Given that we are nothing but mammals, it is perhaps understandable that humans are rather mammal-centric, something that conservation organisations capitalise on. But where palaeontology is concerned, dinosaurs get all the love. And that does early mammals little justice says Scottish palaeontologist and Palaeocast co-host Elsa Panciroli. Far from mere bit players cowering in the shadows of these “terrible lizards”, mammals have a long and rich evolutionary history that predates the dinosaurs but is poorly known outside of specialist circles. Panciroli’s debut changes all that and does so in a most readable and immersive fashion.
Beasts Before Us: The Untold Story of Mammal Origins and Evolution, written by Elsa Panciroli, published in Europe by Bloomsbury Publishing in June 2021 (hardback, 320 pages)
To pick up the tale of mammal evolution, Panciroli takes you all the way back to the Carboniferous (roughly 360–300 million years ago) when higher oxygen levels supported a land of giants. It was here that the first fish made landfall and tetrapods evolved. To get from this distant ancestor to modern mammals, you have to follow the story through groups whose names are likely unfamiliar. To help you visualise these, stylish illustrations from April Neander open each chapter, while the endpapers* provide a helpful family tree drawn by Marc Dando. These do not list all mentioned groups but do present the big picture and I found myself referring to them frequently.
Thus we get to meet the synapsids, one of which you will know: the sail-backed, no-it-is-not-a-dinosaur Dimetrodon. Synapsids included the pelycosaurs (also not dinosaurs), which gave rise to the therapsids: carnivores with more powerful jaws and a stronger bite. Some of these, including the gorgonopsians, pioneered sabre-teeth, proving later groups to be mere copy-cats. Convergent evolution is, quite literally, a recurrent theme that Panciroli mentions whenever she can get away with it. Various therapsids were also the first groups to evolve endothermy or warm-bloodedness, though “like so many of the features associated with mammals [it] emerged scattershot. It wasn’t switched on like a lightbulb, lighting up all therapsids at once” (p. 120).
As the end-Permian mass extinction wiped the slate clean, the age of reptiles had begun. But some of our mammal ancestors survived. Rising like a phoenix from the ashes were, amongst others, the dicynodonts, who would have looked you in the eye from behind tusks and a turtle-like beak. One particularly successful group, possibly because it dug burrows, was Lystrosaurus, a genus that in the early Triassic made up 90% of all vertebrates. A related group, the cynodonts, is largely responsible for the misconception that our ancestors were insignificant during the reign of the dinosaurs, as they evolved to be smaller. But this was a feature, not a bug: “With no space among the giants, they took a different route: they perfected being tiny” (p. 163). They exploited the safety of the night, became nocturnal, and developed sensitive eyes. They also lost some ribs and developed a waist, allowing for more flexibility in their locomotion—early synapsids had ribs all the way down.
“[One] group, the cynodonts, is largely responsible for the misconception that our ancestors were insignificant during the reign of the dinosaurs, as they evolved to be smaller. But this was a feature, not a bug”
The Jurassic saw groups such as tritylodontids, docodontans, and multituberculates flourish. As their names imply, these groups experimented with tooth morphology, which later became important diagnostic fossil characters. None of them left living descendants. Instead, it was the therians who were our direct ancestors, but they did not diversify until after the K–Pg boundary. Interestingly, Panciroli suggests** that it was not the dinosaurs that kept the therians in check, but competition from all the other Jurassic mammal groups. This more recent history of the adaptive radiation into modern marsupials and placental mammals is well known, so she purposefully ends the book where most others start the story of mammal evolution .
This brief exercise in name-dropping provides only a snapshot of what Panciroli discusses, and she does a far better job of it. She weaves in the history of fossil discovery and her own work at dig sites in South Africa and Scotland, or labwork at the European Synchrotron Radiation Facility in France. Next to telling the story of mammal evolution, Panciroli also takes on the task of disarming and deconstructing a large amount of cultural and linguistic baggage, with two issues standing out.
First, as part of a younger generation of scientists, Panciroli is keen to decolonise her discipline. This means acknowledging that the scientific collections on which she herself works are the spoils of empire. Our museums are filled with colonialist plunder. Especially in the first chapter, where she gives a potted history of geology and biology, she repeatedly points to the imperialist framework in which these disciplines were born and how that has shaped conventions and biases to this day. Celebrated figureheads such as Buckland, Darwin, Lyell, Cuvier, Hutton, Lamarck, Owen etc. simultaneously held ideas now considered unsavoury, and they rarely credited Indigenous knowledge or help in the acquisition of fossils. Furthermore, as a woman, she has a few things to say about diversity. Like many academic disciplines, palaeontology remains largely populated by white, Western men, and it has been hard to shake off the image of the “stereotypical male adventurer” and his “macho plundering of the past” (p. 249). Fortunately, the contributions of women are increasingly being acknowledged, and Panciroli here celebrates Polish Mesozoic mammal researcher Zofia Kielan-Jaworowska who was the first woman to lead fossil collection expeditions in Mongolia.
“[…] the long history of evolutionary theory means that outdated modes of thinking continue to permeate our language. […] Panciroli similarly uses every opportunity to remind you that evolution is not goal-directed”
Second, the long history of evolutionary theory means that outdated modes of thinking continue to permeate our language. She shudders at the term “mammal-like reptiles” still used to describe the synapsids: “This first amniote tetrapod was neither mammal nor reptile—neither of those groups had evolved yet” (p. 61). We did not evolve from reptiles, nor are they more primitive compared to us. Panciroli similarly uses every opportunity to remind you that evolution is not goal-directed: “It is random, the route forged by happenstance” (p. 57). It has proven hard to let go of the Scala Naturae, the idea of a linear series of improvements, “like an assembly-line through time” (p. 120) leading ultimately to the perfect organism: us.
