Tag Archives: extinction

Salmon or seals?

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Reading Rebecca Nesbit’s Tickets for the Ark for New Scientist, 9 February 2022

Imagine: you are the last person alive. On your dying day, you cut down the last remaining oak tree, just because you can. Are you morally wrong?

Rebecca Nesbit, a science writer who trained as an ecologist, reports from fields where scientific knowledge and moral intuition trip over each other in disconcerting, sometimes headline-generating ways. Her first book, published in 2017, was Is that Fish in your Tomato? exploring the benefits and risks of genetically modified foods.

In Tickets for the Ark, Nesbit explores the moral complexities of conservation. If push came to shove, and their extinction were imminent, would you choose to preserve bison or the Siberian larch; yellowhammers or Scottish crossbills; salmon or seals? Are native species more important than invasive species? Do animals matter for their charisma, or their edibility? Are we entitled to kill some animals to make room for others?

Working through these and other issues, Nesbit shows how complex and problematic conservation can be. In particular, she draws attention to the way we focus our efforts on the preservation of species. This, she points out, is really just a grand way of saying that we preserve what we can easily see. For the sake of preserving the planet’s biodiversity, we might as easily focus on genes, or on individual strings of DNA, or the general shape of whole ecosystems.

Tickets for the Ark could be read as a catalogue of understandable blunders. We have attempted to limit the spread of invasive species, only to discover that many indigenous species are long-established immigrants. We have attempted to reverse human interference in nature, only to find that life has been shaping the Earth’s geology for about 2.5 billion years.

Far from being a counsel of despair, though, Tickets for the Ark reveals the intellectual vistas those blunders have opened up.

Even supposing it ever existed, we know now that we cannot return to some prelapsarian Eden. All we can do is learn how natural systems change (sometimes under human influence, sometimes not) and use this information to shape our present world according to our values.

In a sense, of course, we have always been doing this. What is agriculture, if not a way of shaping of the land to our demands? At least now, having learned to feed ourselves, we might move on to realise some higher ideals.

Once we accept that “nature” is a human and social idea, and that conservation is about the future, not the past, then most of conservation’s most troubling conundrums and contradictions fall away. The death of the last oak, at the hands of the last human, becomes merely the loss of a category (oak tree) that was defined and valued by humans; a loss that was at some point inevitable anyway. And though this conclusion is counterintuitive and uncomfortable, Nesbit argues that it should be liberating because it leaves us “free to discuss logically what we should save and why, and not just fight an anti-extinction battle that is doomed to failure.”

Above all, we can now consider what conservation efforts will achieve for whole ecosystems, and for biodiversity as a whole, without wasting our time agonising over whether, say, British white-clawed crayfish are natives, or dingoes are a separate species, or whether we are morally entitled to introduce bison to clear the steppe of Siberian larch (a native species, but responsible for covering, and warming, ancient carbon-sequestering permafrost).

Nesbit’s ambitious and entertaining account foresees a dynamic and creative role for conservation, especially in an era of potentially catastrophic climate change. Having freed ourselves of the idea that species belong only in their past ranges, and armed with better information about how ecosystems actually work, it may be time for us to govern the spread of bison and countless other species into new ranges. A brave proposal; but as Nesbit points out, translocation may be the only option for some species.

Tally of a lost world

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Reading Delicious: The evolution of flavor and how it made us human by Rob Dunn and Monica Sanchez for New Scientist, 31 March 2021

Dolphins need only hunger and a mental image of what food looks like. Their taste receptors broke long ago, and they no longer taste sweet, salty or even umami, thriving on hunger and satisfaction alone.

Omnivores and herbivores have a more various diet, and more chances of getting things badly wrong, so they are guided by much more highly developed senses (related, even intertwined, but not at all the same) of flavour (how something tastes) and aroma (how something smells).

Evolutionary biologist Robb Dunn and anthropologist Monica Sanchez weave together what chefs now know about the experience of food, what ecologists know about the needs of animals, and what evolutionary biologists know about how our senses evolved, to tell the story of how we have been led by our noses through evolutionary history, and turned from chimpanzee-like primate precursor to modern, dinner-obsessed Homo sapiens.

Much of the work described here dovetails neatly with work described in biological anthropologist Richard Wrangham’s 2009 book Catching Fire: How cooking made us human. Wrangham argued that releasing the calories bound up in raw food by cooking it led to a cognitive explosion in Homo sapiens, around 1.9 million years ago.

As Dunn and Sanchez rightly point out, Wrangham’s book was not short of a speculation or two: there is, after all, no evidence of fire-making this far back. Still, they incline very much to Wrangham’s hypothesis. There’s no firm evidence of hominins fermenting food at this time, either — indeed, it’s hard to imagine what such evidence would even look like. Nonetheless, the authors are convinced it took place.

Where Wrangham focused on fire, Dunn and Sanchez are more interested in other forms of basic food processing: cutting, pounding and especially fermenting. The authors make a convincing, closely argued case for their perhaps rather surprising contention that “fermenting a mastodon, mammoth, or a horse so that it remains edible and is not deadly appears to be less challenging than making fire.”

“Flavor is our new hammer,” the authors admit, “and so we are probably whacking some shiny things here that aren’t nails.” It would be all too easy, out of a surfeit of enthusiasm, for them distort their reader’s impressions of a new and exciting field, tracing the evolution of flavour. Happily, Dunn and Sanchez are thoroughly scrupulous in the way they present their evidence and their arguments.

As primates, our experience of aroma and flavour is unusual, in that we experience retronasal aromas — the aromas that rise up from our mouths into the backs of our noses. This is because we have lost a long bone, called the transverse lamina, that helps to separate the mouth from the nose. This loss had huge consequences for olfaction, enabling humans to search out convoluted tastes and aromas so complex, we have to associate them with memories in order to individually categorise them all.

The story of how Homo sapiens developed such a sophisticated palette is also, of course, the story of how it contributed to the extinction of hundreds of the largest, most unusual animals on the planet. (Delicious is a charming book, but it does have its melancholy side.)

To take one dizzying example, the Clovis peoples of North America — direct ancestors of roughly 80 per cent of all living native populations in North and South America — definitely ate mammoths, mastodons, gomphotheres, bison and giant horses; they may also have eaten Jefferson’s ground sloths, giant camels, dire wolves, short-faced bears, flat-headed peccaries, long-headed peccaries, tapirs, giant llamas, giant bison, stag moose, shrub-ox, and Harlan’s Muskox.

“The Clovis menu,” the authors write, “if written on a chalkboard, would be a tally of a lost world.”