Topic 18 Flashcards
Kingdom Fungi
Opisthokonts clade closely relating to plants, and the second most diverse group of eukaryots
Common Fungi Structural Features
- Hyphae and mycelium: long, thread-like filaments that form a network which increases surface area for nutrient absorption
- Chitinous cell wall: cell walls made of chitin, a strong, flexible carbohydrate that provides structural support and protection
Key Functional Fungi Characteristics
- Absorptive nutrition: fungi are absorptive chemoheterotrophs that absorb nutrients directly from their environment
- Spore Production: reproduce by producing spores which can be generated through mitosis or meiosis
Are fungi mobie?
No. They are non-motile and use growth to find and acquire nutrients in their environment
Hyphae
Cylindrical, branched, multicellular filaments that fungi have to absorb nutrients
Mucelium
Groups of hyphae
Benefits of Fungal Body Structural
Multicellular hyphal morphology enhances nutrient absorption by maximizing its surface area-to-volume ratio to secrete enzymes more efficient
Coenocytic Fungi
Earliest fungal lineages that exhibition coenocytic structure, lacking septa or dividing walls within their hyphae, but have a continuous cytoplasmic mass with thousands of nuclei
Septate fungi
Later evolving fungi with nuclear divisions called septa (Cross-walls) that divide the cytoplasm into separate cells
How do fungi reproduce?
Fungi reproduce by producing numerous spores asexually through mitosis or sexually by cell fusion and meiosis.
Fungal mycelia are haploid (1n) that produce haploid (1n) spores that grow to produce hyphae
Plasmogamy
the merging of cytoplasm from two parental mycelia, initiating the process of sexual reproduction in fungi
What is the basal fungi lineage
Clade Opisthosporidia consisting of two sister groups: Cyrptomycetes and Microsporidians
Cryptomycetes
A group in the basal fungi lineage that are found in marine, freshwater, and soil environments
Unicellular, have flagellated spores, and lack chitinous cell walls. Many are parasites of protists and other fungi
Microsporidians
Group in the basal fungi lineage that are spore-forming, unicellular parasites that infect insects via an infection organelle.
Lack flagellated spores but have chitin-rich cell walls
Chytrids
A clade of fungi that free-living unicellular decomposers that are often mutualists but some are parasitic
Zoopagomycetes
A clade of fungi with low diversity and chitinous cell walls, coenocytic filamentous hyphae, and reproduce asexually with zygosporangium that can survive unfavourable conditions
Typically parasites of other fungi, soil microbes, or animals
Mucoromycetes
Fast-growing decomposers (moulds) of plant tissues, parasites or pathogens of plants that are mutualists that reproduce sexually with the formation of zygosporangia
Includes glomeromycetes that have a mutualistic relationship between fungi and plant roots
Dikarya fungi
Most fungi belong to this subkingdom characterized by the formation of septate hyphae and the development of dikaryotic hyphae
Two clades: ascomycetes and basidomycetes
Ascomycetes
Clade of Dikarya that exhibit a brief dikaryotic stage, with plasmogamy and karyogamy occuring in relatively rapid succession
Basidiomycetes
Clade of Dikarya that maintain a prolonged dikaryotic phases, where dikaryotic hyhae frequently dominate in mycelium structure
Ecological Roles of Fungi
Decomposers, Mutualists, Pathogens
