Lecture 9 Flashcards
What is the largest organisms by area?
fungus
Humongous Fungus
invades roots; through DNA fingerprinting has been determined one organisms spans over 1000 hectors
Fungus as “Friend”
more benefits from fungus than harm
break down lignin and cellulose
Fungi
- absorptive heterotroph
- decomposer (saprobes, saprotrophs)
- cell wall of chitin (poly-glucosamine) and glucans (polysaccharide)
absorptive heterotroph
don’t synthesize, release enzymes into the environment that partially digests organic matter then draw nutrients in across cell wall
saprobes
feed on dead organic matter
chitin
poly-glucosamine
glucan
polysaccharide
Produce spores - Fungus
single cell that yields new organisms, disperse from parent and can live out unfavourable condition
Fungus - similarities to plants and animals (3)
- multicellular (unicellular yeast budding)
- terrestrial
- produce spores
Fungus - Filamentous (5)
- provide large surface area
- divided into cell-like components by porous septae
- cytoplasm is continuous
hyphae - long branched filaments
mycelium - tangled mass of hyphae
mycelia (4)
mycelium (dense hyphae) mycelium of absorptive structure (spaced hyphae, to absorb more nutrients) fruiting body (capable of producing spores)
Stucture
most fungus is underground
-above ground is a fruiting body
fruiting bodies
- only small portion of biomass
- reproduction
- fairy ring
symbiotic
commensal (+/0)
mutualistic (+/+)
parasitic (+/-)
saprophytic
decomposer
predatory
create loops as noose that tightens down on nematode that accidentally swam through it, then secretes enzymes into nematode for digestion
How is fungus important to plant’s growth and survival?
mycorrhiza (mutualistic relationship with plant root)
fungus receives carb
plant receives minerals
plant grows bigger if with fungus
endomycorrhiza
within plant root and cell(80%)
ectomycorrhiza
hyphae extends into soil and cell wall but not cells
Fungal hyphae in stem (When?)
- long history
- older than vascular plants
- Devonian period (385 MYA)
Lichen with fungus
fungus + cyanbacterium/green algae
-given protection from desiccation (dryness) & algae provides photosynthetic products to fungus
Lichen
- pioneer species in newly formed habitats
- sensitive to poison air
- breaks down rock to form soil
- tolerate extreme climates
- food for tundra
- diverse
Lichen mutualistic relationship with leaf cutter ant
- feed fungal colony that breaks down cellulose
- hyphae feed to any
- ants provide protection
Fungi - Pathogens (6)
- ring worms
- ergot in rye
- athlete’s foot
- thrush
- tar spots
- corn smut
fungal infection are harder to treat than bacteria coz it’s closer in relationship with animal
spores of fungus
unicellular reproductive structure; asesually/ sexually
mushroom gill
basidia - spores
fungus - asexually (4)
- budding
- fission
- conidia (spores at the end of hyphae)
- spores in sporangia
disperse by air/water (puffball)
Phylogeny of Fungi
- flourish by Permian period
- closely related to animals than plants
- domain of botanists for 100 years
- 100,000 species
Chytrid and Zygomecetes
potentially arises multiple times or some traits are lost, phylogeny is not clear
Basidiomycota
mushrooms
yeast
- unicellular
- have plasmid (good for model for genetics)
- belong to zygomecetes, basidiomycota, ascomycota
microsporidia
- relationship to other eukaryotes have puzzled taxonomists for decades
- Among smallest eukaryotic organisms
- Unicellular
- Lack mitochondria, but instead have mitosomes (derived from mitochondria, but lack DNA)
- Obligate intracellular parasites
Chytrides (paraphyletic)
- aquatic
- 1000 species
- flagellated gametes and spores (only group with motile stage)
- unicellular and multicellular stage
- saprobic, mutualistic, parasitic (affected frog epidermis, causing global decline of amphibians)
- only fungi with alternating life cycle
Zygomycota
- saprobic, parasitic, terrestrial
- > 1000 species
- spores contained in sporangia astop specialized hyphae
Zygomycota - reproduction cycle
- haplontic life cycle
- Zygosporangium - resistant spore
- dikaryotic cycle: cytoplasm fuse but not nuclei (plasmogamy) leads to this phase then nuclei fuse in karyogamy
Glomeromycota
- > 200 species
- terrestrial
- form arbuscular endomycorrhizae
- transfer phosphorus to plants
- no known sexual stage
Basidiomycota (Club Fungi)
- terrestrial, aquatic
- fruiting bodies = basidiocraps
- 30,000 species
- saprobes
- ectomycorrhizae
- only group able to digest lignin
- rusts & smuts
Basidiomycota (Club Fungi)
- diploid stage very short
- cytoplasm and nuclei fusion not parallel
Ascomycota (Sac Fungi)
- terrestrial, aquatic
- fruiting bodies with sacs: morels, truffles
- 70,000
- conidia produced asexually in specialized hyphae
- karyogamy before plasmogamy
- Pseudogymnoascus destructans: cold-loving; important to conservation
- fungal infection on bats: white nose syndrome
