I. Fungi A.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, athlete’s foot)

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.

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.

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

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.

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.

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

Mycorrhizae