This neatly leads to my last observation: Panciroli’s writing is sublime. Her prose is concise without being stunted, her visual metaphors rich without being flowery. Of the late Triassic mammals she writes: “These tiny ancestors were living microchips. They were night-vision goggles. They were fuzzy little ninjas, wielding shuriken teeth to reap their insect prey in silence and stealth” (p. 171). On the break-up of Pangaea: “After their epic 250 million-year snuggle, the continents of Earth were parting ways […] By the end of the Jurassic, the whole world was unzipping itself, with new seas and oceans splashing into the gaps” (p. 203). On the K–Pg event: “The universe drew an iridium line under things. From here on, life would be different” (p. 274). And her description of the tritylodontid herbivore niche is just beautiful: “All of the non-mammalian cynodonts had turned to dust, except for the tritylodontids […]. Natural selection had moulded them into premier leaf-grinding machines. Of course there had been synapsid herbivores before […] but those bulky predecessors were gone. In the world of crocs and dinosaurs, mammals had microscoped themselves into the understorey, and the tritylodontids were left to eat the scenery” (p. 237).
Beyond a few academic textbooks and technical monographs, the deep evolutionary history of mammals has remained largely hidden in the academic literature. Beasts Before Us unleashes their story most spectacularly and engagingly. This beautifully written debut marks Panciroli as a noteworthy new popular science author. May this be the first of many books! You might also want to check out my Q&A with Panciroli published over at the NHBS Conservation Hub.
* Illustrated endpapers are one of my favourite features in a book, and one that, I think, too few publishers and authors use.
** The paper arguing this, still in press when she wrote this book, has just been published in Current Biology.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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“The Story of the Earth in 25 Rocks: Tales of Important Geological Puzzles and the People Who Solved Them“, written by Donald R. Prothero, published by Columbia University Press in January 2018 (hardback, 354 pages)
The range of topics covered by Prothero is diverse, and seemingly not organised in any fashion. But start reading through the book, and connections are made across chapters. Some of his chapters tie in with Dartnell’s book Origins: How The Earth Made Us that I just reviewed, chronicling the discovery of economically important deposits of coal, tin or iron and how these were formed. Others will take the readers off the planet as he tackles meteorites and moon rocks. Interestingly, Prothero thinks Earth’s water has been present since the beginning, discounting the mechanism of delivery-by-comet, something which Starkey deemed a much more likely possibility (see my review of Catching Stardust: Comets, Asteroids and the Birth of the Solar System).
Throughout, Prothero highlights the role of chance discoveries, such as the finding of cyanobacterial colonies in Australia that leave behind domed rocky structures called stromatolites, some of the oldest trace fossils in the fossil record, or the famed iridium layer that birthed the idea of a cosmic impact ending the reign of the dinosaurs (see T. rex and the Crater of Doom – Prothero gives a very informative overview of how the tide of opinion and evidence on how impactful that impact was sways back and forth to this day). Another famous story is how Clair Patterson’s research on dating of meteorites produced exquisitely sensitive methods to measure lead levels, resulting in the discovery of widespread lead pollution, a discovery for which he was attacked by powerful industry lobbies throughout his lifetime.
“Prothero highlights the role of chance discoveries [such as] Clair Patterson’s research on dating of meteorites [that] produced exquisitely sensitive methods to measure lead levels, resulting in the discovery of widespread lead pollution […]”
Another theme that returns time and again is how external forces and priorities provided funding and resources for important discoveries. It was the search for coal in Victorian Britain that led William Smith to produce the first map of geological strata in England in 1815, which pretty much launched the discipline of stratigraphy (see The Map That Changed the World: A Tale of Rocks, Ruin and Redemption for more). Other authors have already highlighted how the military has been instrumental in the developing discipline of oceanography, providing the material and thirst for knowledge to map the globe’s deep sea.
Prothero rightfully lavishes most attention on the cornerstones of geology; concepts such as deep time (see e.g. Earth’s Deep History: How It Was Discovered and Why It Matters or Nature’s Clocks: How Scientists Measure the Age of Almost Everything) and plate tectonics. Other than the now-famous insights of Alfred Wegener (much ridiculed during his lifetime and afterwards, see my review of Four Revolutions in the Earth Sciences: From Heresy to Truth), he discusses all the evidence in favour, and the vindication that came with findings from amongst other palaeomagnetism (see my review of The Tectonic Plates are Moving! and The Spinning Magnet: The Force That Created the Modern World – and Could Destroy It). But he also highlights subsequent insights, such as subduction zones and transform faults (e.g. the infamous San Andreas Fault).
The Story of Earth in 25 Rocks celebrates the many scientists whose names and contributions have been downplayed, such as Marie Tharp’s contribution to creating a map of the entire ocean floor (see Soundings: The Story of the Remarkable Woman Who Mapped the Ocean Floor). Or the people who are rarely mentioned, such as Scotsman James Croll’s work on variation in Earth’s orbital motion patterns well before Milutin Milankovitch. Prothero rightfully speaks of the Croll-Milankovitch cycles. Similarly, his chapter on turbidites (the product of large underwater landslides) highlighted fascinating research and characters that were all new to me.
“The Story of Earth in 25 Rocks celebrates the many scientists […] who are rarely mentioned, such as Scotsman James Croll’s work on variation in Earth’s orbital motion patterns well before Milutin Milankovitch.”
Each chapter comes with a short recommended reading list, highlighting a selection of excellent popular science books and more academic works. A great selection of period photographs is included and many diagrams and graphs have been redrawn or slightly modified to ensure their legibility and usefulness – some photos of rock formations, on the other hand, would have been better off being reproduced in colour. There are some minor mistakes, such as submarine Alvin supposedly diving almost 4,800 kilometres beneath the waves (p. 19), which made me question the statement on page 146 that the Hull-Rust-Mahoning iron mine has produced over 650 million metric tonnes of ore, and more than 450 metric tonnes of waste (should that latter also be million metric tonnes, or is this mine particularly rich in iron ore?) Prothero furthermore reports dimensions and masses in both metric and imperial units in some chapters, but is not consistent in doing so throughout the book.
