wWhen Charles Darwin published On the Origin of Species in 1859, the Industrial Revolution and British colonialism were in full swing. Charles Dickens published Hard Times five years ago; Queen Victoria nominally ruled over one-fifth of the world’s population. Science writer Rowan Hooper writes, Darwin devised his evolutionary theory to present what he thought his audience wanted to hear: “a description of nature as competitive struggle”. Natural selection began in a world that was “colonial, capitalist, patriarchal, and ruled by the upper class” – and Darwin’s central message, what the philosopher Herbert Spencer called “survival of the fittest”, coincided with the times.
Hopper admires Darwin – his description of visiting Down House, Darwin’s Kent residence, reflects reverence (“It’s a pseudo-religious experience”). But he feels that Darwinism and its association with genetics in the so-called “modern synthesis” have placed undue emphasis on competition in the natural world and downplayed the roles of cooperation and collaboration. In redressing that imbalance, solidarity is not an attempt to make development more embraceable and palatable; Rather, it is a corrective measure deeply rooted in what we have learned since Darwin about how nature works. Written with immense charm and passion, and packed with startling facts, it is also a plea for the wonders of nature and the value and urgency of preserving them.
It is quite easy to see the competitive side of nature: the lion chasing the deer, the bird of prey swooping down for prey. But the photogenic animal kingdom is not necessarily the most representative resource for the natural historian. Hopper shows that we often find a very different story between soft, sticky, and gooey things: fungi, microbes, mushrooms. and lichens, which superficially look like plants but are actually a partnership between fungi and algae. Each supplies something to the other: algae can photosynthesize, producing carbohydrates on which fungi feed, while fungi provide shelter and disperse light-gathering algae. This relationship is symbiotic: each organism is dependent on the other and they grow and develop together. Sometimes the lichen group is joined by other partners: cyanobacteria (photosynthetic bacteria) or yeast. It’s a fantastically productive partnership, enabling lichens to thrive almost anywhere, from rainforests to tundra and desert.
Or take coral. These colorful, branching sea creatures invite classification as plants, but are actually a collaboration of animals (cnidarians, the same family as sea anemones and jellyfish) and the algae that live in their stomachs. Algae photosynthesize using sunlight while host animals deliver nutrients and carbon dioxide to their guests. (Some deep-sea corals, which grow in the dark, host bacteria instead.) After observing them on the voyage of the Beagle, Darwin published a book on coral reefs in 1842, describing how their limestone shells formed entire island atolls. But they had no idea that they were symbiotes.
Most land plants depend on symbiotic fungi, particularly root fungi called mycorrhizae, which provide vital nutrients such as nitrogen and phosphorus. Without these associations there would be no forests and grasslands on land, but only mats and layers of microbial colonies. Orchids are ideal plant symbioses – individual plants are interconnected through an underground fungal network through which they can send sugars to their shoots.
These are not, as previously imagined, antagonisms: symbiosis is the natural state of most organisms. Beetles and termites grow nutritious fungal gardens in their nests. And the importance of the bacteria in and on our bodies – our microbiome – has become increasingly clear. Antibiotics that eliminate them leave us with digestive disorders, while some recurring bacterial infections and even depression can be treated with fecal transplants, which sounds far-fetched but is no more or less than restocking our microbial allies.
Symbiosis has driven growth since its early days. Chloroplasts, responsible for photosynthesis in plant cells, were once free-living cyanobacteria. Mitochondria were also the ones that produce energy in our own cells. Such a permanent symbiotic merger of single-celled organisms (endosymbiosis) was first proposed in the 1960s by biologist Lynn Margulis, who claimed that the “red in tooth and claw” Darwinian view of evolution was “naïve”. “We now see ourselves as products of cellular interactions,” he wrote in 1987. Such a merger could allow development to move forward not in small steps but in giant leaps, he said.
Margulis’s endosymbiosis hypothesis is now accepted, but it initially faced skepticism and even ridicule. Sexism has certainly played a role in this, but there is a thesis to be written on the resistance of academic biology to the notions of cooperation and collaboration in evolution – or its determination to relegate them to mere expediency by “selfish genes”. Margulis makes the gender-essentialist claim that skepticism about symbiosis is a rejection of “femininity,” but one can’t help noticing that the emphasis on interconnectedness in the natural world often comes from women, whether it’s Rachel Carson’s Silent Spring or forestry scientist Suzanne Simard’s “Wood Wide Web,” the inspiration for a character in Richard Power’s 2018 eco-fable The Overstory.
These interdependencies are vital to the health of the biosphere. For example, warming oceans causes catastrophic “bleaching” of coral reefs, because symbiotic algae cannot tolerate warmer waters. Without them, corals are doomed, and reefs have already halved since the mid-20th century. But, as Hooper points out, symbiosis itself is a delicate balance and can turn into parasitism if one partner turns away from the arrangement. However, he cautions that ultimately the language of competition and cooperation is anthropomorphic and imposes moral judgments on the workings of nature.
My review copy of Togetherness is now going “Wow!” is full of marginal notes. I never knew that the feel-good neurotransmitter serotonin is made mostly by our gut bacteria. Some ants produce antibiotics that they apply to their partners’ wounds. Cockroaches’ bacterial symbionts give them their monstrous (in our opinion) ability to live almost anywhere and eat almost anything. Hopper’s background in conservation biology and his extensive travels (I suppose being an editor at New Scientist has its advantages) bring his accounts to life. While he mistakenly claims that living organisms reduce entropy, sometimes conflates symbiosis and interdependence (predators still need their prey), and somewhat exaggerates the “outrage and horror” caused by Darwin’s origins among “religious authorities”, these are minor quibbles.
Darwin himself was too clever a naturalist to ignore the interdependencies of nature. He did not know the symbiotic secrets of corals or lichens, but he was fascinated by orchids, and ecological sensitivity, as we will now see, permeates his writings. Origen’s famous final passage (“The endless form most beautiful”) emphasizes not nature’s brutal individualism but its web of coexistence. “It is interesting,” Darwin wrote, “to contemplate a tangled bank, covered with so many varieties of plants… These elaborately constructed forms, so different from each other, and dependent on each other in such an intricate manner.”
This is the Darwinian message we most need to hear today. Hooper writes, “The nature crisis we are facing has been caused by a failure to see it in ecological terms, a failure established by our philosophical and economic systems.” “We are symbiotic creatures at the deepest level of our cells.” He says that the feeling of unity with nature is not woolly green fantasy or pre-scientific mysticism. It reflects our best understanding of life and should be heeded.
