Entangled Life: How Fungi Make Our Worlds, Change Our Minds and Shape Our Futures

by Merlin Sheldrake

Cords and rhizomorphs are a good reminder that mycelial networks are transport networks.

For this to happen, water must travel rapidly through the network from one place to another, and flow into a developing mushroom in a carefully directed pulse.

Holy fucking shit

Over short distances, substances can be transported through mycelial networks on a network of microtubules – dynamic filaments of protein that behave like a cross between scaffolding and escalators. Transport using microtubule ‘motors’ is energetically costly, however, and over larger distances the contents of hyphae travel on a river of cellular fluid. Both approaches allow rapid transport across mycelial networks. Efficient transport allows different parts of a mycelial network to engage in different activities. When the English country house Haddon Hall was being renovated, a fruiting body of the dry rot fungus Serpula was found in a disused stone oven. Its mycelial connections wound back through 8 metres of stonework to a rotting floor elsewhere in the building. The floor was where it fed, the oven was where it fruited.21

To provoke a response in a plant, one would have to expose it to light levels hundreds of times higher.

Phycomyces was ‘the most intelligent’ of the simpler multicellular organisms.

Although Phycomyces is an unusually sensitive species, most fungi are able to detect and respond to light (its direction, intensity or colour) temperature, moisture, nutrients, toxins and electrical fields. Like plants, fungi can ‘see’ colour across the spectrum using receptors sensitive to blue light and red light

The Darwins’ main point is that growing tips – which pilot roots and shoots – must be the place where information comes together to link perception and action, and determine a suitable course for growth. The same applies to fungal hyphae.

A given mycelial network might have anywhere between hundreds and billions of hyphal tips, all integrating and processing information on a massively parallel basis.

Moreover, the cells in a mycelium are continuous with one another, possibly allowing impulses initiated in one part of the network to reach another part without interruption.

Electrical activity can only play a role in fungal communication if it is sensitive to stimulation.

When the wood came into contact with the mycelium, the firing rate of the impulses doubled. When he removed the block of wood, the firing rate returned to normal. To make sure that the fungi weren’t responding to the weight of the wooden block, he placed an inedible plastic block of the same size and weight onto the mycelium. The fungus didn’t respond.

Neurotransmitter molecules pass across synapses, and allow different neurones to behave in different ways – some excite other neurones, some inhibit them. Mycelial networks don’t share any of these features.

‘You do not need much knowledge of how computers work to realise that such systems can create decision gates,’

fungal computer may sound fantastical, but ‘biocomputing’ is a fast-growing field.

These prototype biocomputers use slime moulds to solve a range of geometrical problems. The slime mould networks can be modified – for instance, by cutting a connection – to alter the set of ‘logical functions’ implemented by the network. Adamatzky’s idea of a ‘fungal computer’ is just an application of slime mould computing to another type of network-based organism.35

Rather, he thinks humans could use mycelium growing in an ecosystem as a ‘large-scale environmental sensor’. Fungal networks, he reasons, are monitoring a large number of data streams as part of their everyday existence.

Fungi could report changes in soil quality, water purity, pollution or any other features of the environment that they are sensitive to.

His dream is to ‘hook up a fungus with a computer and communicate with it’, to use electrical signals to get the fungus to change its behaviour. ‘All sorts of weird and wonderful experiments could be done if this turns out to be right.’

Rather, we should assess the degree to which an organism might be cognisant. In all these views, intelligent behaviours can arise without brains. A dynamic and responsive network is all that’s needed.

In this view, complex behaviours – including minds and the nuanced textures of lived, conscious experience – arise out of complex networks of neurones flexibly remodelling themselves.

head, it would retain the memory when it had grown a new head and brain. Remarkably, the answer is yes.

Most nerves in octopuses are not found in the brain, for instance, but are distributed throughout their bodies. A large number are found in the tentacles, which can explore and taste their surroundings without involving the brain. Even when amputated, tentacles are able to reach and grasp.

The ‘tangled network’ they form, the dimensions of the hyphae, the dimensions of spore-like structures and the pattern of its growth all closely resemble modern-day fungal mycelium. It is an extraordinary discovery because the fossils date from 2.4 billion years ago, more than a billion

Not because they have found ways to do what humans can do, but because a life lived rooted to one spot has coaxed them to evolve countless ‘ingenious mechanisms’ to deal with challenges that animals might avoid by simply running away. We could say the same of fungi. Mycelium is one such ingenious

solution, a brilliant reply to some of life’s most basic challenges.

Like a well-exercised muscle, ‘network’ has hypertrophied into a master concept. It is hard to think of a subject that networks aren’t used to make sense of.

How do mycelial fungi work as networks? How do they sense their environment? How do they send messages back to other parts of themselves? How are those signals then integrated?

‘Each step that we make in the more intimate knowledge of nature leads us to the entrance of new labyrinths.’

