Ecology of Fungi

Many fungi are saprobes – food from decaying organic matter All fungi are heterotrophs

Fungi as Decomposers –Fungi (and bacteria) are the principal decomposers of ecosystems and keep ecosystems stocked with the inorganic nutrients necessary for plant growth. –Without decomposers, carbon, nitrogen, and other elements would accumulate in nonliving organic matter. Found nearly everywhere

Fungi as Parasites (continued) Human Diseases: –Pathogenic (disease causing) –Mostly deuteromycetes –Examples: Athlete’s Foot*; Ringworm; Yeast, Candida albicans, can cause mouth infections *In Athlete’s Foot, mycelium forms directly in outer skin layers, produces sore where spores spread easily from person to person

Fungi as Parasites Plant Diseases: –Loss of 15% of crops in temperate regions, and 50% in tropical regions –Wheat Rust – Basidiomycete – caused great plagues in 1930s (the Great Depression). Wheat Rust has a complex life cycle – requires the barberry plant before the wheat fields

Fungi as Parasites (continued) Animal Diseases: –Cordyceps – infects grasshoppers in rainforests in Costa Rica –Hyphae and mycelium digest insect and then sprout fruiting bodies out of insects

Commercial Uses of Fungi Bread and Alcohol – –Yeast, Saccharomyces, to grow yeast, you need nutrients and NO oxygen (O 2 ); the by- products of yeast growth are CO 2 and alcohol for fuel or drinks Food – Basidiomycetes – mushrooms Medicines/antiobiotics – penicillin (deuteromycota)

Symbiotic Relationships Lichens - –Not single organisms – they are a symbiotic relationship/association between a fungus and a photosynthetic organism – cyanobacteria or green algae –Algae provide food by photosynthesis; fungus provides water and minerals –First organism to enter a barren environment – assist with soil formation

Symbiotic Relationships (continued) Mycorrhizae – –Associations between fungus and plant roots –80% of plant species form mycorrhizae relationships –Hyphae of fungi aid plants in absorbing water and minerals –Plants provide fungi with products of photosynthesis