The Kingdom Fungi

What is a Fungus?

• Fungi are eukaryotic heterotrophs • Decomposers known as saprophytes • Cell walls made up of chitin • Some are parasites – Ex. Athlete’s Foot, Ringworm • Some are symbionts – Ex. Lichen • Fungi do not ingest food, they release enzymes and absorb nutrients

Structure and Function of Fungi

• All fungi are multicellular (except yeasts, which are unicellular) • Composed of tiny filaments called hyphae. Each hyphae is only one cell thick.

• Many hyphae tangled together into a thick mass called a mycelium. Mycelium absorbs nutrients for fungi • What you see above ground is the fruiting body, or reproductive structure of fungi. Fruiting body develops from mycelium underground.

– Why is the fruiting body above ground?

– Why is the mycelium underground?

The Structure of a Mushroom

Hyphae Fruiting body “Gills” would be located under here – where spores can be found Mycelium This is a typical Club fungi

Reproduction and Spreading of Fungi • Most fungi reproduce both sexually and asexually • Asexually – hyphae break off and grow on their own or scatter spores • Some fungi lure animals with scent to help them disperse their spores over distances • Fragmentation, spores, conjugation

Classification of Fungi

• Classified according to structures and method of reproduction • Four phyla: – Zygomycota – Common Molds – Ascomycota – Sac Fungi – Basidiomycota – Club Fungi – Deuteromycota – Imperfect Fungi

Phylum Zygomycota – Common Molds - Zygomycetes • Terrestrial • Hyphae lack cross walls – they look like one big cell Nuclei Cell wall Cytoplasm Cross wall Nuclei Cytoplasm

Hyphae With Cross Walls

Cell wall

Hyphae Without Cross Walls

Phylum Zygomycota – Common Molds - Zygomycetes • Example: Black bread mold,

Rhizopus stolonifer

• Black bread mold has root-like hyphae that penetrates the surface of bread – called rhizoids

Sexual and Asexual Reproduction of

Rhizopus

Spores (N) Sporangiophore

Asexual Reproduction

Sporangium Zygospore (2N)

FERTILIZATION

Gametangia

MEIOSIS

Sporangium Spores (N) Zygospore (2N) Stolons + Mating type (N) - Mating type (N) Rhizoids

Sexual Reproduction

Diploid Haploid

Phylum Ascomycota – Sac Fungi • Largest phylum – 30,000 species • Nuclei separated by cross walls • Named for ascus – reproductive structure containing spores • Examples: Yeast (unicellular), cup fungi Nuclei Cell wall Cytoplasm Cross wall Nuclei Cytoplasm

Hyphae With Cross Walls

Cell wall

Hyphae Without Cross Walls

Sexual and Asexual Reproduction of an Ascomycete Fruiting body (N + N) Hyphae (N + N) Ascus (N + N) Diploid Haploid Zygote (2N) Gametangia

HYPHAE FUSE

Hyphae (N) + Mating type (N) - Mating type (N) Asci

Sexual Reproduction FERTILIZATION

Conidia (N) Conidiophore Hypha (N)

Asexual Reproduction

Hypha (N) Ascus 8 Ascospores (N)

Examples of Phylum Ascomycota Yeast

Aleuria aurantia Cookeina colensoi

Phylum Basidiomycota – Fungi Club • Gets name from specialized reproduction structure resembling a club, called basidium – found on the underside of mushroom cap in the gills • One mushroom may produce 1 billion spores • Some are edible, some are toxic • Examples: Mushrooms, toadstools • Most elaborate life cycle of all the fungi

Sexual and Asexual Reproduction of Basiomycete Fruiting body (N + N) Gills lined with basidia Button Cap Gills Stalk Base Secondary mycelium (N + N)

HYPHAE FUSE

Primary mycelium (N) - Mating type (N) Zygote (2N) Basidia (N + N)

FERTILIZATION

Haploid Diploid + Mating type (N) Basidiospores (N)

MEIOSIS

Orange Jelly Examples of Phylum Basidiomycota Pigskin Poison Puffball Fly Agaric Shelf Fungus Bird’s Nest Fungus Star Stinkhorn

Phylum Deuteromycota – Fungi Imperfect • Varied phylum • Not much known about fungi placed in this phylum • Example:

Penicillium

– antibiotics • Do not appear to have sexual reproduction

Examples of Phylum Deuteromycota

Penicillium notatum

Ringworm Athlete’s Foot

Zygomycota includes Common molds

Fungi

are divided into the phyla Ascomycota includes Sac fungi Basidiomycota Deuteromycota includes Club fungi includes Imperfect fungi