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FUNGIWow! Fungi plant growth - The
Private Life of Plants - David Attenborough - BBC wildlife -
YouTube
Fungi• non-motile
• heterotrophs
• defining characteristic of fungi is mode of getting food: “extracellular digestion and absorption”
• secrete digestive enzymes
into the environment, then absorb the nutrients released by those enzymes.
• most are decomposers: live on decaying organisms.
• some are parasites: extract food from living organisms
Kingdom Fungi
• fungi were once members of the plant kingdom
• some similarities include:
• cells are eukaryotic (true nucleus with many organelles).• most are stationary, anchored in the soil• reproduction can be asexual, sexual or both.
• However, fungi have evolved in a different direction than plants:
Plants FungiHave one nucleus per cell Often have many nuclei per cell
autotrophs (have chlorophyll) heterotrophs
Starch is the main storage molecule
Have few or no storage molecules
Most have roots No roots
Cellulose in cell walls Chitin in cell walls (like insects)
Most reproduce by seed None reproduce by seed
Fungi Structure & Function
made of hyphae: tiny threads of cytoplasm surrounded by plasma membrane & covered by cell wall
cell walls made of chitin (same as insect shells)
hyphae interwoven to creately mycelium: mesh of microscopic branching hyphae that are usually on or just below the surface of the ground.
the visible parts (stem and cap)of the fungi are the fruiting body (reproductive parts)
Fungal Feeding vast network of
mycelium underground form mycorrhizae
forms a symbiotic relationship with plant roots
gains sugars, starches, protiens and lipids from plant roots
provides plant with extension of root to get water and minerals
Fungi Reproduction reproduce asexually when a
piece of the hyphae breaks off or by releasing spores.
spores are haploid cells (have a single set of chromosomes)
spores are able to withstand unfavourable conditions and are carried by wind to germinate in other locations.
fungi can also reproduce sexually when opposite haploid hyphae grow towards each other and fuse to form a diploid zygospore (which has 2 sets of chromosomes).
Planet Wild - Fungi - YouTube
Negative Roles of Fungus:
• crop parasites (corn smut) – fungi cause a lot of damage to crops each year
• foot fungus – athletes foot caused by Trichyphyton sp
• chytrid – killing frogs
•Frogs: The Thin Green Line - Video: Full Episode - Amphibian Extinction - Chytrid Fungus | Nature | PBS
Positive Roles of Fungus:
• decomposers (or recyclers) of nutrients in ecosystems.
• vital component of many foods (blue cheese, mushrooms, baking and brewing (yeast).
• antibiotics (penicillin)
• Lichens act as air quality monitors by absorbing toxins in the soil and the air.
Yeast
Major Phyla of Fungi
Phylum Reproductive Structure
Examples
Zygomycota
(common molds)
Zygospores that contain sexual spores
Black bread mold
Pilobolus
Basidiomycota
(club fungi)
Club-shaped cell (basidium) contains sexual spores
Mushrooms, puffballs, shelf fungi
Ascomycota
(sac fungi)
Sacs called asci that contain sexual spores
Yeasts, truffles, morels
Chytrids Fungi with flagellated spores
chytrids
Zygomycetes
• Zygomycetes form a diploid spore (think “zygote”) that undergoes meiosis after germination. Zygomycetes also have asexual, haploid spores.
• Bread mold is a common zygomycete
• Another important zygomycete group is the mycchorrhyzae, fungi that infect the roots of most plants. These fungi have a symbiotic relationship with the plants: the fungi gather nutrients form the soil as an extension of the roots, and the plant supplies nutrients from photosynthesis.
Basidomycetes: Club Fungi
• Mushrooms are the most common club fungi. Others include rusts and smuts that harm crop plants.
• The visible mushroom is merely a fruiting body. The bulk of the organism is underground, a mat of hyphae (strands) called a mycellium that can be quite large. One example in Oregon covers 2200 acres (3 ½ square miles), to a depth of 3 feet, and it is at least 2400 years old.
Ascomycetes• Ascomycetes are sac fungi:
they produce spores in sacs.
• Truffles and morels are good examples of ascomycetes: they taste good!
• Penicillium, the mold that gave penicillin, the first antibiotic, is an ascomycete. Pennicillium also gives flavor to certain cheeses.
• Sac fungi also include some important single celled yeasts. Saccharomyces cerevesiae is used to make bread rise and also to ferment beer and wine. Candida albicans produces the common human yeast infections.
Zygomycota Basidiomycota Ascomycota
Chytrid