After three previous books in this format on fossils, rocks, and dinosaurs, geologist and palaeontologist Donald R. Prothero here tackles the story of evolution in 25 notable discoveries. More so than the previous trio, this book tries to be a servant to two masters, resulting in a mixed bag.

The Story of Evolution in 25 Discoveries: The Evidence and the People Who Found It, written by Donald R. Prothero, published by Columbia University Press in December 2020 (hardback, 360 pages)

Prothero has organised The Story of Evolution in 25 Discoveries in a logical fashion. After convincing the reader that the universe and our planet are, indeed, really old, he considers some of Darwin’s lines of evidence for evolution, followed by several great transitions in evolution as revealed by the fossil record, more recent evidence from genetics and molecular biology, and, of course, evidence for the evolution of humans.

As in his previous books, Prothero manages to dig up some remarkable stories. For example, Darwin initially mistook the finches on the Galápagos for wrens, blackbirds, and other species. Only when he handed them to the famous ornithologist John Gould for a second opinion did it become clear that these were all finch species adapted to local conditions on the different islands. It later fell to others such as Peter and Rosemary Grant to do the long-term studies that elevated them to the icon of evolution they have become. Meanwhile, Othniel Charles Marsh’s monograph on primitive birds that still had teeth was unexpectedly branded a waste of taxpayer’s money when US congress was looking for excuses to cut funding to the US Geological Survey in the 1890s.

In many places, Prothero is careful and balanced in his coverage. He highlights the contribution of the historically overlooked Alfred Russel Wallace who independently hit on the idea of natural selection after Darwin had already been labouring on it for decades. And while Ernst Haeckel was accused of fraud over his famous drawings showing the embryonic development of different vertebrates, Prothero explains how there is a kernel of truth to Haeckel’s claim that ontogeny recapitulates phylogeny, even if “he may have been a bit overzealous in his drawings” (p. 69). On Jean-Baptiste de Lamarck and his ideas, Prothero clarifies how there was much more to him than the caricature of the “guy who got evolution wrong” (p. 198) that he became.

“In many places, Prothero is careful and balanced in his coverage […] he clarifies how there was much more to Jean-Baptiste de Lamarck […] than the caricature of the “guy who got evolution wrong””

There are classic topics such as convergent evolution, the evolution of the eye, and Lynn Margulis and her theory of endosymbiosis. The relatively young branch of evolutionary developmental biology and the discovery of Hox genes showed that, actually, yes, nature does make leaps and does not always result in slow and gradual changes. Throughout, Prothero repeatedly reminds you that the evolutionary relationships between organisms are like a bush, and not a linear progression from primitive to more advanced creatures. He explains that evolution does not always result in perfect adaptations—they only have to be good enough to help in producing the next generation. And he points out that natural selection can only ever work with the material at hand, resulting in many jury-rigged contrivances, including in humans.

Now, Prothero is also a noted sceptic. A good deal of this book has the secondary aim of showing that creationism is an utterly flawed idea and that the evidence for evolution reveals no traces of intelligent design whatsoever. The thing is, he already did this exercise in Evolution: What the Fossils Say and Why It Matters, so does it need repeating? He spends no fewer than seven chapters here on examples of transitional fossils that provide a detailed picture of fish leaving the water, whales returning to it, birds evolving from dinosaurs, giraffes evolving longer necks and elephants longer trunks, horses losing their toes and snakes their legs, and turtles acquiring shells. You almost get the feeling that he just cannot help himself.

I have few gripes with the topics that Prothero chose to include here, but I felt somewhat disappointed by all the topics he left out as a consequence of this secondary mission. Two notable omissions are the process of domestication, even though Darwin used numerous examples of it in On the Origin of Species and then wrote a separate book about it. The same is true for Darwin’s other big idea: there is no mention of sexual selection, sperm competition, or mate choice.

“[…] this book has the secondary aim of showing that creationism is an utterly flawed idea […] but I felt somewhat disappointed by all the topics he left out as a consequence […]”

Beyond these, there is little on speciation and biodiversity, the formation of higher taxa, or the difficulty with species concepts. Epigenetics is mentioned, but not by name. The textbook example of the peppered moth is included, but there is no further discussion on camouflage, mimicry, or warning signals. Richard Dawkins has to make do with two brief mentions, but there is nothing about the different levels of selection, whether selfish genes or group selection. And I am sure Prothero could have beautifully explained the difference between the modern and extended syntheses.

