exam 3 (22) Flashcards
how many fungal species have been described
120,000 described taxonomically
hawksworth 1991 fungi estimation
estimation of total fungal species based on plant to fungal ratio British isles, US products, sweden, alpine sedge. all from high N lat. biomes no tropical locations used
fungal estimates based on soils
black spruce forests
Fungal:plant ratio is 17:1 based on forest soils from interior alaska. Estimates at least 6 million fungi species
global diversity and geography of SOIL fungi
Plant:Fungal species ratios
both highest at equator
decline in richness is steeper for plants in temperate and boreal regions
more F at high lat and more P closer to equator
where are the rest of the fungi?
- biodiversity hotspots (amazon in S am)
- little-explored habitats (lichens)
- cryptic species (morphologically same but genetically diff)
- existing reference collections (not named yet)
current best fungal richness estimate
2.2 to 3.8 million. hawkswort
Previous thought. 4 major fungal lineages
chytrids, zygos, ascos, basids
more than 6 fungal lineages
major clades based on molecular evidence
- microsporidians
- chytrids
- zygomycetes
- glomeromycetes
- ascomycetes
- basidiomycetes
microsporidians
1500 species
MONOphyletic
endocellular habitat (animal parisites)
microsporidians: ecology, growth form, septation
ecology: obligate symbionts (not freee living but live in cells)
growth form: unicellular
septation: absent
key features of microsporidians
no mitochondria
no chitin in cell walls (in endospores)
polar tube injection
famous microsporidian immuno-compromised
encephalitozoon
microsporidiosis: serious problem with immuno-compromised humans
shoots out and punctures cell with genetic material, makes more fungi
nosema
microsporidia
associated with colony collapse disorder
inc uptake
chytrids
800 species
POLYphyletic
chytrid: habitat, ecology, growth form, septation
habitat: primarily aquatic
ecology: free-living, symbionts
growth form: hyphal
septation: largely absent
key features chytrids
flagellated zoospores (ONE) presence of centrioles (more like animals)
amphibian decline
chytrids batrachochytrium dendrobadis colonizes skin layer where they respires and causes leisons. swelling from infection inhibits respiration tadpoles are reservoir Bd lives on keratin in mouth
cow rumen
neocallastix
chytrid
obligate (symbiosis) anaerobe - cow rumen
cow guts
cellulase production major part of break down of plant cell walls
breakdown grass - glucosis
chytrid life cycle
alternation of generation
2 multicellular stages like plants
Sporic meiosis
isomorphic (n and 2n look similar)
zygomycetes
1000 species
POLYphyletic
zygomycetes: habitat, ecology, growth form, septation, key feature
habitat: both terrestrial and aquatic
ecology: free-living and symbionts
growth form: hyphal and unicellular
septation: largely absent
key feature: zygospore (thick walled sexual spore)
bread and fruit mold
rhizopus
zygomycetes
key fermentative agent of tempeh from SE Asia
pathogen of insect
entomophthorales
zygomycetes
produces compounds that change insect behavior, causing them to climb onto higher surfaces for better spore dispersal
destroys back of insect to release sporangia
zygomycete life cycle
multicellular in N stage
zygotic meiosis
reproduces asexually for LONG time
