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Kingdom Fungi Common Characteristics. Cells are eukaryotic All cells are surrounded by a cell wall containing chitin, not cellulose like plants Most are multicellular (yeast are single-celled) Reproduction is sexual and asexual, by producing spores They are heterotrophs
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Kingdom FungiCommon Characteristics • Cells are eukaryotic • All cells are surrounded by a cell wall containing chitin, not cellulose like plants • Most are multicellular (yeast are single-celled) • Reproduction is sexual and asexual, by producing spores • They are heterotrophs • Many are stationary and anchored in the soil, but without true roots
Some fungi are decomposers and recyclers. • Other fungi cause disease. (eg. Some moulds) • Some are parasitic (eg. Wheat rust) • Some form mutualistic relationships
FUNGI Some fungi are decomposers and recyclers. Other fungi cause disease. (eg. Some moulds) Some are parasitic (eg. Wheat rust) Some form symbiotic relationships (a relationship where both organisms benefit).
Fungal Structures • Fungi are composed of eukaryotic cells (have membranes and organelles) • They DO NOT have chloroplasts • The have long, thread-like microscopic cells called hyphae, which form masses called mycelia • The hyphae grow in and around a food source, secreting digestive enzymes and absorbing nutrients into the fungus.
Growth • Cells grow at the tips only • This allows them to colonize dead or living organic matter
Nutrition • All fungi are heterotrophic and obtain nutrients from other organisms • The obtain this nutrition by extra-cellular digestion and absorption, not by ingestion
Reproduction • Fungi reproduce by spores, which are single cells surrounded by a wall • Spores are carried by air currents to new sources where they give rise to new hypha • Asexual reproduction: fungi produce spores by mitosis • Sexual reproduction: fungi produce spores by meiosis
Phylum Zygomycota • Example: bread mould (Rhizopus) • Most in this division are terrestrial • Hyphae break into the food source, and are then termed rhizoids • Rhizoids draw water and sugar from the bread (or food source) thus allowing the mould to grow further • After a few days, case-like structure called sporangia appear • Each sporangia can produce several thousand spores
Zygomycota Cont’d • When the sporangia break open, the spores are carried by the air to allow colonization of new areas. • Under less favourable conditions, zygomycotes reproduce sexually • Two hyphae form which conjugate and produce a zygospore • Zygospores stay dormant until growing conditions are correct
Phylum Ascomycota • Examples: mildew, some moulds, some yeasts • Fungi in this division form saclike structures for reproduction • Spores produced by sexual reproduction in these are termed ascospores, and are produced in a sac called an ascus. • Spores produced asexually are called conidia.
Phylum Basidiomycota • Examples: mushrooms, rusts, and puffballs • Under damp conditions, the mycelial mass form knobs which absorb water and grow quite large. • These knobs become spore bearing structures and appear as caps. • The caps have gills that have thousands of reproductive cells called basidia. • Each basidium has several thousand spores.
Phylum Chytridomycota • They are the only fungi with swimming spores. • Most of them are saprophytes which means they obtain nutrients from dead organic matter. • They can be unicellular or multicellular • They can be parasitic and life on decaying plants or insects