The focus on convincing the reader of the evidence against design raises the question of who this book is written for. For evolutionary biologists like myself, Prothero is preaching to the choir, while creationists are unlikely to pick this book up. The best this might achieve is to remind biologists of the evidence for evolution if we ever find ourselves debating creationists.

Prothero is a fantastic science communicator, and I really enjoy this format of 25 vignettes by which to examine the many facets of a topic. The material that he did choose to include is written with verve and balance. In my opinion, however, the dual motive underlying The Story of Evolution in 25 Discoveries means that he left out many relevant topics and has written a book of narrower focus than the title might suggest.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

The Story of Evolution in 25 Discoveries

Other recommended books mentioned in this review:

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Peter Godfrey-Smith is popularly known as the scuba-diving philosopher and has just published his new book Metazoa, in which he plumbs the evolutionary origins of minds. In preparation for reviewing that book, I am (finally) turning my attention to his initial 2016 bestseller Other Minds. Here he beholds the octopus, only to find that, behind those eight tentacles, an intelligence quite unlike ours beholds him in turn.

Other Minds: The Octopus and the Evolution of Intelligent Life, written by Peter Godfrey-Smith, published in Europe by William Collins (a HarperCollins imprint) in March 2018 (paperback, 263 pages)

It is hard not to be familiar with at least anecdotal evidence that octopuses are unusually smart and inventive creatures. Stories from aquarium owners and results from behavioural experiments make for popular fodder in (science) news outlets. Sy Montgomery’s incredibly touching The Soul of an Octopus, which I read some years ago, only added to this impression. And lacking a true case of “first contact”, Russel Powell mentioned in Contingency and Convergence that coleoid cephalopod mollusks “are rightfully considered intelligent aliens on Earth” (his p. 140). But if like me, you have not read up on the more technical literature on their behaviour and cognition, it is hard to really fathom the octopus.

To make the reader appreciate just how different their intelligence is, Godfrey-Smith therefore first takes the reader down the evolutionary tree of life, back to our last common ancestor some 600 million years ago. Before the explosions of body plans in the Cambrian, the Ediacaran fauna consisted mostly of mats of bacteria and algae grazed by crawling invertebrates—a seemingly tranquil tableau dubbed the Garden of Ediacara by one author. The likely sequence of events that led, quite literally, to the rise of the cephalopods involved the development of buoyant shells, the invention of jet propulsion, and, in some groups, the almost complete loss of the protective shell.

“[…] how [do] octopuses experience the world given their hybrid centralised-decentralised nervous system?”

Godfrey-Smith only touches on those stages of cephalopod evolution that are relevant to his story here, which allowed Danna Staaf in 2017 to complete that picture with her magnificent book Squid Empire. What he is interested in is what the development of such utterly flexible bodies meant for brain development. First off, octopus brains are quite unlikely any others: their oesophagus runs through a ring-shaped central brain (with attendant risks when swallowing spiky prey), while their arms all contain large numbers of neurons. It seems that, at least part of the time, the arms “enjoy considerable independence” and “seem “curiously divorced” from the brain” (p. 67), suggesting a mix of top-down control by the central brain and a certain neural autonomy in each arm.

What lifts Other Minds above mere slack-jawed voyeurism at nature’s weirdness typical of fluffy pop-science books is that Godfrey-Smith, as a philosopher, is both interested and capable of exploring this far deeper. Yet, he does this with a style that, for want of a better description, feels kind and caring. So, when on page 24 he talks of the sensory-motor view of nervous systems, he bothers with a polite footnote: “If you’ve seen the word “sensorimotor” instead, please treat this as the same“. Thus, when he introduces the psychological concept of embodied cognition, you can rest assured that, as a reader, you will not be left feeling out of your depth. This refers to the notion that some of our smartness is encoded in our body rather than our brain. The constraints imposed by the joints and angles of our limbs make walking a rather natural solution to the problem of moving around. But how does this work for an octopus, whose body has no fixed shape? Their embodiment is different, to say the least, but Godfrey-Smith takes it a step further, arguing that “The octopus lives outside the usual body/brain divide” (p. 76).