The above are but minor quibbles that take nothing away from the sheer joy and enthusiasm with which Prothero serves up these 25 chapters. Incredibly well written and insightful, there is something here for everyone with an interest in geology. Prothero distinguishes himself as an excellent science communicator and I cannot wait to get my hands on his other two books, The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution, which preceded this book, and The Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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“Origins: How The Earth Made Us“, written by Lewis Dartnell, published in Europe by The Bodley Head (a Vintage imprint) in January 2019 (hardback, 346 pages)
Dartnell takes as his starting point the evolution of Homo sapiens in East Africa. He subscribes to Maslin’s ideas for where and when we evolved, outlined in The Cradle of Humanity: How the Changing Landscape of Africa Made Us So Smart. The gist of his argument was that it was a combination of plate tectonics and climate. The geography of the African rift valley and pulses of climate variability interrupting longer periods of stability led to regional lakes rapidly appearing and disappearing. This unstable environment favoured adaptability and intelligence. Dartnell similarly gives a revealing geological explanation reaching back 55 million years for how the most recent ice age came about and how it has impacted human dispersal around the world.
Now, it is easy to accuse a popular science book like this of glossing over subtleties for the sake of a good story. I therefore appreciated that Dartnell clearly signposts there are frequent disagreements on the details of the story of human evolution, and that not all evidence points in the same direction: his narrative represents the consensus view. He is nuanced enough to point out what that may seem rapid and purposeful – humanity’s global migration starting 60,000 years ago – was, in fact, a matter of trial and error. I liked his suggestion that there may have been earlier attempts at migrating out of Africa, or developing agricultural civilizations, that simply fizzled out before taking off. Similarly, when he brings up the effects of the Toba eruption on early humans (see my review of When Humans Nearly Vanished: The Catastrophic Explosion of the Toba Volcano), he immediately flags this up as controversial. All this gave me a good feeling about the balance Dartnell is trying to strike between presenting a captivating narrative while sticking to the facts and how best to interpret them.
“there may have been earlier attempts at migrating out of Africa, or developing agricultural civilizations, that simply fizzled out before taking off.”
From this point forward, the remainder of the book deals with the last 10,000 years of human civilization, making excursions into deep time explanations where needed. For readers of Diamond’s Guns, Germs and Steel: A Short History of Everybody for the Last 13,000 Years this is perhaps more familiar territory as he discusses the rise of agriculture (see also my review of Against the Grain: A Deep History of the Earliest States for some nuanced counterpoints to the standard narrative) and livestock husbandry. Here he reaches back into deep time to explain why Eurasia ended up with so many more domesticable species compared to the Americas, and why the orientation of the continents made the spread of agriculture easy in Eurasia (which is oriented East-West), but hard in the Americas (which is oriented North-South).
With agriculture came trade and Dartnell chronicles the establishment of the first maritime and overland trade routes, leaning heavily on overview works such as The Sea and Civilization: A Maritime History of the World and The Silk Roads: A New History of the World. His interest is in how these were shaped by the geography of the seas (the shape of coastlines, the existence of naval bottlenecks) and the land (the ruggedness of the terrain, microclimates). And he explores how our subsequent maritime Age of Exploration, when Western nations started colonising countries around the globe, depended on, and was shaped by, the planetary patterns of ocean and air currents, in turn shaped by where plate tectonics has parked the continents currently.
In the same vein, he spends two chapters exploring the deep origin of the materials we use to build and construct with (whether architecture or objects and tools), how they are formed, how they have ended up distributed over the world the way they have, and how that has played into the fortunes of civilizations and nations. He talks of rocks and metals and does an excellent job explaining our current dependence on rare earth elements and platinum group metals.
“90% of the coal we have used since the Industrial Revolution was formed during the Carboniferous […] if that had not happened, would the Industrial Revolution have taken off?”
He is concerned about our continued appetite for these resources. His arguments got me thinking, and I wonder whether we might be reaching a hard limit. When our increasingly advanced machinery and electronics depend on almost all the elements in the periodic table, where do you go from there? These materials are – if not always rare – hard to obtain, and there are often no suitable replacements. When you depend on finite resources like that, and things like renewable energy technology and computers cannot function without, can we continue to science and engineer our way out of our problems? I get the feeling this is rarely thought or talked about when considering the future. Similarly, he convinces that transitions throughout our history have acted as a ratchet, allowing us to expand and increase our population to a point where there is no turning back (or at least not without drastically decreasing the size of our global population) – we would not be able to feed, clothe, and shelter this number of people anymore with yesterday’s technologies.
Finally, he gives a quick tour of energy (see also Energy and Civilization: A History) and how we transitioned from muscle power to wind and water power and then fossil fuels, taking the reader through the age of coal, the steam engine and then oil. Here, too, he is specifically interested in how these resources were formed and why they are found where they are found. From reviewing Energy: A Human History and Carboniferous Giants and Mass Extinction: The Late Paleozoic Ice Age World I was already familiar with the fact that 90% of the coal we have used since the Industrial Revolution was formed during the Carboniferous, some 360-300 million years ago (leading Dartnell to ask the same question as Rhodes in the former book: what if that had not happened, would the Industrial Revolution still have taken off?) But Dartnell provides a lucid geological explanation to the question why so much coal was formed then. And it turns out there was a similar period in which the vast majority of the world’s oil reserves were formed, again for a good geological reason.
In his book The Equations of Life: The Hidden Rules Shaping Evolution, Charles Cockell wrote that physics is life’s silent commander, setting hard limits on what evolution can and cannot do. I would argue that Dartnell here similarly convinces that geology is history’s silent commander. Very accessible and full of interesting ideas, Origins is a worthy contender in the saturated market of big history and environmental history books. Depending on how much you have read on this topic, not everything here will be novel, but I do think that with its deep time and geology perspectives, Dartnell goes a few steps beyond most books.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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“The Dinosaurs Rediscovered: How a Scientific Revolution is Rewriting History”, written by Michael J. Benton, published by Thames & Hudson in April 2019 (hardback, 320 pages)
If this sounds familiar, indeed, when I reviewed Steve Brusatte’s book The Rise and Fall of the Dinosaurs: The Untold Story of a Lost World, I praised the enviable ease with which he explained modern methodologies. Now, with all due respect to Brusatte (and I really, really enjoyed his book), Benton has almost 30 years on him. Next to having authored standard textbooks such as Vertebrate Palaeontology (currently in its fourth edition) and co-authored Introduction to Paleobiology and the Fossil Record (currently in its second edition), he is also the series editor for Wiley-Blackwell’s textbook series Topics in Paleobiology, and he has previously authored When Life Nearly Died: The Greatest Mass Extinction of All Time with Thames & Hudson, dealing with the end-Permian mass extinction. With a career spanning some four decades, if anyone can comment first-hand on the evolution of the field, it is Benton.
