Post on 15-Dec-2015
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).