These and other observations lead to the question of what it feels like to be an octopus. This is where Other Minds dives deeper, pondering the evolution and nature of consciousness and experience, and how octopuses experience the world given their hybrid centralised-decentralised nervous system. He takes a particularly close look at the fantastic colour-changing capabilities of cuttlefish, the most expressive of the cephalopods. This is all the more surprising given that they are effectively colour-blind, as they possess only one kind of photoreceptor (versus three in humans). Part of the answer to this puzzle was revealed by recent research on a different octopus species that showed that light-sensitive molecules in its skin allow it to both sense light (yes, with its skin) and respond with colour changes.

“[…] what Godfrey-Smith has been doing here, chapter by chapter, is gently blowing your mind.”

The theoretical and philosophical ponderings here are pleasantly lightened up with anecdotes from Godfrey-Smith’s observations on wild octopuses while scuba-diving at an underwater site in Australia dubbed Octopolis. Due to its high density of octopuses, this is a particularly interesting and rare study site in itself, as he reveals here.

All of the observations and studies mentioned here make for an even more bizarre picture once you realise that most octopus species live only a few years, with females breeding once and then dying. Why such neuronal profligacy? A quick tour into the evolution of senescence leads Godfrey-Smith to a neat explanation that takes on board the peculiarities of their evolutionary history. Here is an organism in which the loss of its shell led to the unusual combination of a complex nervous system to control a body of unbounded possibility, with a life-fast–die-young approach to reproduction due to an increased vulnerability to predation.

So I ask you again, what is it like to be an octopus? Once you reconsider this question towards the end of the book, you will realise that what Godfrey-Smith has been doing here, chapter by chapter, is gently blowing your mind. The subject matter is fascinating in itself, but it is his light touch and deft handling of complex and sometimes abstract concepts that make it easy to see why Other Minds was such a runaway success. Can he pull this off again and continue to captivate his audience? I will turn to his new book Metazoa next to find out just that.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Other Minds

Other recommended books mentioned in this review:

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Some time after I reviewed Angela Saini’s book Superior, I was contacted by medical anthropologist and science writer Alondra Oubré, offering me the opportunity to review her new book. The overall aim of Science in Black and White might be the same—the debunking of the biological arguments used to justify racist thinking—but Oubré shows there is more than one approach to get there.

Science in Black and White: How Biology and Environment Shape Our Racial Divide, written by Alondra Oubré, published by Prometheus Books in April 2020 (hardback, 376 pages)

Scientific racism has a long history, so the first third of this book provides plenty of background information and history to get you oriented. This includes the origins of the nature vs. nurture debate, social Darwinism, and eugenics. The rise and fall of the blank slate, the notion that the human mind is shaped solely by the environment. The rise of both behavioural genetics, which studies genes associated with behaviour, and Darwinian medicine, which looks at evolutionary explanations for why some genetically related groups are more prone to certain diseases. The basics of natural selection, DNA, SNPs (single-nucleotide polymorphisms—the single-base-pair mutations that much research has focused on), and the method of genome-wide association studies that allow you to rapidly compare whole genomes for numerous such mutations. But also the concepts of gene × environment interactions, epigenetics (inheritance through other mechanisms than DNA), and biological plasticity. And, finally, a primer on brain architecture.

In case you were in doubt, Science in Black and White is an information-dense and intensely data-driven book that is meticulously annotated. Hundreds of endnotes reference the studies that Oubré draws on to back up her statements and claims. In discussing this background, she already reveals a long history of trying to justify exploitation, colonialism, and white supremacy with scientific arguments. Most of that has now been shown for what it is: flawed research, full of confirmation biases and faulty assumptions. And yet, there remain plenty of right-wing scholars happy to use the latest research tools to push their agenda, while others continue to misinterpret new results.

The remaining two-thirds of the book thus samples a wide range of modern research and what it is and is not telling. This covers purported ethnic differences in IQ, the use of MRI to show racial differences in brain features and anatomy, and the use of candidate gene association studies that result in those headline-grabbing claims of “scientists have found gene for X!”. But Oubré also covers studies on sexual maturation and age of puberty onset, with the accompanying claims that African American girls start earlier—the not-so-subtle hint being that this makes them more prone to adolescent behavioural problems, teenage pregnancies etc. And there is the tale of testosterone and now the AR or androgen receptor gene, with some scholars seeking to pin increased violence and incarceration rates of African Americans on hormones.

“By the end of the book, it is hard not to feel that some people are just incorrigible racists, hell-bent on proving some link, any link, to support their notion of black inferiority and white supremacy.”

