Overview

Fungi are not plants. They are not animals. They are a weird third kingdom that rules the world. They are the recyclers. Without fungi, the world would be buried under miles of dead trees and animal bodies. They digest the dead to make life for the living.

Core Idea

The core idea is The Wood Wide Web. The mushroom you see is just the fruit (like an apple). The real organism is the Mycelium—a vast underground network of white threads. These threads connect trees to each other, allowing them to share nutrients and warn each other of pests.

Formal Definition

The study of fungi. Fungi are heterotrophs (they eat food) like animals, but they digest it outside their bodies by secreting enzymes, then absorb the nutrients.

Intuition

  • Plants: Make food (Producers).
  • Animals: Eat food (Consumers).
  • Fungi: Rot food (Decomposers). They are the stomach of the earth.

Examples

  • Penicillin: The first antibiotic came from a mold (Penicillium). Fungi are experts at chemical warfare because they have to fight bacteria for food in the soil.
  • Yeast: A single-celled fungus. Without it, we have no bread, no beer, and no wine. It eats sugar and burps CO2 (bubbles) and alcohol.
  • Zombie Ants (Cordyceps): A fungus that infects an ant’s brain, forces it to climb a tree, and then explodes out of its head to shower spores on the colony below.

Common Misconceptions

  • Mushrooms are vegetables: Biologically, they are closer to humans than to carrots. They breathe oxygen and have chitin (like insect shells) in their cell walls.
  • All fungi are mushrooms: Most are microscopic molds or yeasts.
  • Mycorrhiza: The symbiotic partnership between fungi and plant roots. 90% of plants depend on this to grow.
  • Psilocybin: The psychoactive compound in “Magic Mushrooms.” Currently being studied to treat depression and PTSD.

Applications

  • Mycoremediation: Using fungi to clean up oil spills and eat plastic.
  • Myco-materials: Growing bricks and leather out of mycelium. It is biodegradable and strong.

Criticism / Limitations

  • Pathogens: Fungal infections (like Candida or Black Mold) are hard to treat because their cells are so similar to ours. Drugs that kill them often hurt us.

Further Reading

  • Sheldrake, Merlin. Entangled Life. 2020. (A masterpiece on fungi).
  • Stamets, Paul. Mycelium Running. 2005.