Fungi Chapter 31

Fungi - heterotrophs - eat by absorbing nutrients - by secreting enzymes to outside which digest food around them; fungi absorbs food. Fungi composed of hyphae - make up fungi’s mycelium (feeding network)

Fungi multicellular - hyphae divided by septa. Septa have pores to allow transfer of material from one to another. Parasitic fungi adapted to attack host by burrowing into host with haustoria.

Fungi can reproduce sexually or asexually. Spores produced and released from parent fungi. Sexual reproduction - parent’s cytoplasm fuse together (plasmogamy). Haploid nuclei then fuse together (karyogamy)

Diversity Phylum Chytridiomycota – chytrids - aquatic fungi that can be parasitic. Cell walls made of chitin - most primitive fungi; probably evolved from protists that had flagella.

Phylum Zygomycota –zygote fungi - mostly terrestrial; can form mutualistic relationships with plants (mycorrhizae). Unfavorable conditions - can form resistant spores to wait until conditions are favorable before germination.

Phylum Ascomycota – sac fungi - found everywhere. Most live in mutualistic relationship with algae - lichen. Fungi keep sexual stage in fruiting body - asocarp.

Phylum Basidiomycota – club fungi - mushrooms. Reproduce by fruiting bodies - basidiocarps. Asexual reproduction very uncommon.

Other types Molds fast growing, asexual fungi. Mold refers to early asexual stage of fungus not classified into phylum. Yeasts reproduce asexually - fungus that inhabits water and is unicellular.

Lichen result of relationship between algae and fungus. Alga gives fungus food; fungus gives alga place to grow and protection. Mycorrhizae result of relationship between plant roots and fungi. Help increase surface area for absorption to take place.

Fungal impacts Fungi important to ecosystem - help to break down inorganic nutrients that plants can use. Percentage of fungi parasitic and contribute to damaging crops and various plant species. Can also cause skin infections in humans.

Fungi used for food (mushrooms, cheeses), components of soda, antibiotics, and in bread making and brewing (yeasts).