After a brief introduction on how scientific discoveries are made, and a short foray into the philosophy of science, the bulk of the book consists of nine chapters documenting areas where palaeontology has been revolutionised. Partially by new fossil finds, but, much more importantly, by new tools, new technologies, more powerful computers, lateral thinking, and interdisciplinary approaches.
Benton’s opening of the book is perhaps slightly risky, as he has put the most technical chapters first. There is the question of when the dinosaurs first evolved. After the giants of the Paleozoic went extinct (see my last review of Carboniferous Giants and Mass Extinction: The Late Paleozoic Ice Age World), did the dinosaurs opportunistically explode onto the scene, or did other reptile groups slowly fade with dinosaurs taking over the proverbial relay race? New computational tools have pushed the origin story further back in time, but have also shown that both explanations have something going for it.
“Ancient DNA may have revolutionised archaeology […], but Benton explains why we shouldn’t expect Jurassic Park to become reality anytime soon.”
Similarly, the picture of the dinosaur family tree benefited first from the cladistic revolution, which saw a different way of thinking about classifying species, collecting and analysing as many informative characters as possible to determine relationships. Then, with access to supercomputers, Benton and his team have been involved in producing an all-encompassing family tree, a so-called supertree (which you can explore in all its glory here), revealing how the dinosaur lineage diversified rapidly early on, but the rate of speciation slowed down after that. That things never stay still was shown only recently with Baron et al.‘s 2017 Nature paper that proposed some radical changes to the family tree (for an accessible take on it, see Darren Naish’s blog post at Scientific American).
If this is all a bit technical, despair not, the remainder of the book deals with more “mundane” questions your typical six-year-old might ask. Excavation techniques might have changed little since the dawn of the discipline, but imaging tools such as photogrammetry have revolutionised what palaeontologists can document at a dig site, while CT scanning offers a non-destructive technique afterwards to image what you have dug up. And new microscopy techniques, together with some fantastically preserved fossils, have revealed much about the colour of dinosaurs (and hey, feathers!).
“What really helps this book shine are the illustrations. Thames & Hudson […] has redrawn many of them specifically for this book.”
Ancient DNA may have revolutionised archaeology (see my review of Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past), but Benton explains why we shouldn’t expect Jurassic Park to become reality anytime soon. Nevertheless, even without dinosaurs stomping around here and now, we have learned so much about how they lived. Bone histology and X-ray imaging have revealed growth rates, while finite element analysis (a method borrowed from structural engineers who use it to stress-test designs of bridges and buildings on computers) has allowed calculations of bite forces and how dinosaurs ate, while analyses of microwear on tooth surfaces (see my reviews of The Tales Teeth Tell: Development, Evolution, Behavior and Evolution’s Bite: A Story of Teeth, Diet, and Human Origins) has shed light on their diet. Biomechanical computations and careful analyses of trackways tell us more about their posture, how they moved, whether they could run, and what the deal is with them flying, or at least flapping about.
And there is, of course, the always fascinating topic of their extinction. Benton has first-hand seen the rise and rise of the Alvarez asteroid impact hypothesis (see T. rex and the Crater of Doom and my review of The Ends of the World: Volcanic Apocalypses, Lethal Oceans and Our Quest to Understand Earth’s Past Mass Extinctions), despite the initial pushback from the uniformitarian crowd (see my review of Cataclysms: A New Geology for the Twenty-First Century), and he provides a great overview of why this idea has become so widely accepted. Even here, facts move quicker than book publishing can keep up, and the reveal (not two weeks ago!) of a site potentially recording the direct aftermath of the impact has raised eyebrows around the world (see DePalma et al.‘s PNAS paper and the accompanying article in The New Yorker). And it probably has more than one palaeontologist fervently hoping this is not an elaborate hoax. I am cautiously optimistic so far – this could be mindblowing, but let’s see more hard proof first.
“[Benton] convinces that now is a very exciting time, indeed, to be a palaeontologist. I can’t wait to see what surprises lie in store in the near future.”
In addition to Benton’s accessible writing, what helps this book shine are the illustrations. I regularly bemoan how few publishers get this right; complex figures are reproduced directly from their source in greyscale so you can’t tell apart the different lines and symbols in graphs, they are often too small, or the source material is so poor that resolution suffers or compression artefacts are visible. Not this book. Thames & Hudson is obviously known for their illustrated books, and checking the illustration credits suggests that their in-house art studio (?) has redrawn many of them specifically for this book. This in addition to two colour plate sections and some really nice species profiles. A job well done, and I wish more publishers went to this effort.
The Dinosaurs Rediscovered is easy to recommend. Benton’s enthusiasm is infectious, and his skill at packing so many exciting developments in this book speaks of his deep involvement in this field. He provides a fantastic overview of the revolutions in palaeontology over the last few decades and convinces that now is a very exciting time, indeed, to be a palaeontologist. I can’t wait to see what surprises lie in store in the near future.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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“The Tectonic Plates are Moving!“, written by Roy Livermore, published by Oxford University Press in April 2018 (hardback, 482 pages)
Livermore has divided this book into two parts, beginning with the first generation of scientists exposed to plate tectonics. I was surprised he didn’t start with Alfred Wegener, whose 1912 theory of continental drift is the intellectual progenitor of today’s plate tectonics (recognition for it evaded him during his lifetime, see the splendid biography Alfred Wegener: Science, Exploration, and the Theory of Continental Drift). Instead, Livermore starts in the 1960s with the discovery of the zebra-skin-like pattern of past magnetic polarity stored in spreading seabed (see my review of The Spinning Magnet: The Force That Created the Modern World – and Could Destroy It). The chain of events that led scientists to link this observation to others and suggest that the earth’s plates were moving, and the stubborn resistance by especially the US geological to this idea has been told elsewhere in brief (see Four Revolutions in the Earth Sciences: From Heresy to Truth) and at gruelling length (Frankel’s four-volume opus The Continental Drift Controversy), but Livermore here provides an excellent 180-page executive summary.
