“Evolutions: Fifteen Myths That Explain Our World“, written by Oren Harman, published in Europe by Head of Zeus in November 2018 (hardback, 242 pages)

Before I heap praise on this book, allow me a short whinge, for I was not quite sure what to make of the book’s brief. “For all its astounding achievements, has science provided protection from jealousy or love?” asks the dust jacket. This smacks of a caricature – what kind of a question is that? In his introduction, Harman mentions how we worship atheist horsemen, i.e. the likes of Dawkins (see The Four Horsemen: The Discussion that Sparked an Atheist Revolution). But they are a vocal minority – plenty of moderate voices warn of the dangers of scientism (see my review of Science Unlimited? The Challenges of Scientism). Others will affirm that whole fields of enquiry such as morality simply fall outside of the remit of scientific endeavour. To ask the above question and expect science to provide a sensible answer is, in my opinion, to misunderstand its limitations. I think you will find very few scientists, not even these horsemen, willing to argue that science negates more subjective experiences such as storytelling, music, art, or the human craving for these.

But enough already. Harman quoting Hubble as saying that: “the scientist explains the world by successive approximations”, and describing science as “the most honest attempt of our age to explain our greatest mysteries” makes it clear we are on the same page. Driven by a childhood fascination with Greek myths, Harman here uses the narrative structure of the epic poem to tell of our current scientific understanding of the history of life. A sort of “evolution’s greatest hits”, if you will, not unlike Nick Lane’s Life Ascending: The Ten Great Inventions of Evolution or Matt Wilkinson’s Restless Creatures: The Story of Life in Ten Movements.

Thus, the opening chapter Fate, chronicling the birth of the universe, dark energy, string theory, and the idea of the multiverse, ponders and concludes that our universe is

“just one of infinite possibilities, necessary to no one but us“.

The hypothesis that Earth’s moon formed following a huge impact (see The Big Splat: Or How Our Moon Came to Be) becomes a parable for motherhood and the inexorable loss that comes as children grow up. The moon’s slow drift away from our planet

“not a child’s rebellion. But then again maybe it is your dark side, opaque to me. I am too young to know, and too old to find out.“

The chapter on love portrays our thinking on the origin of life, the idea of an RNA world and ribozymes (see Life from an RNA World: The Ancestor within) where

“lovers were those who exchanged genetic materials […] there were no scorned lovers, only lovers who had never met“.

Similarly, the rise of DNA changed the world order:

“With permission from Chemistry, the zippered potentate seized control of heredity.”

The rise of multicellularity and sex gave new meaning to Death, introducing

“a two-tier economy: like the flesh surrounding the seeds of fruit, bodies became shells, protecting the gametes. And when the seeds are planted the fruits can rot.“

An embittered trilobite speaks to us of the evolution of the eye and the Cambrian Explosion (see Andrew Parker’s argument in In the Blink of an Eye: How Vision Kick-Started the Big Bang of Evolution), and curses his vision, for it introduced the concepts of jealousy and unrequited love.

Endosymbiosis (see One Plus One Equals One: Symbiosis and the Evolution of Complex Life), the first animals to appear on land (see Your Inner Fish: The Amazing Discovery of Our 375-Million-Year-Old Ancestor), the evolution of whales (see The Walking Whales: From Land to Water in Eight Million Years), the otherworldly intelligence of the octopus (see my review of Other Minds: The Octopus and the Evolution of Intelligent Life), and, of course, the evolution of man – Wrangham’s argument in Catching Fire: How Cooking Made Us Human is beautifully paraphrased:

“as the unruly flames were turned into a hissing, purring pet, so was the brute himself domesticated, in a feedback loop of momentous occasion.“

These and other important chapters in evolutionary history are retold through the lens of mythology. At the end of the book, in a section called “Illuminations”, Harman provides context and explanation, as well as plenty of recommended reading, both popular accounts and classic papers.

