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Through actions big and small, intentional and unintentional, we are reshaping life on Earth

Life Changing: How Humans are Altering Life on Earth

Helen Pilcher
Bloomsbury Sigma
384 pp.
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Hailing from rare wild mutants, the golden gnu, an uncharacteristically fawn-colored wildebeest, was for the past decade at the center of a speculation bubble in the African trophy-hunting business. Owners of wildlife preserves banked on hunters being willing to part with large sums for the privilege of shooting these beasts, and breeding stock changed hands for up to US$500,000 per animal. The speculators were wrong. The price people were prepared to pay was nowhere near what ranchers had hoped. Prices plummeted and reserve owners were left with herds of worthless mutant wildlife.

This is one of many tales Helen Pilcher tells in Life Changing, the central theme of which is how humans are, more deeply and pervasively than ever before, changing nature. She interprets her brief broadly, loosely weaving together intentional as well as accidental changes, (self-)domestication, conventional breeding, genetic modification (including CRISPR-Cas9), cloning, de-extinction, sterile male and kamikaze-gene techniques, hybridization, contemporary evolution, assisted evolution, conservation genetics, and rewilding.

Pilcher presents these stories in a pleasant, chatty style, garnished with funny asides. Part of the book consists of retellings of stories from other recent books on this topic (1–3). Still, it covers some new ground and makes for exciting reading, especially when Pilcher gives firsthand accounts of, for example, a captive breeding program for the endangered kākāpō parrot in New Zealand or an “assisted evolution” facility for coral at London’s Horniman Museum.

Pilcher tends to skirt around the more challenging parts of her subjects, such as the evolutionary biology of how species have adapted, and continue to adapt, to humans. When her examples involve her own academic field (cellular biology), however, she is on more secure footing. Her tale of the world of horse-cloning techniques and their implications, for instance, is fascinating.

Around 10 years ago, Argentinian polo champion Adolfo Cambiaso produced no fewer than six copies of his favorite mare, Cuartetera. In polo, players can change to fresh horses throughout the game, meaning that Cambiaso can ride multiple clones in a single match.

Toward the end of the book, Pilcher surveys her portfolio of human-induced changes in the world’s species and ponders what their impact will be on ecosystems of the future. She reminds readers of Darwin’s words that natural selection is “immeasurably superior to man’s feeble efforts” and that there is hubris in thinking that we can fix the environment using technology.

Her chapter on rewilding shows how new ecosystems will appear, as if by magic, if we stop interfering with nature. The Knepp estate in England, for example, where feral pigs play their original role as a keystone species, is now a mosaic of habitats where rare species, once characteristic of the English half-open forest landscape, abound.

Pilcher waxes lyrical about successful attempts to save biodiversity by micromanaging species’ genetic makeup, as has been done to prevent inbreeding in the precariously small Kākāpō population. Unfortunately, the vertebrate component of biodiversity is negligible compared with the huge numbers of nonvertebrate organisms that make up the bulk of the food web. To this point, when the remaining wild Kākāpōs entered the captive breeding program, they were dewormed, which probably drove to extinction Stringopotaenia psittacea, the kākāpō’s unique tapeworm species. For all its technological prowess, the net biodiversity benefit of the Kākāpō Recovery Program is probably exactly zero.

While the ultimate impact of intentional modification of species should not be oversold, the unintentional impact of our actions on the world’s ecosystems might be even vaster than Pilcher dares imagine. Forecasting these changes will be impossible, and only time will tell how those ecosystems will look and function.

References and notes
1. L. A. Dugatkin, L. Trut, How to Tame a Fox (and Build a Dog) (Univ. of Chicago Press, 2017).
2. T. Kornfeldt, The Re-Origin of Species (Scribe, 2018).
3. K. van Grouw, Unnatural Selection (Princeton Univ. Press, 2018).

About the author

The reviewer is at the Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, Netherlands.