Fungi

Fungi are living things that are neither plants nor animals. They form their own kingdom in the tree of life. Mushrooms, molds, yeasts, and the fuzz on old bread are all fungi. Scientists have named about 150,000 kinds, but they think millions more are still waiting to be found.

Fungi do not make their own food the way plants do. They cannot do photosynthesis because they have no chlorophyll. Instead, fungi get their food by breaking down other living or dead things. Most fungi grow long, thin threads called hyphae. These threads spread out through soil, wood, or a piece of fruit. The hyphae release special chemicals that dissolve the food around them. Then the fungus soaks the food up, almost like drinking.

Oddly, fungi are more closely related to animals than to plants. Their cells share chemistry that plant cells do not have. Scientists once grouped fungi with plants, but better tools showed that fungi belong on their own branch.

A mushroom is only a small part of a fungus. The rest lives hidden underground or inside wood. The mushroom is the fruiting body, the part that makes spores. Spores are tiny cells, smaller than grains of dust, that float away on the wind. When a spore lands in a good spot, it grows a new network of hyphae. A single mushroom can release billions of spores in a few days.

Fungi do jobs that no other living thing can do as well. They are nature's cleanup crew. When a tree falls in the forest, fungi break it down into soil. Without fungi, dead leaves, logs, and animals would pile up everywhere. Many plants also team up with fungi underground. The fungi bring water and minerals to the plant roots, and the plant shares sugar in return. Forests would not grow the same way without these partnerships.

People use fungi every day. Yeast makes bread rise and turns grape juice into wine. Mold gives blue cheese its blue streaks. A mold called Penicillium gave the world penicillin, the first antibiotic, which has saved millions of lives since 1928. Some fungi are dangerous too. Athlete's foot, ringworm, and many plant diseases are caused by fungi.

Fungi also hold mysteries. Scientists still debate how some fungi communicate through their underground networks, and whether the pulses of chemicals they pass through the soil count as a kind of signal between plants.