The idea to write an epic poem on evolution’s milestones could have easily ended up a forced, cringe-worthy exercise. Instead, as I hope my liberal quoting above has convinced you, this book is anything but that. Evolutions stands out on account of its unusual take on the subject matter. I do slightly worry that, because of this, it runs the risk of being overlooked amidst the maelstrom of other good pop-science books that are being published. For anyone who enjoys the intersection of art and science, this unique and imaginative book is one to treasure.

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

Evolutions paperback, hardback, ebook or audio CD

Other recommended books mentioned in this review:

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“Extended Heredity: A New Understanding of Inheritance and Evolution“, written by Russell Bonduriansky and Troy Day, published by Princeton University Press in April 2018 (hardback, 288 pages)

Now, to be fair, rebellious as this notion might sound, it is not entirely new. Bonduriansky & Day join a growing chorus of biologists who feel that genetic inheritance is not the whole story. Notable pioneers in this field are Eva Jablonka and Marion Lamb who have been beating this drum for a few decades now (see their books Epigenetic Inheritance and Evolution: The Lamarckian Dimension and Evolution in Four Dimensions: Genetic, Epigenetic, Behavioural, and Symbolic Variation, published in a second edition in 2014). They defined four ways by which evolution might act, while Bonduriansky & Day rather cut the pie in two and talk of genetic and non-genetic inheritance that together form the concept they christen “extended heredity”.

They also rather not raise the spirit of Jean-Baptiste Lamarck. Yes, they say, he was an influential thinker, but his ideas of inheritance of acquired characters only vaguely resemble our current understanding, and the word Lamarckian can have several meanings. So, as opposed to some others (see my review of Lamarck’s Revenge: How Epigenetics Is Revolutionizing Our Understanding of Evolution’s Past and Present), they steer clear of terms such as neo-Lamarckism. But clearly, there was a time when this kind of thinking was in vogue. How did the gene triumph?

Though this book is not a history lesson in the evolution of biological thought in the vein of Sapp’s Genesis: The Evolution of Biology, the authors nevertheless spend a few chapters examining how we got here. Obviously, there was a series of pivotal scientific discoveries: Mendel’s famous crossing experiments with peas (see Mendel’s Legacy: The Origin of Classical Genetics and Gregor Mendel: Planting the Seeds of Genetics), and the elucidation of the structure of DNA (see Watson’s DNA: The Secret of Life). But as the authors show, ideology and politics played just as big a role. There was an enormous backlash against the idea of “soft” heredity in the wake of the horrors unleashed in the communist USSR by the scientifically illiterate agronomist Trofim Lysenko (see for example Lysenko’s Ghost: Epigenetics And Russia).

“Sperm cells have long been caricatured as DNA packages with outboard motors, but carry other factors including RNA”

All this crystallised into the school of thought that became known as the Modern Synthesis (see Evolution: The Modern Synthesis) that gave rise to for example Dawkins’s famous book The Selfish Gene. Non-genetic inheritance was completely off the table, and it is remarkable, with the benefit of hindsight, to read the adamant statements from influential researchers such as Theodosius Dobzhansky or Ernst Mayr that the environment has no way of influencing DNA.

So, what are these forms of non-genetic inheritance then? Obviously, there is epigenetics in the strict sense. The authors take the treatment of the technical details of DNA methylation, histone modification, and RNA inheritance a step up from Carey’s previously reviewed book The Epigenetics Revolution: How Modern Biology is Rewriting Our Understanding of Genetics, Disease and Inheritance. There is the idea that learning and culture are a form of heredity (often put forward to explain how humans set themselves apart, see these three books for more), and there is the influence of the microbiome, which also gets passed on through the generations (see these three books for more).

“[…] the genome cannot be the whole answer for the simple reason that since life’s emergence, transmission of genetic material has happened together with the required replication machinery”

But Bondurianksy & Day offer other fascinating observations. The external morphology of single-celled organisms seems to be copied as a template in an almost mechanical fashion, including “mutilations” that were inflicted experimentally. Egg cells contain molecules and organelles, and both their nature, quantity and location, and how they are divvied up during cell division, matters. Sperm cells have long been caricatured as DNA packages with outboard motors, but carry other factors including RNA. Some of this can even originate from extracellular vesicles that travelled through the body from elsewhere and can fuse with sperm cells before fertilisation. What I didn’t even know is that after fertilisation the first few cell divisions happen under what the authors call a parentally programmed autopilot before the embryo’s genome takes over. One particularly shrewd observation the authors make is that the genome cannot be the whole answer for the simple reason that since life’s emergence, transmission of genetic material has happened together with the required replication machinery: a membrane-enclosed cell with its highly structured cytoplasm and all the material that it contains.