These chapters offer plenty of asides that might not immediately deal with racial science, but that serve to place it in a wider context and explain technical details. Nevertheless, a clear pattern emerges. In chapter after chapter, Oubré shows how simplistic claims of racial differences in behaviour or personality traits that are pinned on genetics do not stand up to scrutiny. Further research invariably shows that things are, well, complicated. By the end of the book, it is hard not to feel that some people are just incorrigible racists, hell-bent on proving some link, any link, to support their notion of black inferiority and white supremacy.

To expound on this a bit more, pro-nature advocates love to flaunt statistically significant results, but they rarely discuss the extent of variation around averages. Nor do they consider effect sizes, i.e. are minuscule but statistically significant differences actually biologically or socially relevant? And the correlations they show do not equal causation, though this is frequently overlooked or conveniently forgotten. Their claims are thus already on shaky ground by themselves.

What complicates such attempts at straightforward genetic explanations further are environmental influences, which can completely overrule genetic tendencies, and epigenetics, which add another layer of complexity. Some examples discussed here include brain structure (powerfully shaped by nutrition and early childhood development), intelligence (influenced e.g. by the socioeconomic status of the family you grew up in, but also by epigenetics, e.g. the chemical substance DNA methyltransferase that can tweak the activity of genes associated with intelligence), or the effect of genes on aggressive behaviour (which can be completely annulled by growing up in nurturing environments free of abuse). Furthermore, the genetic basis of many traits is complex, influenced by thousands of genes with tiny contributions each (so-called polygenic traits—Robert Plomin makes a notable appearance here).

“This book is not driven by a pro-nurture agenda; Oubré repeatedly hammers home the message that nature vs. nurture ought to be replaced by nature plus nurture. Both play a role.”

Intelligence has been a hot and recurrent topic over the decades in this kind of research, and one oddity struck me: Oubré takes as a given the reality of the IQ gap, the idea that white people are smarter than black people because they score higher on intelligence tests. I might be mistaken, but I was under the impression that this gap is subjective, notably because IQ tests are notorious for their inbuilt (cultural) biases and are thus of questionable value.

Aside from that, I found Oubré’s dispassionate approach a breath of fresh air. I greatly appreciated her neutral post-mortem of the Samuel Morton–Stephen Jay Gould debacle on braincase volume and its link to intelligence*. Where racialist scholars have a point, Oubré will readily grant them it. And while for Saini all research on ethnic differences is suspect by definition, Oubré is level-headed, highlighting its value in understanding why ethnic groups differ in their vulnerability to certain diseases (e.g. the increased risk of prostate cancer in African American men). This book is not driven by a pro-nurture agenda; Oubré repeatedly hammers home the message that nature vs. nurture ought to be replaced by nature plus nurture. Both play a role. Her epilogue, which highlights that clan or family genetics might offer a new perspective is remarkable in that sense.

Science in Black and White is not necessarily the easiest book to read and I can see people getting bogged down by the rich technical detail provided here. But if you want to engage with the nitty-gritty and go deeper into the claims of racialist scholars and understand why they are mistaken, this book is the ticket.

* Gould shot down Morton’s ideas in his book The Mismeasure of Man, but later, more careful reanalysis found that Gould’s approach was not free of confirmation bias either, causing no end of glee in certain quarters.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Science in Black and White

Other recommended books mentioned in this review:

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“Superior: The Return of Race Science”, written by Angela Saini, published in Europe by 4th Estate in May 2019 (hardback, 272 pages)

The title Superior is a bit of a play on Saini’s very successful previous book, Inferior: The True Power of Women and the Science That Shows it. Just to make sure that there can be no misunderstanding the book’s angle, a quote from Reni Eddo-Lodge, author of Why I’m No Longer Talking to White People About Race, graces the dustjacket: this book roundly debunks attempts to give racism scientific underpinnings.

The prologue and first introductory chapter already make some very sharp observations: “We can draw lines across the world any way we choose, and in the history of race science, people have” (p. 5). Or the fact that Enlightenment thinkers, at the dawn of what we consider modern science, took the politics of their day as a starting point. At a time when slavery and exploitation by white Europeans were part and parcel of everyday life, researchers did not start off free of prejudice or bias.

These observations lead to the bulk of the book; through numerous interviews Saini provides a well written and fascinating overview of how science got tangled into the story of race and how old biases persist, some subtly, some decidedly less so. Darwin’s theory of evolution and his idea that we had a common ancestor put to bed the idea that what were called human races emerged separately, a predominant idea used to justify colonialism and slavery back then. But it did not stop racist thought and was bankrolled into it.

