Kingdom Fungi

21-1: What is Fungi? Fungi are organisms that are eukaryotic and heterotrophic. Most are multicellular and have cell walls made of chitin. Fungi do not ingest their food like animals…. They absorb food that is digested outside of their bodies. Example: absorbing nutrients from decaying matter in soil.

Structure of Fungi Multicellular fungi are composed of thin filaments called hyphae. Each hypha is one cell thick and may or may not contain cross walls that cytoplasm and nuclei can move through. Many hypha tangled together form the mycelium that are well suited to absorb nutrients with a large surface area. The fruiting body is the reproductive structure that grows above ground. (what we call “mushrooms”) A fairy ring is a group of fruiting bodies that sprout at the edges of a mycelium.      

Cross walls Fairy Ring

Reproduction in Fungi Most fungi reproduce asexually and sexually. Asexually- hyphae break off and grow on their own, or produce spores that scatter and grow on their own. Sexually- A “plus” and a “minus” gamete meet, 1) fuse, 2) grow and develop, 3)form a diploid zygote that enters meiosis to produce haploid spores. Fungus spreads through spores landing in favorable conditions to reproduce.

21-2: Classifications of Fungi There are four classifications of Fungi: Common Molds 2) Sac Fungi 3) Club Fungi 4) Imperfect Fungi

Common Molds Examples: Black mold, Bread mold Molds are small organisms that grow in moist areas. They are decomposers. Molds may reproduce sexually or asexually. They develop fruiting bodies and release spores that may lie dormant for a long period of time.

Sac Fungi Examples: truffels, mildew, morels, cup fungi Sac fungi are both decomposers and parasites. They produce spores in small sacs called asci. Reproduce both sexually and asexually. Yeast is the only unicellular fungi and it belongs to the sac fungi group.

Truffles are round, warty, fungi that are irregular in shape Truffles are round, warty, fungi that are irregular in shape. They vary from the size of a walnut to that of a man's fist. Since the times of the Greeks and Romans these fungi have been used in Europe as delicacies, as aphrodisiacs, and as medicines. They are among the most expensive of the world's natural foods, often commanding as much as $250 to $450 per pound. Truffles are harvested in Europe with the aid of female pigs or truffle dogs, which are able to detect the strong smell of mature truffles underneath the surface of the ground. The female pig becomes excited when she sniffs a chemical that is similar to the male swine sex attractant. The use of dogs to find truffles is also and option.

Club Fungi Examples: Mushrooms, shelf fungi, puffballs Club fungi are both decomposers and parasites Club fungi reproduction is considered both sexual and asexual. Club fungi produce spores in cells called basidia found in the gills.

Imperfect Fungi Regarded as imperfect because their reproduction method is totally asexual. Members are not closely related and are not necessarily similar in structure or appearance. Most are parasitic like the fungus that causes ringworm and athlete’s foot. The fungus that produces penicillin is an Imperfect Fungi.

Fungi are an important part of nearly all ecosystems. 21-3: Ecology of Fungi Fungi are an important part of nearly all ecosystems. Fungi can be: Saprobes 2) Parasites 3) Symbionts (decomposers)

Fungi as Decomposers Fungi play an essential role as they recycle nutrients by breaking down the bodies and wastes of other organisms. Example: most mushrooms. Fungi as Parasites Parasitic fungi cause disease in plants, animals, and humans. Example: ringworm Fungi as Symbionts Fungi can form a relationship in which both partners benefit. Example: lichen

Lichens Lichens are mutualistic symbiotic organisms. They have a fungus and an algae portion. The algae provide the food while the fungus provides an anchor and water. Lichens can grow anywhere and often reclaim areas after hazards.