The remainder of Extended Heredity discusses how these ideas can be incorporated into existing evolutionary theory and why it is important. They also dedicate a chapter to deal with oft-voiced critiques and another one to speculate how outstanding puzzles in evolutionary biology could be reconsidered through fresh eyes.

Much more research, both applied and theoretical, will be required before these notions will become part of mainstream biology. In that sense, biological theories are like big ships – changing course is a slow and time-consuming process. Extended Heredity puts itself in the vanguard of this effort and is therefore by definition not the final statement on this topic. No doubt some of the things suggested here will be refuted in years to come. But the book builds a convincing case that non-genetic inheritance both exists and matters. For what is an advanced topic, its treatment could have ended up obtuse and impenetrable to outsiders. Instead, Bonduriansky & Day have written a book of great clarity, and have done so with great care. Whether you are open to the idea of non-genetic inheritance or not, this thought-provoking book deserves a close reading.

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

Extended Heredity paperback, hardback or ebook

Other recommended books mentioned in this review:

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Some recent popular science books on culture as heredity:

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Some recent popular science books on the microbiome:

“She Has Her Mother’s Laugh: The Powers, Perversions, and Potential of Heredity“, written by Carl Zimmer, published in Europe by Picador in August 2018 (hardback, 656 pages)

With the narrative itself sprawling over more than 570 pages, the scope of this book is vast. In the hands of a lesser writer, the prospect of reading such a large book on a technical topic such as heredity might seem daunting. Zimmer, however, is very adept at combining his personal experience as a father with the results from historical and current scientific research, frequently highlighting the many human stories and dramas leading to new findings.

Starting with our understanding of heredity before Darwin, Zimmer walks us through Darwin’s failed attempt at explaining heredity in The Variation of Animals and Plants under Domestication (see also Van Grouw’s recent celebration of that book in Unnatural Selection), the forgotten work of Mendel that was rediscovered decades later, and the “laughably baroque” cell division process of meiosis that results in egg and sperm cells. There is the obsession of many people with genealogy, something that received renewed interest with the falling costs of sequencing technology. Zimmer has his own DNA sequenced and uses this as a hook to talk about ancient DNA recovered from archaeological remains and how this has revealed that we are all complex mosaics of many different ethnic groups, with even some Neanderthal DNA thrown in for good measure! (see also Pääbo’s Neanderthal Man: In Search of Lost Genomes and my review of Reich’s excellent Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past that goes into much more detail).

“If Charles Darwin were to walk into my office today and ask me: “So, what did I miss?” I think I would sit the good man down with a copy of She Has Her Mother’s Laugh“

Mendel’s principle of inheritance is not the only mechanism though. Zimmer goes into the discovery of the complex inheritance of traits such as height and intelligence that rely on small contributions from many genes, the nature/nurture debate and what studies on human twins have revealed, or the astounding discoveries that our bodies are mosaics of genetic variation due to localised mutation, and that some people are even chimaeras containing genetic material from more than two people.

The concept of heredity becomes even fuzzier once we start adding the discovery of the microbiome (the community of microbes that lives in and on us, see these three books for more), epigenetics (heritable changes due to changes in gene activity rather than sequence, see these three books for more), or the notion that culture is a form of heritability to pass on knowledge (see these three books for more). You can see why Bonduriansky & Day are calling for a reappraisal of the concept of heredity in their recent book Extended Heredity: A New Understanding of Inheritance and Evolution.

