Fungi

What are Fungi?

Fungi are a distinct kingdom of living organisms—separate from plants, animals, and bacteria—that include yeasts, molds, rusts, mildews, and mushrooms.

Unlike plants, fungi cannot make their own food through photosynthesis. Instead, they absorb nutrients from their surrounding environment.

Key Characteristics of Fungi

• Cell Walls Made of Chitin: Unlike plant cell walls (which are made of cellulose), fungal cell walls contain chitin, the same tough, flexible material found in the exoskeletons of insects and crustaceans.

• Heterotrophic Nutrition: Fungi secrete digestive enzymes into their food source (organic matter, living tissue, or soil) to break it down externally, then absorb the resulting simple nutrients.

• Body Structure: The main body of a fungus usually consists of a network of tiny, thread-like structures called hyphae, collectively known as a mycelium. What we commonly recognize as a “mushroom” is actually just the temporary reproductive fruiting body of a much larger, hidden underground organism.

Major Ecological and Practical Roles

• Decomposers: Fungi are Earth’s primary recyclers. They break down dead wood, leaves, and animal carcasses, returning vital nutrients back into the soil.

• Symbiotic Partnerships: Many fungi form mutually beneficial relationships with other organisms. For instance, mycorrhizal fungi attach to plant roots, vastly expanding the plant’s ability to absorb water and minerals in exchange for sugars produced via photosynthesis.

• Human Uses and Impacts: Fungi are essential in baking and brewing (yeasts), medicine (antibiotics like penicillin), and food (edible mushrooms). However, they can also cause plant diseases and human infections (such as ringworm or athlete’s foot).