Chapter 22 Fungi Evolution and Diversity PDF

Preview

Summary

Chapter 22 lecture notes...

Description

Chapter 22: Fungi Evolution and Diversity  

Chyten: main component of fungus (human: lycogen, plant: cellulose) Fungi + cyanobacteria = lichen

Characteristics   

  

Supergroup opisthokonta Includes over 80,000 species, mostly multicellular with chitin in cell wall Common mode of nutrition -Heterotrophic -Saprotrophic: cells release digestive enzymes that break down and absorb resultant nutrient molecules Protists evolved 1.5 BYA -Plants, animals, and fungi trace ancestry back to protists Molecular data shows us that animals and fungi show more recent common ancestor than either do to plants Flagellated, unicellular protists (choanoflagellate) thought to be the common ancestor

Evolutionary Characteristics   



Anatomy doesn’t lend itself to becoming fossilized Estimated that fungi evolved earlier than first fossil- 460 MYA Mycorrhizae are evident in plant fossils- mutualistic relationships betwwen soil fungi and roots of most plants -Give plants absorptive surface area -Ecto and endo mycorrhize -Endo- cell wall -Ecto- grow between cell wall Fungi are different because they are saprotrophic

Fungi Groups (6 total) Zygomycota    

 

Causes black bread mold Produce zygospores Asexual and sexual life cycle 3 types of hyphae -Stolons: -Rhizoids: embed into bread in bread mold -Sporangium: Break down dead material Ready to release spores  released by air currents

Ascomycota              

Sac fungi- 64,000 known species Molds can be helpful Aspergillus: green molds to produce soy sauce, citric and gallic acids Saccharomyces cerevisiae: beer and wine Penicillin: bleu, brie, Roquefort, fancy cheeses Candida albicans: yeast, thrush- forms when balance of candida and other microorganisms normally found on body is disturbed Digest resistant material Cause many plant diseases Morels and truffles Talaromyces: formerly penicillium, source of penicillin Aspergillus and Candida, serious infections Asexual reproduction Be able to tell what organism is in ascomycota- thrush, ex Bud scars- 1 bud scar, 1 year

Basidiomycota       

Edible mushrooms (shitake, portabella) Reproduce through basidiospores Basidiocarp: fruiting body (i.e. mushrooms) Toadstools, mushrooms, shelf fungi (trunks of tree), birds nest, stinkhorns, puffballs 75 poisonous – “death cap” mushroom Smuts and rusts- typically affects corn crops -Parasitize Death angel mushroom poison inhibits RNA polymerase, leading to liver and kidney damage

-Study table 22.1: Features of Fungi Phyla Structure of Fungi      

Body (thallus) of most fungi is multicellular mycelium (yeasts are unicellular) Cell walls of chitin, polymer of glucose that is organized into microfibrils Excess food stored as glycogen as in animals Mycelia: mold, decaying Ascus: fingerlike sac that develops during sexual reproduction -Could be surrounded and protected by sterile hyphae within a fruiting body called ascocarp

Reproduction  

 

Both sexual and asexual reproduction 3 stages: 1. Haploid hyphae: n 2. Dikaryotic stage (two nuclei): nucleus hangs out and don’t fuse right away 3. Diploid zygote: fuse together, now they are 2n Asexual reproduction involves production of windblown spores -A large mushroom can produce billions of spores in a few days Unicellular yeast reproduce asexually by budding (small cell forms and gets pinched off as it grows)

Symbiotic Relationships  

Fungal parasites of plants exist through fungi Geomyces destructans: white nose syndrome on bats, infection wakes them up from hibernation and they starve to death...