But what of this misappropriation? Ah yes, the dark side. Throughout all these various chapters Zimmer weaves the troubled contribution mental institutes have made to our understanding of heredity (see Porter’s book Genetics in the Madhouse: The Unknown History of Human Heredity), the subsequent rise of the eugenics movement that hoped to improve the human race through forced sterilization, the horrors of Nazi Germany, and the persistence of the outdated idea of race that for centuries has been used to justify slavery and racism (see strident takedowns in The Myth of Race: The Troubling Persistence of an Unscientific Idea and Superior: The Return of Race Science). Given his own Jewish background, his treatment of these topics is surprisingly dispassionate. Although he obviously opposes all of the above, his assertion that “it’s also a mistake to use Hitler as a label for all of eugenics” (p. 499) and his willingness to discuss Hermann Muller’s ideas on more progressive forms of eugenics shows Zimmer to be open-minded, or at least able to keep his writer’s cool.

“our bodies are mosaics of genetic variation due to localised mutation, and some people are even chimeras containing genetic material from more than two people”

This, of course, brings us to all the ethical quandaries stirred up by the discovery and application of CRISPR (see also my reviews of A Crack in Creation: The New Power to Control Evolution and Modern Prometheus: Editing the Human Genome with CRISPR-Cas9). This new tool to edit genetic material has the ability to cure diseases but could also be used for more questionable ends such as designer babies. There are no simple answers here, and Zimmer gives a great overview of the debates and the rapid pace with which this technique is developing.

As you can see, I have been reading into quite a few of the topics that Zimmer deals with. Even so, the quality of his narrative, the well-placed humorous comparisons, and the human portraits he mixes in make these chapters a joy to read. There were plenty of subjects that were new to me and especially the chapters on human mosaics and chimaeras at times made my eyes widen in astonishment. I envy the reader for who all this material is new – you are going to have a lot of fun reading this book. In that sense She Has Her Mother’s Laugh acts like a portal, introducing you to a huge number of topics relevant to heredity from which you can branch out to read more into areas of interest. The press has heaped praise on this book, calling it magisterial and sweeping. Having devoured the book from cover to cover in a day and a half, I can assure you this is no hyperbole. Zimmer has written an epic book that provides a vast panorama on our current and past understanding of human heredity and genetics.

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

She Has Her Mother’s Laugh paperback, hardback, ebook or audiobook

Other recommended books mentioned in this review:

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Some recent popular science books on the microbiome:

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Some recent popular science books on epigenetics:

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Some recent popular science books on culture as heredity:

Anyway. Sex.

“Mate Choice: The Evolution of Sexual Decision Making from Microbes to Humans”, written by Gil G. Rosenthal, published by Princeton University Press, in August 2017 (hardback, 632 pages)

From the beautiful song and dance of birds-of-paradise, the use of spermatophores (i.e. packages of sperm) as nuptial gifts in insects, the sexual cannibalism (i.e. let’s-have-sex-and-then-I’ll-kill-you) in other insects, pregnant seahorse males, the aggregations of displaying males on so-called leks in grouse or certain antelopes, or the broadcast spawning events of certain fish (i.e. free-for-all mating aggregations that turn the waters into a soup of sperm and eggs)… the world of animal courtship and reproduction is endlessly varied and endlessly fascinating. It has given many a pop-science author an excuse to write amusing and slightly racy books, Howard’s Sex on Earth: A Journey Through Nature’s Most Intimate Moments or Schilthuizen’s Nature’s Nether Regions: What the Sex Lives of Bugs, Birds and Beasts Tell Us About Evolution, Biodiversity and Ourselves being just two recent examples. We serious biologists of course read Shuster & Wade’s Mating Systems and Strategies for an overview.

As Rosenthal observes, the downside of all this diversity is a certain “Balkanization”. There are complete research programmes on mate choice in fish, similarly for birds, frogs and humans. But there isn’t necessarily a lot of cross-talk between the various disciplines of e.g. ethology, neurobiology or evolutionary psychology. And the vastness of the associated literature is such that it’s hard to be an expert in all these fields. Rosenthal’s book is a brave attempt to offer a cross-disciplinary, cross-taxonomical overview of mate choice to bring these fields closer together. Even though it’s not intended as an exhaustive literature review, Rosenthal has read thousands of publications, and the reference section of this chunky book runs to some 112 pages (having been printed on heavy paper stock, this is a doorstopper).

