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).