The real value of this book, however, lies in the second half, which takes the reader through all the subsequent developments in the 1980s and onwards. This part gives a wonderfully balanced overview of all sorts of controversies and new insights that complicated the picture developed so far. Plate tectonics turned out to not only destroy and create oceanic plates – continental crust could also be subducted and returned to the planet’s surface. Then there is continued disagreement over whether the supercontinent Pangaea that existed between approximately 320-175 million years ago was simply the latest iteration in a very long-term cycle of supercontinent formation and breakup. Nield popularised this idea in Supercontinent: 10 Billion Years in the Life of Our Planet, but it is not accepted by all geologists.
The US military makes repeated appearances in Livermore’s story, and geologists have often benefited from technologies developed during the Cold War when the military was trying to spot Russian submarines or listen out for tremors of nuclear explosions. Development of satellite technologies assisted in mapping the seabed, revealing the wonderfully complicated world of underwater subduction zones and mid-ocean ridges (see Searle’s Mid-Ocean Ridges for a technical lowdown).
“To paraphrase evolutionary biologist Theodosius Dobzhansky: nothing in geology makes sense except in the light of plate tectonics.”
Then there is the influence of plate tectonics on global climate through the long-term geochemical cycles described in The Oceans: A Deep History. Carbon dioxide is added to the atmosphere via volcanic eruptions and at spreading mid-ocean ridges (both obviously require plate tectonics). Removal of carbon dioxide happens when rocks erode over time. The chemical reactions involved turn carbon dioxide into various other compounds that are washed into seas by rivers. These compounds are used by marine organisms large and small to make their shells, which then end up buried in seafloor sediments when they die, and ultimately get recycled into the Earth’s interior when oceanic crust is subducted. How is that for a neat little long-term thermostat? Additionally, the continents waltzing around and the formation of land bridges (see my recent review of Land Bridges: Ancient Environments, Plant Migrations, and New World Connections) influence oceanic and atmospheric circulation, and thus climate, directly.
Finally, the current frontier of knowledge where all the action is: geophysics. What happens to the pieces of crust once they are subducted into the Earth’s interior? Do they descent all the way to the core to form evocatively called “slab graveyards”, from whence they rise up in the form of plumes as in a giant lava lamp? Or do they hover close under the planet’s surface in a separated convection layer? (A fiercely contested subject, see Plates vs Plumes: A Geological Controversy – Livermore sides with the idea of plumes). What of these mysterious entities at the boundary between the Earth’s core and the mantle called Tuzo and Jason? Torsvik & Cock described them in Earth History and Palaeogeography as plume generating zones responsible for the majority of the large volcanic eruptions linked to previous mass extinctions (see Brannen’s The Ends of the World: Volcanic Apocalypses, Lethal Oceans and Our Quest to Understand Earth’s Past Mass Extinctions, and see Ernst’s Large Igneous Provinces for the technical lowdown). Have they been fixed in place over deep time? Are there really only two of them? And what of interactions and heat exchange between the Earth’s molten core and the mantle? What does this mean for the Earth’s magnetic field? When did plate tectonics start? Has it gone through different phases?
Since we can drill and dig just a few kilometres into the Earth’s crust, the answers to all these questions are far out of our reach. It has only been in recent decades with the refinement of visualisation techniques such as seismic tomography and the development of complex computer models that we have been able to gather data and theorise on what happens in the Earth’s interior. I came away from this last section with a renewed respect for, and interest in, geophysics.
“What of these mysterious entities at the boundary between the Earth’s core and the mantle called Tuzo and Jason?”
So, what has plate tectonics ever done for us? From providing water to fill our oceans, hydrothermal vents where life probably first evolved, a carbon cycle to control long-term climate, to a geodynamo generating a magnetic field that prevents our protective atmosphere from being obliterated by the charged particles the sun hurls our way… plate tectonics has provided us with a planet that has been relatively stable for billions of years, providing just the right conditions for the evolution of complex life (see also The Goldilocks Planet: The Four Billion Year Story of Earth’s Climate). Having surveyed neighbouring planets, astrobiologists (they who study the possibility of life on other planets) have realised that plate tectonics will be a prerequisite for a habitable planet (for readable introductions, see How to Build a Habitable Planet: The Story of Earth from the Big Bang to Humankind and Lucky Planet: Why Earth is Exceptional – and What that Means for Life in the Universe).
The Tectonic Plates are Moving! is a rock-solid read (here, Livermore, have one of my puns): the pacing of the book is great, the irreverent jokes and anecdotes genuinely amusing, the overview of different schools of thought balanced, and the explanations lucid. Most of the jargon used is introduced and clarified, though I struggled a bit with all the names for rock and mineral types (there is no glossary included). I hope to remedy that with a basic geology textbook I have finally bought. There is a good number of helpful illustrations included, some of which would have been better had they been reproduced in a colour plate section.