“The chapters where [Saini] charts what happened to race science post-WWII […] shows [her] at her most probing, leaving no difficult or thorny topic untouched.”

Saini chronicles the rise of eugenics, which is the idea to use our understanding of genetics to breed better humans the way you would breed livestock (some of this already came up in my reviews of She Has Her Mother’s Laugh: The Powers, Perversions, and Potential of Heredity and Genetics in the Madhouse: The Unknown History of Human Heredity). These ideas fed into the atrocities committed during World War II, and Saini chillingly reminds the reader that prominent scientists and well-respected intellectuals of their day got drawn into this.

Really eye-opening were the chapters where she charts what happened to race science post-WWII. Richard Lewontin’s landmark 1972 paper showed that variation in genetic diversity within old-fashioned racial categories was far larger than between these categories, vindicating earlier opinions that these categories had no biological basis (see also Not in Our Genes: Biology, Ideology, and Human Nature). But while the mainstream was busy accepting this, race science just went underground, as shown by Saini’s account of the academic right-wing fringe journal Mankind Quarterly and funding for this kind of research by the Pioneer Fund (see Sussman’s The Myth of Race: The Troubling Persistence of an Unscientific Idea for more). And lately scientific racism is on the rise again, with a new generation of people ready to misappropriate science for their own political agendas.

This part shows Saini at her most probing, leaving no difficult or thorny topic untouched, such as the continued use of racial categories when prescribing drugs against hypertension. Or the failed attempts to find racial difference in intelligence by looking at IQ scores, itself a very fraught concept. Her contention that race is a social construct used to justify political power play is supported by numerous sharp observations – so many I started to run out of my stack of post-it notes that I normally use to mark up noteworthy passages. I was totally on board with this part of her book and found it powerful and convincing.

“[The] contention that race is a social construct used to justify political power play is supported by numerous sharp observations”

Yet I have some criticism, and there is a certain incongruity at play here. Racial categories may have no biological basis, but there is genetic variation within and between human populations. To be crystal clear, I do not think these offer any justification for racism, but labelling this fact racist is also missing the point. And Saini seems very ill at ease with these findings.

So, on the one hand she includes geneticist Mark Jobling explaining the founder effect; the loss of genetic variation when small groups of individuals establish new populations, as happened during human migrations 100,000–50,000 years ago. And she remarks how India’s caste system with its restrictions on marriage has left a mark on the genetic makeup of castes, as shown by the incidence of rare genetic disorders.

But then on the other hand, she labels population genetics, which studies such variation to, for example, learn more about human evolution, as a rebranding of race science for the 21st century. The pioneering work in this field by Luigi Luca Cavalli-Sforza (see his Genes, People and Languages), who was about as outspokenly anti-racist as one could be, is eyed suspiciously. David Reich’s work on ancient DNA (DNA retrieved from archaeological remains) has shown humanity’s history to be one of a constant churn of groups migrating, interbreeding and displacing each other (see my review of his excellent Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past). But his suggestion that there are real genetic differences (“not large, but not non-existent either”) between e.g. West Africans and Europeans after evolving in separation for 70,000 years seems to scandalize her: “They are words I never expected to hear from a mainstream, respected geneticist” (p. 182).

“She labels population genetics, which studies human genetic variation to, for example, learn more about human evolution, as a rebranding of race science for the 21st century.”

Of course, she writes repeatedly, Cavalli-Sforza and Reich are not racists and their intentions are good, but their research could be misappropriated. The idea that it could help demolish the very racial prejudices she is fighting unfortunately does not seem to have much currency with her. In my opinion, in her fervour, she unfairly casts a shadow on the research and reputation of these scholars. I think it is a pity that Saini leaves unexamined the question of how best to interpret these findings and prevent them from being misappropriated, instead conflating them with the larger target she is aiming for: debunking race science.

That criticism notwithstanding, there are many strong points in this book. Her probing questions lay bare the often implicit biases many of us still retain. Her own background and experiences bring a much-needed perspective to this subject – one that I would much rather read than that of, say, a white male scientist. And the book is an engrossing read that did not let me go. All this makes Superior a potent condemnation of race science and all its fallacies, even if I did not agree with her categorizing population genetics as such.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Superior paperback, hardback, ebook, audiobook or audio CD

Other recommended books mentioned in this review:

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