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

Nonfiction | Book | Adult | Published in 2020

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Summary

Background

Chapter Summaries & Analyses

Prologue-Introduction

Chapters 1-2

Chapters 3-4

Chapters 5-6

Chapters 7-Epilogue

Key Figures

Themes

Index of Terms

Important Quotes

Essay Topics

Themes

Fungi’s Role in Evolution and Biodiversity

Fungi were one of the first life forms to appear on land. The first fungi likely grew as gigantic, tree-like prototaxites, which dominated Earth for over 40 million years before green algae emerged from the shallow seas and began to colonize the Earth’s surface. These green algae are the ancestors of all plants, but they would not have successfully survived without the help of fungal partners.

Fungi-plant partnerships take many forms. Fungi, bacteria, and algae can combine into lichens, which have existed for millions of years across huge swaths of the planet. Lichens can survive in extreme conditions and are often the only life forms found where others could not possibly grow. Mycorrhizal relationships, in which fungi inhabit the roots of land plants, began to occur as soon as roots appeared. These partnerships are beneficial to both plants and fungi, and form the basis for the huge underground networks known as the “wood wide web.” Roots themselves would likely not exist without fungi. Fungi’s ability to decompose nearly any organic structure created soil—a substance that the vast majority of root systems depend on for nutrients and stability. The ancient cooperation between plants and fungi likely guided the way that plants developed and allowed for the vast biodiversity seen throughout Earth’s history.

In addition to their immense influence on plants’ ability to survive and evolve, fungi have played a part in guiding animal and insect evolution. On the most basic level, insects and animals would not have achieved the diversity seen today if fungi had not helped create a large range of plant food sources. The complex chemical and electrical signals sent between plants and fungi can render plants more attractive to pollinators, make plants more appealing to eat as a way of spreading seeds, or make them less appealing to swarms of destructive insects. In this way, fungi help keep populations stable and allow all plants, animals, and insects to exist in functional ecosystems. Fungi have also had an impact on the Earth’s climate. By helping increase photosynthetic plant diversity in the Devonian period, fungi contributed to a decline in atmospheric carbon, which made the atmosphere cooler. Entangled Life makes it clear that fungi are a critical part of both the large-scale history of life on earth and the stability of small-scale biomes.

Humans’ Relationship with Fungi

Entangled Life discusses the myriad ways in which humans have used fungi and fungi have used humans. Every person on earth is home to a microbiome, a complex array of bacteria that live in all parts of the body and aid in primary biological functions. Without these fungi and bacteria, humans would be less able to digest food and more susceptible to disease. Sheldrake worries that modern antibiotics and antifungals, as well as sterile agricultural practices, will permanently damage the human microbiome with devastating consequences. By increasing the use of fungi in agriculture, Sheldrake believes that people can improve not only their own health but the health of the soil. Many modern agricultural species live precarious lives in soil free from the nutrients and physical stability that fungi provide. By reintroducing complex suites of mycelium to farmland, producers may be able to create more stable, sustainable crops. Agriculture is just one small aspect of what Sheldrake and his cohorts see as fungi’s potential. Some people believe that fungi will literally save the world and have embarked on projects to use the organisms to build products, help endangered species, and destroy harmful waste.

This is not a new phenomenon, as people have been fascinated by fungi for thousands of years. Fungi, specifically yeast, may have played a role in early agriculture. The Ice Man, a Neolithic hunter famously found mummified in the Alps, had been carrying fungal medicine and fire-starting tinder mushrooms when he died. Mushroom effigies have been discovered in archaeological sites around the world. In many areas, such as Mexico, psychedelic mushrooms have been an important part of shamanic work for many centuries. The potential within psychedelic mushrooms is of particular interest to Sheldrake. He believes that the psilocybin compound can be used to alter humans’ relationship with nature, as most people who have consumed it report an increased feeling of connection to other species. Psilocybin can also be used in a clinical setting, as an effective treatment for depression and other ailments.

However, despite the long history of human-fungi relationships, there is still a strong aversion to them among many people. “Mycophobic” cultures describe fungi as dangerous and dirty. Fear of fungus has led to the common myth that most fungal species are poisonous and should be avoided at all costs. One of Sheldrake’s main goals in writing Entangled Life was to share the fascinating truths of fungi with the nonmycologist world and to help bring understanding to a misunderstood kingdom of life.

The Internal Mechanisms of Fungal Life

Fungi are extremely complex and are just beginning to be understood. Much of Entangled Life is dedicated to explaining how fungi work and just how much is still unknown about them. The vast majority of fungi exist as mycelia, networks of thin filaments known as hyphae that can grow into nearly any shape or size. Fungi have been shown to change their growth patterns to suit their current needs, such as the worm-eating fungus that grows sticky nets when there are many worms available and little other food. Some fungi exhibit a wide range of abilities and internal mechanisms, while others pool all their resources into one or two primary functions. Truffles, for example, appear to be almost exclusively driven to smell so appealing that animals dig them up and spread their spores.

Sheldrake explores the growth patterns displayed by mycelial networks that show something that may be classified as intelligence. Fungal spores are able to reconstruct human road and train networks, working their way through miniature versions of human cities in search of the shortest route to a food source. Mycelial networks also appear to have a kind of memory; when a group of hyphae has located food, other parts of that mycelium can find the food almost immediately even if they are broken off from the hyphae with no direct contact to it. Experiments show that communication happens between different parts of fungal networks; when a bioluminescent fungus is harmed in one spot, a wave of energy passes through the entire network, lighting up the fungus as it travels.

The exact ways that fungi communicate with each other and with other organisms is still poorly understood. Research has proven, however, that mycelial networks are able to transport a huge range of things, including chemical signals, electric impulses, nutrients, and water. Mycelium displays internal structures similar to complex formations like animal brains and the internet, but it is likely very dissimilar to either. For one thing, fungal networks are completely decentralized; a new fungus can grow from just one spore of an old fungus, and if part of a network is cut off, new hyphae will grow in its place. Additionally, fungal networks are not bound to physical constraints like brains are, and they transport a wide range of materials and signals, whereas the internet is exclusively an electrical network. Sheldrake hopes that increased interest in fungal research will begin to unravel the mysteries of mycelium and lead to a better appreciation of their importance.