The main point Rosenthal wants to make with Mate Choice is that the role of “good genes” is overrated. One school of thought in mate choice research that has received much attention is the idea that during courtship, one sex (often females) picks a partner (often males) based on traits that indicate good genetic quality. She may not directly benefit from this herself, but her offspring will indirectly gain an evolutionary advantage. Though this mechanism has its role, Rosenthal argues it is minor. Decades of research have failed to turn up much direct evidence. As an aside, Rosenthal talks about courters and choosers, rather than males and females. This is not just political correctness; other than sex-role-reversed species, there is increasing evidence for strong female choice on males in some species, and roles switching back and forth between males and females within one interaction.

“[…] the world of animal courtship and reproduction is endlessly varied and endlessly fascinating”

The first part of this book walks through the actual biological process of mate choice. First there is sensory biology. Before you can choose, you need to detect the courtship signal, whether through smell, sound, or sight. Then there is cognition. In reality, most courters pay attention to several signals, and to several features of each signal (e.g. bowerbird females evaluate the male’s bower, his song, his dance, and his plumage). This requires processing and integrating complex information. A courter ends up preferring not just one trait, but a combination of several traits, a so-called multivariate preference. Then there is evaluation, once observed and processed, a courter needs to decide: is she attracted, indifferent, or repelled by this display? Then comes choice. It’s not uncommon for several courters to be vying for a chooser’s attention. Who do you choose? If not, how many partners do you sample before coming to a decision? And it doesn’t stop there, even during and after mating, choice continues. Sperm can be stored or ejected by females, and strategic decisions can be made on how much time and resources to allocate to offspring (collectively this is known as cryptic choice, as it is harder to observe). And of course, courtship is rarely a one-way street, but a dynamic process that involves give and take by both parties, i.e. mutual mate choice. This part of the book is already fascinating, giving many examples of how different and complex mate choice can be in various creatures.

The middle section of the book discusses variation in preferences and choices among species, between individuals and within individuals. Genetic, environmental (e.g. seasonal), and social (e.g. preferences learned from parents) factors play a large and decisive role in determining the outcome of mate choice.

The final section deals with the origin, evolution, and consequences of mate choice. Where do preferences come from? How does natural selection act on them, i.e. how do they evolve? And, the core focus of current research, how do chooser preferences and courter traits evolve together? Finally, Rosenthal considers the role of mate choice in the formation of new species or their disappearance through hybridization.

“[…] choosers do not always mate with the most attractive courter, but rather pick the least worst”

The range of disciplines covered here reveals many striking findings and is an education in mate choice research. Some things that struck me were that choosers do not always mate with the most attractive courter, but rather pick the least worst. Or the idea that mate choice is rarely fully optimized from the chooser’s point of view. Often, the value of a certain preferred trait, or the combination of preferred traits, simply isn’t present in the current population of courters she finds herself in, or even lies outside of the scope of what is biologically possible. This is how biologists came upon the preference for so-called supernormal stimuli, think of Niko Tinbergen’s findings that seagull chicks preferred dummies of seagull beaks that showed exaggerated colour patterns compared to what parent seagulls normally show.

The information-density is high and it reminded me of reading papers when studying. Sometimes I had to read paragraphs several times to get them. I do not say this to criticize Rosenthal’s writing style; I see it as an inescapable consequence of communicating complex, sometimes abstract ideas at a high level. As such, the audience for this book is clearly an academic one. But if you research mate choice, or are starting out, this book is a benchmark work you need to read. Books with such a wide scope aiming to synthesize a field don’t come along very often. That alone makes this book an important contribution, and I, for one, am glad to have read it. I expect this will become a standard reference work, on par with Birkhead & Møller’s Sperm Competition and Sexual Selection, Andersson’s Sexual Selection, and Shuster & Wade’s Mating Systems and Strategies. The last two were also published by Princeton University Press, so I am pleased to see them continuing a tradition of publishing important works in this field.

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

Mate Choice hardback or ebook

Other recommended books mentioned in this review:

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