I picked this up from the library after reading an enthusiastic review, but by the time I got home I was wondering when I'd find the time and energy to read it. I needn't have worried - I found this as absorbing and hard to put down as a good novel, probably because of Kolbert's personal and engaging writing style and the fascinating examples she uses to introduce the wider themes of the book. Each chapter uses a specific extinct or endangered species as a window on to our understanding of extinctions, or some aspect of the "Sixth Extinction", the mass extinction caused by the impact of humans on the natural world:
- Atelopus zeteki, the Panamanian golden frog, now extinct in the wild due to chytrid fungi, believed to have been spread recently by humans moving other species of frog between continents;
- Mammut americanum, the American mastodon, which disappeared in the 'megafauna extinction' that coincided(!) with the spread of modern humans, and whose bones led the French naturalist Cuvier to propose the concept of extinction in 1796;
- Pinguinus impennis, the great awk, slaughtered wholesale over a few hundred years by seamen who found their breeding colony off the coast of Newfoundland a source of easy food. (I found this chapter particularly sad.) Kolbert cites this as an example of a contemporary 'cataclysmic' extinction that challenged Darwin's view that gradual natural selection could account for all historic extinctions;
- Discoscaphites jerseyensis, an example of an ammonite, a type of marine invertebrate that was wiped out (along with the dinosaurs) in the end-Cretaceous extinction, now widely believed to have been caused by the aftermath of an asteroid's impact;
- Dicranograptus ziczac, a tiny marine organism or 'graptolite' that disappeared, along with most graptolites, at the end of the Ordovician period, probably due to glaciation, illustrating the point that the cataclysms that cause mass extinctions are varied. This chapter also describes the proposal to officially declare a new 'Anthropocene' geological epoch to recognise the recent human transformation of the Earth's geology through activities such as deforestation, damming rivers, and burning fossil fuels;
- Patella caerulea, a limpet threatened (like all shell-creating 'calcifiers') by "global warming's equally evil twin" ocean acidification, another major effect of the rising carbon dioxide levels produced by burning fossil fuels;
- Acropora millepora, a type of coral, another calcifier which is severely threatened by (amongst other things) ocean acidification, with some experts predicting that all reefs will have begun to dissolve within the next fifty years;
- Alzatea verticillata, a tree that in a study of a series of plots at different elevations (and therefore temperatures) in Peru does not appear to 'migrate' by dispersing seeds up the mountain as temperatures rise, and therefore appears to lack resilience to climate change;
- Eciton burchellii, an army ant, whose complex system of followers (such as birds that eat the insects they disturb, and butterflies that eat the birds' droppings) find it hard to survive in reduced 'forest fragments' in the Amazon, showing the disproportionately disruptive effect that deforestation can have;
- Myotis lucifugus, a bat under threat from 'white-nose syndrome', a cold-loving fungus recently imported to the US, where it is proving deadly to the bat population (an example of how "we are, in effect, reassembling the world into one enormous supercontinent - what biologists sometimes refer to as the New Pangaea");
- Dicerorhinus sumatrensis, one of only around a hundred remaining Sumatran rhinos, used to introduce a discussion of "oversized" animals whose lack of natural predators more than compensated for their slow reproductive cycles - until humans came along. According to this account of the megafauna extinction, "though it might be nice to imagine there was once a time when man lived in harmony with nature, it's not clear that he ever really did";
- Homo neanderthalensis, the Neanderthal, probably wiped out by us through a process of 'leaky replacement' that means that "all non-Africans ... carry somewhere between one and four percent Neanderthal DNA". In attempting to describe the unique qualities of humans that make us so powerful and therefore deadly, she describes a project to study Neanderthal DNA in search of "the mutations that make us the sort of creature that could wipe out its nearest relative, then dig up its bones and reassemble its genome";
- Homo sapiens: since we too depend on the biological and geochemical systems that we are so disruptive to...
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