were.”

This is fascinating, engaging book. The writing is journeyman. I found the first part somewhat lackluster, but one Ward got into the evolutionary perspective it was absolutely fascinating. For me the changing oxygen levels seems somewhat speculative, and I wondered how much crackpottery there is in Ward’s thesis, but Ward hammers away with example after example, such that, by the end, granting him his inconstant atmosphere, I’m willing to keep an open-mind. I wonder whether 30 years from now, Ward’s view of Earth’s atmosphere is going to be as commonplace as the idea that the continents slide around like pool balls. My biggest take-away was the inconstant nature of the Earth’s atmosphere, and the possibility that the Earth’s future might, like it’s past, be oxygen-starved.

[Noel Roach · Rating 3 out of 5]

Ward puts forward the thesis that the variation in the partial pressure of oxygen over the past 540 million years since the Cambrian Explosion has been the major driving force (or certainly one of the big ones) in evolution. I have to say I was not convinced of the "major" part. Not that I have any specific scientific background in the area. It being 2014 now, 8 years after the book was first published, I wonder how widely Ward's theories have been accepted by the scientific community. In each chapter Ward puts forward a specific hypothesis variation of his overall thesis for the geologic period(s) being discussed, but then he never tests it. Science is all about the *best* theory *so far*. So I felt Ward should have been telling me why his new theory was *better* than everything else that has come before. To be a little specious, 'intelligent design' is a good theory, there are simply a lot better ones around that explain more observable facts. A new drug that cures 25% of people who have a disease is great, except when there is already a drug on the market that cures 75% of sufferers.

A very interesting and easy read. I particularly enjoyed Ward's use of the visitor on an airplane/submarine tour to set the scene at the beginning of each of the first few chapters.

[John Shaw · Rating 3 out of 5]

I read this book to refresh and improve my understanding of the defining aspects of geological eras and historical trends in atmospheric composition.

Ward certainty presented this information well, and made compelling arguments about the causative links between oxygen concentrations and major milestones in biology. To what degree these hypothesis have held since publication, I'm unsure, though respiration as a key driver of evolution makes a great deal of sense given the paleontological evidence provided.

I learnt a great deal about the evolution of respiratory systems (birds and cephalopods in particular), which was an unexpected bonus. I have forgotten a great deal more of the minutiae about which Mesozoic reptile evolved into what - it was a dense read at times - but the detail tied in to each of the hypotheses well.

Definitely a worthwhile read given the scope of the content.

[Clare · Rating 3 out of 5]

Using scientific research from varying sources, including his own, the author sets down hypotheses on how the amount of oxygen in the air throughout earth's history effected the evolution of the fauna (and to a lesser extent the flora) of our planet.
Sometimes the prose reads more like a textbook but there are also places where the author takes the reader on a "tour" of the time period he is describing in a particular chapter. When he uses that format it really brings to life how things looked at different prehistoric times. Every once in a while there is even a bit of sly humor when describing some of the animals and how they would be reacting to either low or high oxygen content.
This was quite an interesting look at a world no man ever saw and illustrates how challenging it is trying to find out about life millions of years ago.

[Luis Brudna · Rating 4 out of 5]

O livro é sobre como as variações da quantidade de oxigênio na atmosfera terrestre influenciou a evolução biológica. É complicado para quem não tem conhecimento sobre geologia e/ou evolução das espécies.
O Peter Ward parece que gosta de lançar novas ideias e hipóteses. Li o livro mais como um suporte para um conhecimento básico sobre o oxigênio terrestre e suas variações nos mais de 4,5 bilhões de anos de história da Terra.
(li o livro em inglês)

[Becky · Rating 4 out of 5]

Well written with a really interesting premise, but a few too many typos and some questionable illustrations.

[Glenn Beard]

I thought it was an excellent book, interesting, explaining the evolution of breathing, a good discussion of extinctions in the Permian and Triassic. It was readable, not too technical for the average educated reader, and written in an interesting manner.
However, it had some weaknesses:
a. The claim that oxygen levels were significantly lower than today was not adequately supported in my opinion. While the prevailing opinion of among many scientist, I have seen others that claim that oxygen levels were quite as low as some have claimed. This claim is central to his book and I would have liked to see more justification of the claim other than the reference to some computer projections
b. Most of the features he said were spurred by the low oxygen (live birth, the respiration system of birds) he acknowledged could have been spurred by other factors, such as colder, drier climate, the demands for flight. It is questionable that the superior lungs of birds gave them the competitive edge he ascribes to it. (He makes minor factual errors - he claims no mammal breeds above 14,000 feet, but there are human towns above 14,000 feet in Chile, and other places. so claim can't be true.)

[Jenine Young · Rating 4 out of 5]

This is a very scholarly book of theories on how oxygen levels changed through history and the changes that resulted.
It read like a thesis, but it worked for the subject.

[Elentarri · Rating 4 out of 5]

Out of Thin Air: Dinosaurs, Birds, and Earth's Ancient Atmosphere by Peter Ward hypothesizes that changing atmospheric and oceanic oxygen levels over the last 600 million years have caused significant evolutionary development, including changes in body plan (morphology), physiology and diversity of animal life.

The author hypothesizes that with high levels of atmospheric oxygen, animals can grow very large, and do so because it protects them from predators. When oxygen levels drop, extinctions occur, and the numbers of organisms of any surviving species drop, but body-plans proliferate as species strive to adapt. More than any other required resources, oxygen is absolutely necessary for the survival of animals, their ability to meet the requirements of survival, and their ability to reproduce successfully. As atmospheric oxygen levels have fluctuated over geological time, evolution has followed suit, with mass extinctions and certain evolutionary radiations occurring as oxygen dropped, and more evolutionary radiations occurring once oxygen began to rise.

