Lecture 7 Fungi Flashcards
Fungi is
one of 3 major lineages of large terrestrial Eukaryotes.
It has 110000 named species, few fossils, thus hard to study. Yeasts and chytrids are unicellular.
How does taxonomy work for fungi
Based on reproductive structures & DNA. Divided into Chytrids, Zygomycetes, Basidiomycetes, Ascomycetes
When is the first fungi (aquatic) and when did fungi colonize land
800-1000 mya; 500 mya.
Characteristics of fungi (5)
Symbiotic (partners/pathogens), uni/multi-cellular, ubiquitous, decomposer, of human uses.
Largest organism in the world is
fungi Armillaria Ostoyae.
Difference between yeast & bacteria (2)
Bacteria are prokaryotes (no membrane bound nucleus) while Fungi are eukaryotes (nucleus).
Bacteria cell walls are of peptidoglycan while fungi are of chitin.
4 defining features/impacts of fungi
Structure, Nutrition, Reproduction, Dispersal
Describe the structure of fungi (6).
Single celled or filaments (multicellular).
Cell walls of chitin (same as insects).
No complex transport system.
All single-celled species are not monophyletic. Yeasts are unicellular.
Mycelium is made of hyphae (long thin filaments) and can pack to form muchrooms
Hyphae are separated by cross-walls called septa, with pores for passsage of nutrients and nuclei.
Describe the nutrition of fungi (7)
Fungi absorb food directly from surroundings (heterotrophs).
Thin hyphae lead to mastery of absorbing.
Fungi secret digestive enzymes externally (heterotrophs). Can be saprophytes (eat dead stuff) or symbionts (get fed by others unintentionally).
Plant lignin & cellulose are most abundant molecules. Fungi are first and most effective at decomposing it.
Lichens are symbiosis of fungi & algae/cyanobacteria, 6% of earth surface.
Mycorrhizae are plant-fungal symbiosis, 80% of vascular plants use fungi b/c hyphae increases SA of root system for absorption.
Chytrid fungi: pathogens on amphibians.
Describe the asexual reproduction of fungi (2)
Many reproduce in multiple ways (sexual, asexual, diverse) (1n haploid, 2n diploid).
Asexual reproduction:
Simplest form=fragmentation (break apart),
OR Complex=vegetative spores during haploid phase
Describe the sexual reproduction of fungi (6)
Reproductive structures observable.
Individuals fuse mycelia to initiate plasmogamy to produce dikaryotic mycelium (two 1n nuclei in one cell), can last long.
Produce mushroom with gills.
1n fuse (karyogamy)- one cell with 2n nuclei
Then meiosis (2n-1n)-spores
- Mushrooms are like fruits. They are predominantly for dispersal
Describe the dispersal of fungi (4)
Spores are tough & specialized for dispersal, can tolerate dryness. Small size for airborne dispersal.
Ejection mechanisms: puffballs
OR animal dispersers: stinkhorns
OR cordyceps creates zombies
Fungi impacts on human (6)
Edible mushrooms
Fermentation: break down sugars into alcohols & CO2. Used in alcohols from grains and fruits, bread, soy sauce, and cheese.
Mycotoxins (penicillin)
Control insect pests
Bioremediation (white rot fungus devours lignin)
Model organisms of biology (yeast)