Neither a dull textbook nor an overly technical read, Livermore strikes just the right balance and manages to deliver a compelling book on the importance of plate tectonics and the many exciting developments in past and current research.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
Other recommended books mentioned in this review:
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“Earth History and Palaeogeography“, written by Trond H. Torsvik and L. Robin M. Cocks published by Cambridge University Press in December 2016 (hardback, 317 pages)
Trond H. Torsvik and L. Robin M. Cocks, both established geologists, draw on a huge body of interdisciplinary knowledge for this book. This includes, amongst others, palaeomagnetism and polar reversals (see my recent review of The Spinning Magnet: The Force That Created the Modern World – and Could Destroy It for an introduction), past volcanic eruptions, geophysics and tomography (a technique to visualise the inside of the planet), the rock record, and fossil distribution. Putting this all together allows them to reconstruct the face of the Earth over the last 540 million years. We know that plate tectonics was happening earlier in time as well, the geological story at the heart of the lyrical A Wilder Time: Notes from a Geologist at the Edge of the Greenland Ice was that we have evidence for plate tectonics as far back as approximately 2 billion years, and this book even mentions 3 billion years. But details just become too sketchy to make reliable planetary-scale reconstructions. So, as the authors make clear, this is by no means the definitive story but a work in progress. This book shows the current state of our knowledge, which will no doubt be further refined in the future.
After outlining their methodology and introducing, with maps, all 268 tectonic units that they have recognised as currently making up the surface of our planet (that’s a lot more you typically see on schematic maps) we get to the bulk of the book. This consists of eleven chapters that cover each geological period from the Cambrian (541-487 million years ago) to the Neogene and Quaternary (23 million years ago to today). Each chapter starts with several overview maps of the whole planet at various stages of each geological period which are already worth their weight in gold if this floats your boat. But that’s just the beginning.
“[these] overview maps […] are already worth their weight in gold if this floats your boat.”
A large number of maps and diagrams show different projections and perspectives, systematically going through each of the major continents as they existed back then. These maps show current continent outlines and estimated coastlines and deep and shallow seas back then, but also divisions between plates where the seabed was spreading apart or where plates were being subducted or colliding to form mountains chains. Symbols indicate approximate locations of major reefs, ice caps, lakes, areas of volcanic activity including large igneous provinces (the massive volcanic eruptions implicated in mass extinctions that we met in The Ends of the World: Volcanic Apocalypses, Lethal Oceans and Our Quest to Understand Earth’s Past Mass Extinctions
), areas where coal was deposited, areas that dried up and left evaporites, faunal provinces that show the distribution of important fossil groups, as well as side-bars with approximate sea-level and climate conditions compared to today, and many other details. In the later chapters on geologically younger periods, when more details can be reliably reconstructed, many other diagrams and maps are shown, detailing the formation of mountain ranges such as the Himalayas, the appearance and disappearance of oceans, movements of the oceanic plates, etc. etc. The amount of information that is packed into these figures is breathtaking.
The text, meanwhile, links together the different events depicted and provides further context and details. Some things cannot be shown on the maps, such as the location of certain minor plates. We know they were somewhere, but we often lack enough information to place them on a map in any meaningful way. The text not only covers the geological details but also contains a section describing the dominant flora and fauna and important developments in the evolution of life during the period in question.
The book is not what you would call bedtime reading (though that did not stop me from doing so anyway) and is suffused with jargon. This comes from three sources. All geological periods are divided into shorter stages that have their own names, as shown on the official International Chronostratigraphic Chart that is printed on both endpapers. All 268 tectonic units have their own names that are introduced in detail in chapter 3. But on top of that is the terminology for geological processes and rock types. This is where my decision to study biology rather than geology comes back to bite me (I am looking at investing in some undergraduate geology textbooks because the subject continues to interest me). So if, like me, you can’t tell your ignimbrite from your gneiss, or don’t know the difference between volcanoclastic intercalations and diachronous migration, you might struggle with the text. Now, to fault the book for this would be completely missing the point. This is an advanced-level reference work, squarely aimed at an audience of geologists and palaeontologists with the relevant background knowledge – but it is good to know going in. Even so, with my limited knowledge of geological processes mostly gleaned from popular academic books, I was able to follow the grand narrative just fine. And what a fantastic story it tells!
“This […] advanced-level reference work [is] squarely aimed at an audience of geologists and palaeontologists with the relevant background knowledge”
I cannot think of another book that takes such a clear, graphic approach as Earth History and Palaeogeography does. Not being familiar with the field, I am hesitant to claim this is a first, but it is obviously a very valuable compilation of the current state of our knowledge. For geologists and palaeontologists this is a mandatory reference work, but academically-minded book readers might also find this very interesting. I expect I will regularly be pulling it off the shelf to consult it while reading other books on palaeontology or geology.
For those interested, there are supplementary online resources, including several programmes that allow you to make your own reconstructions, including graphics and maps like the ones shown in the book. I have not played around with this, but it is fantastic to see the authors willing to keep this project alive post-publication.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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“The Rise and Fall of the Dinosaurs: The Untold Story of a Lost World”, written by Steve Brusatte, published in Europe by Macmillan in April 2018 (hardback, 404 pages)
Brusatte has previously authored the textbook Dinosaur Paleobiology. The current book, however, is a pop-science account of these fascinating reptiles. Ordered roughly chronologically, it starts off with the Permian mass extinction some 252 million years ago. Brannen’s recent book The Ends of the World did a marvellous job introducing the five major mass extinctions, but Brusatte can be equally evocative in his descriptions. As in Martin’s The Evolution Underground, Brusatte advances the idea that underground burrows were crucial to survival.
Brusatte introduces the dinosauromorphs, the close evolutionary forebears of the dinosaurs. He talks us through the Triassic, when all the world was united in the supercontinent Pangaea, small dinosaurs competed with early mammal relatives, and the world was ruled by a reptilian sister group that would leave us the crocodiles. After the end-Triassic mass extinction, the dinosaurs were left standing and rose to dominance during the Jurassic and Cretaceous. We meet the sauropods, gigantic long-necked herbivores, and the various theropod carnivores that terrorised them. Two chapters introduce the tyrannosaurs and its most famous representative: Tyrannosaurus rex, which Hone details further in The Tyrannosaur Chronicles: The Biology of the Tyrant Dinosaurs.
And then there is the evolution of flight and the fantastic fossil discoveries of feathered dinosaurs in recent decades (some good entry-level books are Feathered Dinosaurs: The Origin of Birds or Flying Dinosaurs: How Fearsome Reptiles Became Birds). Brusatte ends with the Cretaceous mass extinction, Alvarez’s impact hypothesis, detailed in T. rex and the Crater of Doom, and the various lines of evidence leading up to it. The reign of the dinosaurs may be over, but Brusatte reminds us that some dinosaurs survived and are still with us today as birds, on which much more in The Ascent of Birds: How Modern Science is Revealing their Story.
