Fungi The Kingdom Fungi Fungi are eukaryotic heterotrophs

Fungi

The Kingdom Fungi • Fungi are eukaryotic heterotrophs that have cell walls – Cell walls made of chitin—complex carbohydrate found in insects’ exoskeletons • Structure and Function – Multicellular (except yeasts) – Composed of hyphae—thin filaments one cell thick – Cross walls—cytoplasm and nuclei can move through openings – Without cross walls—contain many nuclei – Secrete enzymes to digest food outside their bodies and absorb the nutrients

Hyphae Structure Nuclei Cell wall Cytoplasm Cross wall Cytoplasm Hyphae With Cross Walls Nuclei Cell wall Hyphae Without Cross Walls

The Kingdom Fungi – Mycelium • many hyphae tangled together into a thick mass that composes the bodies of multicellular fungi • Well suited to absorb food because it has a large surface area – Fruiting body—reproductive structure growing from the mycelium (ex: mushroom) – Sexual Reproduction- Plasmogamy, Karyogamy, Meiosis

The Kingdom Fungi • Reproduction – Sexually • Two different mating types--+ (plus) and – (minus) • + and – fuse together, grow, form a diploid zygote nucleus, produce haploid spores – Asexually • Cells or hyphae break off from a fungus and begin to grow on their own • Some produce spores in sporangia which are found at the tips of specialized hyphae called sporangiophores

The Kingdom Fungi • How Fungi Spread – Fungal spores • Scatter easily in the wind • Must land in favorable environment – Temperature – Moisture – Food • Some are specialized to lure animals, flies – Disperse spores over long distances

Classification of Fungi • Phycomycetes ( Common Molds) – Structure and Function of Bread Mold • Rhizoids—rootlike hyphae that penetrate the bread’s surface • Stolons—stemlike hyphae that run along the surface of the bread • Sporangiophore—hyphae that push up into the air and form sporangia at their tips • Aseptate, Coenocytic without cross-walls

Ascomycetes Yeasts, Aspergillus, Penicillium, Neurospora • • • Unicellular fungi Ascomycetes—baking and brewing Budding—process of asexual reproduction – conidia Sexual Reproduction - Ascospores Alcoholic fermentation to obtain energy – Byproducts—carbon dioxide and alcohol

Ascomycota

Classification of Fungi • The Club Fungi Agaricus (muschroom) Puccinia ( Rust Fungi) – Basidiomycota—basidium (resembles a club) – Hyphae are branched and septate – Dikaryon stage seen ( n + n )

Basidiomycota

– Diversity of Club Fungi • • • Mushrooms Shelf fungi Puffballs Earthstars Jelly fungi Rusts – Edible and Inedible Mushrooms • Almost identical • Some inedible can cause severe illness or death

Deuteromycetes • The Imperfect Fungi – Deutoeromycota • • Do not appear to have sexual reproduction Most resemble ascomycetes Branched and Septate Trichoderma, Alternaria, Colletotrichum

Deutoeromycota

Ecology of Fungi • All Fungi Are Heterotrophs – Saprobes • Organisms that obtain food from decaying organic matter – Parasites – Symbionts – Capture live animals • Pleurotus ostreatus • Lives on the sides of trees and trap worms to digest them

Ecology of Fungi • Fungi as Decomposers – Maintain equilibrium in nearly every ecosystem by recycling nutrients – Release digestive enzymes that break down organic material into simple molecules which diffuse into the fungus

Ecology of Fungi • Fungi as Parasites Corn smut – Cause serious plant and animal diseases and a few cause diseases in humans – Plant Diseases Plant mildew • Smuts, mildews, rusts Spruce rust

Ecology of Fungi • Symbiotic Relationships – Mutualistic (both benefit) – Lichens • Fungus and an alga or a cyanobacterium or both • Live mostly on bare rock and in places that most other organisms cannot live • Break down rock into soil • Autotroph makes food, fungus absorbs water and nutrients and serves as an anchor

Ecology of Fungi – Mycorrhizae • Plant roots and fungi • Plant roots provide energy and fungus provides a large surface area for more absorption of water and minerals