Instead, he argued that they were composed of two quite different entities: a fungus and an alga.

lichen fungus (known today as the mycobiont) offered physical protection and acquired nutrients for itself and for the algal cells. The algal partner (known today as the photobiont, a role sometimes played by photosynthetic bacteria) harvested light and carbon dioxide to make sugars that provided energy.

principle. They were a gateway organism to the idea of symbiosis, an idea that ran against the prevailing currents in evolutionary thought in the late nineteenth and early twentieth centuries, best summed up in Thomas Henry Huxley’s portrayal of life as a ‘gladiator’s show … whereby the strongest, the swiftest and the cunningest live to fight another day’.

Lichens encrust as much as 8 per cent of the planet’s surface, an area larger than that covered by tropical rainforests.

In 2006, the faces of the presidents carved into Mount Rushmore were pressure-hosed, removing more than sixty years of lichenous growth in the hope of extending the lifetime of the memorial. The presidents aren’t alone.

Described by locals as ‘leprosy’, lichens are deforming the features of the statues, and softening the rock to a ‘clay-like’ consistency.

Lichens mine minerals from rock in a two-fold process known as ‘weathering’. First, they physically break up surfaces by the force of their growth. Second, they deploy an arsenal of powerful acids and mineral-binding compounds to digest the rock. Lichens’ ability to weather makes them a geological force, yet they do more than dissolve the physical features of the world. When lichens die and decompose, they give rise to the first soils in new ecosystems. Lichens are how the inanimate mineral mass within rocks is able to cross over into the metabolic cycles of the living.

Above the tideline, it is only after several metres of lichens and mosses that larger trees start to appear, rooted in crevices well beyond the water’s reach where young soils have been able to form.

In this way, a bacterium can acquire characteristics ‘ready-made’, speeding up evolution many times over. By exchanging DNA, a harmless bacterium can acquire antibiotic resistance and metamorphose into a virulent superbug in a single move. Over the last few decades it has become clear that bacteria aren’t alone in this ability, although they remain its most adept practitioners:

The capacity of lichens to survive in space has since been demonstrated in a number of studies, and the findings are broadly the same. The hardiest lichen species can recover their metabolic activity in full within twenty-four hours of being rehydrated, and are able to repair much of the ‘space-induced’ damage they may have sustained. In fact, the toughest species – Circinaria gyrosa – has such high survival rates that three recent studies decided to expose samples to even higher levels of radiation than they receive in space, to test them to their ‘uttermost limits of survival’. Sure enough, a dose of radiation could kill the lichens, but the amount required to disrupt their cells was enormous. Lichen samples exposed to 6 kilograys of gamma irradiation – six times the standard dose for food sterilisation in the United States, and 12,000 times the lethal dose for humans – were entirely untroubled. When the dose was doubled to 12 kilograys – 2.5 times the lethal dose for tardigrades – the lichens’ ability to reproduce was impaired, although they survived and continued to photosynthesise with no apparent problems.

Amazing!

No wonder that lichens loom – if not large, then certainly vivid – at the front and centre of the panspermia debate.

Lynn Margulis

Eukaryotes arose when a single-celled organism engulfed a bacterium, which continued to live symbiotically inside it. Mitochondria were the descendants of these bacteria. Chloroplasts were the descendants of photosynthetic bacteria that had been engulfed by an early eukaryotic cell. All complex life that followed, human life included, was a story of the long-lasting ‘intimacy of strangers’.23 The

The earliest eukaryotic cells could be thought of as ‘quite analogous’ to lichens, she argued. Lichens continued to figure prominently in her work over the following decades. ‘Lichens are remarkable examples of innovation emerging from partnership,’ she later wrote. ‘The association is far more than the sum of its parts.’

Lederberg demonstrated that bacteria can horizontally acquire genes. The endosymbiotic theory proposed that single-celled organisms had horizontally acquired entire bacteria. Horizontal gene transfer transformed bacterial genomes into cosmopolitan places; endosymbiosis transformed cells into cosmopolitan places.

Likewise, the ancestors of today’s plants horizontally acquired bacteria with the ability to photosynthesise, ready-evolved.

The ancestors of today’s plants didn’t acquire a bacterium with the ability to photosynthesise: they emerged from the combination of organisms that could photosynthesise with organisms that couldn’t.

By comparison with plant cells which can’t be parted from their chloroplasts, lichens’ relationships are open.

In other situations, lichen fungi produce spores that travel alone. Upon arrival in a new place, the fungus must meet a compatible photobiont and form their relationship afresh.

neither. Just as the chemical elements of hydrogen and oxygen combine to make water, a compound entirely unlike either of its constituent elements, so lichens are emergent phenomena, entirely more than the sum of their parts.

Dehydration also protects them from the most hazardous consequence of cosmic rays: highly reactive free radicals, produced when radiation cleaves water molecules in two, that damage the structure of DNA.

Many fungi that produce compounds of importance to humans – including penicillin moulds – lived as lichens earlier in their evolutionary history but have since ceased to do so. Some researchers suggest that a number of these compounds, penicillin included, may have originally evolved as defensive strategies in ancestral lichens and persist today as metabolic legacies of the relationship.