“[…] Brusatte excels at making current scientific methods that have been crucial in the study of dinosaurs understandable”
Brusatte livens up the science with enthusiastic stories of discoveries in the field and the many talented palaeontologists he has worked with. Never too chatty of forcedly funny, these anecdotes are woven in skillfully and are relevant to the story at hand. Similarly, he introduces important historical figures such as, of course, Marsh and Cope, whose infamous rivalry known as the Bone Wars has been detailed in books such as The Bonehunters’ Revenge: Dinosaurs, Greed, and the Greatest Scientific Feud of the Gilded Age or The Gilded Dinosaur: The Fossil War Between ED Cope and OC Marsh and the Rise of American Science. But also Barnum Brown (the title of his biography, Barnum Brown: The Man Who Discovered Tyrannosaurus rex, explains his fame), or the eccentric Transylvanian Baron Franz Nopcsa von Felsö-Szilvás who offered a credible explanation for why Transylvanian dinosaurs were so small (see more about this phenomenon of dwarfism in Transylvanian Dinosaurs). Brusatte successfully brings these figures to life, shining a light on what palaeontology involved in decades gone by.
The thing that really makes this book stand out for me, though, is that Brusatte excels at making understandable current scientific methods that have been crucial in the study of dinosaurs. Whether it is radiometric dating, morphological disparity analysis, photogrammetry or finite element analysis, Brusatte casually but skillfully explains these methods with an ease that is enviable. So much so that he doesn’t even need to use illustrations to make himself clear. Instead, the book is illustrated with both period and contemporary black-and-white photos of fossils and the scientists who discovered them.
As befits a book of this scope, the production is rather lavish. The American version, published by William Morrow, has a really nice cover illustration by Todd Marshall. I was initially a bit disappointed by the more abstract illustration of Macmillan’s UK version, but the embossing of the drawing and the title gives it class. And Marshall’s drawings are still present opening each chapter.
The Rise and Fall of the Dinosaurs has received rave reviews, and it is easy to see why. The enthusiasm Brusatte has for his profession virtually drips off every page. I used this phrase before when reviewing Squid Empire, and it applies here: this book is fiendishly readable – I tore through it in just two evenings. Brusatte is a masterful storyteller who knows how to keep your attention, and the book is both wonderfully written and admirably accessible. Be warned though, you might just want to become a palaeontologist after reading it.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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“Squid Empire: The Rise and Fall of the Cephalopods”, written by Danna Staaf, published by ForeEdge, a University Press of New England imprint, in December 2017 (hardback, 237 pages)
Cephalopods have a long and illustrious evolutionary history, stretching back some 500 million years. The fact that they are still here means they have lived through their fair share of mass extinctions. After some basic morphology, Staaf quickly introduces us to the three groups on the family tree, as these are the main protagonists whose fate we will follow here.
A large chunk of the book deals with the now-extinct group of Ammonoids whose familiar whorled fossil remains are so numerous that they can be used to date rock strata. Although many species went extinct at the end of the Devonian, Permian and Triassic, some members of the lineage managed to survive, allowing the group to thrive, again and again, all the way until the end-Cretaceous. With Brannen’s recent The Ends of the World still fresh on my mind I was quite familiar with the details, but if you’re not, Staaf does an excellent job in giving a balanced picture of the various mass extinctions. She is equally capable of giving a short history of the Alvarez impact hypothesis, as she is able to explain anoxic events or large igneous provinces and flood basalts.
The second group are the slow-and-steady (evolutionarily speaking) Nautiloids who seem never to have diversified terribly much, but have kept on keeping on to this day. And, finally, there are the Coleoids who radiated to become today’s cuttlefish, squid and octopuses.
“[…] ongoing academic discussions are combined with Staaf’s narrative which is fiendishly readable”
And yes, I said octopuses rather than octopi. Staaf provides the best overview I have read so far of the whimsical discussion around how to pluralise this word. But far from mere whimsy, this book provides page upon page of fascinating insights. Whether it’s the intricacies of evolving buoyancy mechanisms allowing cephalopods to float, the way Coleoids internalised and in some groups virtually eliminated their shell, the continued confusion around the lower jaw or aptychus of the Ammonoids, or the arms race between cephalopods and their predators (first fish, then whales)… who knew there was so much fascinating research buried in the scientific literature?
Being a marine biologist herself, she is well-situated in these academic circles and has interviewed many scientists including Christian Klug, Dieter Korn, Kenneth de Baets, and Isabelle Kruta, all of whom are editors on the 2nd edition of the Ammonoid bible Ammonoid Paleobiology. Interesting findings and insider insights into ongoing academic discussions are combined with Staaf’s narrative which is fiendishly readable. In my opinion, her writing style strikes just the right balance between informative and understatedly entertaining (I sniggered throughout the book), without feeling forcedly funny. Admittedly, I have a soft spot for these squishy invertebrates, but I tore through this book in the space of a single seven-hour sitting! Squid Empire is a shining example of good use of illustrations supporting the text, especially the cephalopod family tree on page 46 is something you’ll be referring to time and again and has some clever details. Next to that, the book is also beautifully designed with stylised chapter headings and a beautiful Haeckel lithograph gracing the cover.
Dinosaurs may have time and again stolen the limelight, but Staaf shows an accessible book on the evolutionary history of cephalopods has been long overdue. With Squid Empire – which, can you believe it, is only her first book – she has established herself as cephalopod-champion par excellence. I know that 2018 has only just started, but already this book will be a strong contender as my book-of-the-year. This, ladies and gentlemen, is how you write a good popular academic book.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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“The Ends of the World: Volcanic Apocalypses, Lethal Oceans and Our Quest to Understand Earth’s Past Mass Extinctions”, written by Peter Brannen, published in Europe by Oneworld Publications in September 2017 (hardback, 330 pages)
Extinction and speciation happen, geologically speaking, continuously. You may have come across the term “background extinction rates”. But the geological record reveals there are episodes when species diversity, again geologically speaking, suddenly plunges, and a significant proportion of life forms disappear around the globe. If the concept of extinction didn’t really exist until Cuvier put it forward in 1796, the idea of sudden mass extinctions didn’t really catch on until Walter Alvarez and his team published their idea of death by comet in 1980 (Elizabeth Kolbert gives an excellent overview of the intellectual history in The Sixth Extinction).