I found the material in this book fascinating, informative and thought provoking. The author provides many testable hypothesis and well as a large number of examples involving the structure and comparative functioning of lungs, gills, livers, feathers, hearts (four-chambered vs three chambered), bones, types of metabolism (endothermic vs exothermic), reproductive strategies (eggs vs live-birth) and body posture (bipedal vs lizard and mammal quadruped) in various atmospheric conditions. The impact of plate tectonics and geochemistry (sulfur and carbon cycles) on oxygen levels are also explored. The illustrations were also helpful.

This book is written for intelligent adults and assumes that the reader has some knowledge of the various branches of science, such as biology, physics, chemistry, climatology, and geology.

Overall, a good book and quite insightful, but an editor would have been useful to smooth out the occasional clunky language. I hope the author updates this book with new information soon.

[Esmeralda Rupp-Spangle · Rating 4 out of 5]

This book was engaging, fascinating, and educational. It was pretty dense, and less of a pop science book than you might normally see, but I thought this was a plus not a minus, because even given that, it wasn't dry or dull- assuming the subject matter is of interest to you.
One major gripe I had was that he really needs to replace his editors, there were a few mistakes that really distracted me as I was reading (not factual or data errors, just grammar, etc). Even given that though, I thought it was well researched and elegantly written. I love how he breaks down the sections of the book into eras of time, and in each one takes you on a little tour of what the planet looked like for each of these. His interest and passion for the subject matter really comes through, and I find it positively infectious. What the past can tell us about our future is something I think a lot of people overlook- to our detriment, I'm sure. This isn't the first book of his I've read, and it certainly won't be the last. I highly recommend this book for people interested in paleoclimatology and mass extinction.

[Michael Ward · Rating 4 out of 5]

In the past Earth's oxygen levels have varied between 13% and possibly as high as 28% of the atmosphere. This has happened before and will happen again. Dinosaurs evolved during a mass extinction at a time of low oxygen levels and made it through every other mass extinction until the meteor impact 65 million years ago. One of the attributes that enabled them to live through mass extinctions was their lung capacity which was vastly superior to that of mammals. Birds are descended from dinosaurs and have dinosaur lung capacity and Peter Ward points out that climbers on Mount Everest struggling in the thin air can watch birds happily soaring above them without a care in the world due to their better lung capacity.

When you read this book you realize that we play with the atmosphere at our peril, not just by putting CO2 into the atmosphere but all the other chemicals we put into the atmosphere as well.

This is a fascinating book. Peter Ward makes paleontology interesting and I always enjoy his books.

[Karel Baloun · Rating 4 out of 5]

New models show that all 5 Paleozoic and Mesosoic extinctions were caused by low atmospheric oxygen, which has ranged from 13% to 30% over the last 500m years. Fascinating role for algal hydrogen sulfide in the Permian extinction.

Low oxygen also caused dramatic gains in diversity by providing an existential stress for evolution, and these innovations included: air sac bird lungs (which led the porous boned half of the dinosaurs to dominate the Triassic/early Jurassic), the 4 chambered heart, coming up to dry land and returns to the sea for reptiles. High oxygen in the Carboniferous enabled huge insects, and then in Cretaceous egg shells, endothermy and the mammalian placenta.

Enough fascinating new material, within a clear and persuasive thesis, to overcome a flat, long delivery. Ward frustratingly name drops example species as old friends, while I visit Wikipedia ever 10 pages to understand his point. The visual portraits of past epochs lack vividness and I long for a video or multimedia delivery of the same material.

[James F · Rating 3 out of 5]

When I was growing up a half century ago one of the first biology books I read was Homer Smith's From Fish to Philosopher, which presented vertebrate evolution from the perspective of water balance -- mainly the kidneys. This book reminded me of that; it presents the evolution of animals from the viewpoint of oxygen and respiration.

The author begins from the work of John Berner and others on the history of oxygen and carbon dioxide in the atmosphere, and attempts to explain the evolutionary history of various groups -- especially the dinosaurs -- as adaptations to high or low levels of oxygen.

Some of his hypotheses seem to me to be somewhat exaggerated, but he does explain some developments which would otherwise seem improbable; certainly the changes in oxygen level need to be taken into account. I would be interested in reading more on this topic.

[JodiP · Rating 5 out of 5]

It's because of books such as that I have come to believe I don't read much fiction. How can it compare with the incredible drama of the evolution of life itself? This was a very well-written book which explained terms in understandable fashion. I had no idea about the various respiratory systems of reptiles, birds, and mammals and how this could have impacted the viability of species given the great variability of the oxygen level over the course of eons. I did read Oxygen years and years ago, but don't remember this point being made so memorably. I would like to read more by this author.

[Richard · Rating 4 out of 5]

Ward builds upon the brilliant work by Robert Berneer (Yale) to map out the impacts caused by the wide variations in oxygen levels during the Phaenerozoic. Variation in oxygen leads to extinction when low and diversification when high. Low levels favored the dinosaurs. Ward has a gift for writng that takes you across the alien landscapes and oceanscapes of past geologic ages in a world not yet the familiar one we know.

[Joey Sigmon · Rating 4 out of 5]

very interesting book about the possibility of speciation being driven by oxygen levels.

[Kadri · Rating 5 out of 5]

A very interesting and well written book