I. Fungi

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I. Fungi

• Characteristics
• Heterotrophs (feed off other organisms)
• Many fungi are saprobes (feed off of
• dead and decaying organisms)
• Some fungi are parasites (feed off of
• living organisms for example,
• athletes foot)

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I. Fungi

• B. Anatomy of Fungi
• Main body is a mesh (mycelium) made of
• many smaller units (hypha).
• Hypha is a single cell, surrounded by a cell
• wall of chitin.
• Mushroom is one example of a fruiting
• body, used for reproduction.

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I. Fungi

• C. Reproduction in Fungi
• Most hypae are haploid (n).
• When two hyphae join, they unite nuclei
• into one cell, which grows into
  fruiting
• body.
• Fruiting body (such as mushrooms)
• release spores.

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After nuclear fusion, the club-shaped structure
(now 2n) will produce and bear haploid spores at
the four tips of the cell.
Diploid Stage
nuclear fusion
meiosis
Haploid Stage
spore (n)
Club-shaped structures having two nuclei (n n)
form at the margin of each gill.
Spores are released.
hypha in mycelium
Each germinating spore gives rise to a hypha that
grows and becomes a branching mycelium.
gills
cap
stalk
hypha
After cytoplasmic fusion, a dikaryotic (n n)
mycelium gives rise to spore-bearing bodies
(e.g., mushrooms).
cytoplasmic fusion
Fig. 24.4, p. 395
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I. Fungi

• D. Fungi Diversity
• 1. Club Fungi (Basidiomycetes)
• Produce common mushrooms.
• 2. Zygomycetes Includes bread molds.
• 3. Sac Fungi (Ascomycetes) Include
• organisms such as yeast and truffles.

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I. Fungi

• E. Value of Fungi
• Decompsers in nature
• Mycorrhizae Fungi and Plant grow
• together fungi breaks down material in
• soil, releasing nutrients while plant
• provides food to fungi.
• Lichen Fungi and Algae growing together.
• Fungi breaks down rock or soil, while
  algae
• provides photosynthesis.

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dispersal fragment (cells of mycobiont and of
photobiont)
cortex (outer layer of mycobiont)
photobionts
medulla (inner layer of loosley woven hyphae)
cortex
Fig. 24.9a, p. 378
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Mycorrhizae
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Mycorrhizae