The Ends of the World is science journalist Peter Brannen’s first foray into book writing. He has set himself the ambitious target to give an overview of what we currently know of the Big Five mass extinctions (end-Ordovician, Devonian, Permian, Triassic, and Cretaceous respectively) by interviewing scores of scientists.
In nimble prose that is readable and amusing (I found myself sniggering throughout the book) he walks us through them chronologically, starting off with the oldest. Without repeating the many fascinating details and ideas covered, the consensus is that if there is one thing that all these events have in common, it is that there never is just a single cause. All of these events are characterised by an extraordinary set of circumstances coming together to create some truly challenging conditions for life on earth. And, despite the popular notion of asteroid impacts, most often the threat has come from within. Twice in the form of ice and anoxic (i.e. oxygen-starved) seas at the ends of the understudied Ordovician (445 million years ago, or mya for short) and Devonian (two extinction pulses at 374 and 359 mya), together with a raft of other circumstances. Twice in the form of volcanism-induced global warming with accompanying misery at the end of the Permian (252 mya) and Triassic (201 mya). And then, of course, the asteroid impact at the end of the Cretaceous (65 mya).
Brannen does an excellent job giving airtime to different viewpoints and theories, because the above summary is very brief, and the science isn’t all settled on this. Even the by now widely accepted asteroid impact hypothesis is more complicated than that. When Walter Alvarez and his team put their theory forward in their 1980 Science paper, it was initially met with disbelief and scepticism. And healthy scientific scepticism is good. It has forced the scientific community to gather more data to see if this idea could be supported. By now enough supporting evidence is available and, after being known to the wrong people for over a decade (geophysicists working for an oil company), we have located the site of impact around the Mexican peninsula of Yucatán (this story is also chronicled in Alvarez’s book T. rex and the Crater of Doom). But other, similarly massive impacts have not caused any mass die-offs, giving more credence to the ideas of a few vocal critics who think earthquakes in the impact’s wake ramped up episodes of ongoing volcanism.
“[…] to be a geologist means changing your perception of time.”
If there is anything that ought to be highlighted in Brannen’s writing, it is how he manages to convey the absolute vastness of the time scales we are dealing with. Consider that all of recorded human history, all the thousands of years, have taken place in the most recent interglacial period, which is only one of twenty such balmy 10,000-year intervals in the earth’s most recent 2.6 million year ice age, and you will come to understand that to be a geologist means changing your perception of time.
The other thing Brannen does exceedingly well is to evoke the sheer scale of the destruction that has been wrought in the distant past. If you thought the 2013 Chelyabinsk meteorite was frightening, buckle up for the end-Cretaceous impactor. Similarly, the volcanism that wiped out some 95% of all life-forms at the end-Permian, making it the single most destructive event in the history of life, is hard to fathom. Forget the picturesque volcanoes that you know: continental flood basalts are literally the earth puking out its guts and covering whole continents with lava that gets stacked up miles high. As we have never witnessed these rare events, they defy comprehension.
Having discussed the Big Five, Brannen is not quite done yet. This book would not be complete if he not also touched upon the current ongoing loss of biodiversity. There is an eerie correlation between our ancestors arriving in new regions and megafauna disappearing. The overkill hypothesis, put forward by Paul S. Martin (also see his book Twilight of the Mammoths), has not been well received by politically correct anthropologists and social scientists, but I see no problem with it. Brannen speaks to British geologist Hallam who thinks it’s high time we get rid of this romanticized notion of the wild savage living in harmony with nature. I couldn’t agree more. [Edit: having now reviewed End of the Megafauna: The Fate of the World’s Hugest, Fiercest, and Strangest Animals, I have changed my mind on this somewhat.]
“The tempo with which we are burning fossil fuels like there is no tomorrow […] is comparable to the episodes of large-scale volcanism of the past. Deep history teaches us how the planet’s climate will react.”
Even so, it’s interesting to read that many of the palaeontologists in this book don’t consider this the sixth extinction. Yet. They all agree that we are inflicting tremendous damage to our environment and have caused the extinction of many species. And the fact that we are exerting multiple pressures (climate change AND overhunting/fishing AND habitat fragmentation etc.) means we could pass a tipping point somewhere along the line. But the current losses pale in comparison with the truly staggering losses incurred during previous mass extinctions. Many palaeontologists think it’s way too early, and overly dramatic, to already talk about a sixth mass extinction, as much as it makes for juicy headlines. In the long run, this may make for no more than a blip in the geological record.
Throughout the book, Brannen skilfully highlights the relevance of studying Earth’s deep history to the here and now. The tempo with which we are burning fossil fuels like there is no tomorrow, and releasing greenhouse gases into the atmosphere is comparable to the episodes of large-scale volcanism of the past. Deep history teaches us how the planet’s climate will react. The geochemistry is simple and uncontested, and our planet has been here many times before. Natural geochemical cycles can mop up this excess, but these cycles play out on time scales of hundreds of thousands of years. As some scientists point out here, it is far more likely that our civilization will buckle under the strain of overpopulation, failing agricultural systems and climate refugees well before we can release comparable amounts of greenhouse gases, as even a few degrees of warming will drastically change the world in which we live.
What could have been a book of doom and gloom has become a phenomenally good read in the hands of Brannen. His writing is witty and irreverent in places and had me both amused and intrigued throughout. His balanced coverage of this massive topic is excellent, giving voice to the many opinions and ideas currently circulating. If you want an up-to-date picture of what we know, this is the best place to start in my opinion.
Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.
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