All Living organisms are organised into large groups called Kingdoms. Fungi were originally placed in the Plant Kingdom then, scientists learned that fungi were more closely related to animals than to plants. The scientists decided that fungi were not sufficiently similar to animals to be placed in the animal kingdom and so today fungi have their own Kingdom - the Fungal Kingdom.

The fungal kingdom is largely hidden from our view and we usually only see the "fruit" of a fungus. The living body of a fungus is called a mycelium and is made up of a branching network of filaments known as hyphae. Fungal mycelia are usually hidden in a food source like wood and we only know they are there when they develop mushrooms or other fruiting bodies. Some fungi only produce microscopic fruiting bodies and we never notice them.

Fungi feed by absorbing nutrients from the organic material that they live in. They digest their food before they absorb it by secreting acids and enzymes. Different fungi have evolved to live on various types of organic matter, some live on plants (Phytopthora infestans - the potato blight fungus) some on animals (the athlete's foot fungus) and some even live on insects (Cordyceps australis).