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20.1 Kingdom Fungi. What is a Fungus?. The Characteristics of Fungi Fungi are Eukaryotic, heterotrophic, and most are multicellular except yeasts which are unicellular Fungi are everywhere- air, water, basement walls, garden, foods, and between your toes
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What is a Fungus? The Characteristics of Fungi • Fungi are Eukaryotic, heterotrophic, and most are multicellular except yeasts which are unicellular • Fungi are everywhere- air, water, basement walls, garden, foods, and between your toes • Most fungi are decomposers but fungi can spoil food and cause disease too.
The structure of Fungi • Hyphae- threadlike filaments used for absorption of nutrients. • Mycelium- network of hyphae • Different types of hyphae perform different jobs; some anchor, other invade a food source, and some from reproductive structures. • Fungi have cell walls made of chitin which gives the fungi strength and flexibility
Adaptations of Fungi • Fungi use a process called extracellular digestion to obtain nutrients. • Hyphae grow into a food source and release digestive enzymes that break down organic molecules into smaller molecules that hyphae can absorb. • Saprophytes are decomposers and feed on waste or dead organic material • Mutualistslive in symbiotic relationships with other organisms- Lichen • Parasites absorb nutrients from living cells of their hosts • Haustoria- specilaizedhyphae that penetrate and grow into host cells where they can directly absorb nutrients
Reproduction in Fungi • Fragmentation-asexual reproduction which pieces of hyphae break off and grow into a new organism • Budding- asexual reproduction in which new individual pinches off from parent organism • Spores- asexual or sexual; reproductive cells that develop into a new organism.
Adaptive Advantage of Spore • Sporangium- a sac or case in which spores are produced; prevent spores from drying out • Produce a large number at one time, ensuring species survival • Small and lightweight and can be dispersed by wind, water, and animals
20.2 Diversity of Fungi • Mycologist-scientist who study fungi • Fungi are classified according to their method of reproduction • 4Phylums of Fungi • Zygomycotes 2) Ascomycotes 3) Basidiomycotes 4) Deuteromycotes
1. Zygomycotes- 1500 species • Reproduce sexually and asexually by producing spores • Forms stolons- horizontal hyphae that forms mycelium • Form rhizoids- hyphae that penetrate food and anchor the mycelium; secrete enzymes needed for digestion • Asexual Reproduction • Sporangia form on tips of hyphae, splits open and releases spores • Sexual Reproduction (triggered during unfavorable conditions) • Zygospores –thick-walled spores that can withstand unfavorable conditions, remaining dormant until conditions become favorable Example; Rhizopusstolonifer- common bread mold
2.Ascomycotes- Largest Division- 30,000 species • Sac fungi named due to the ascus they form in which sexual spores develop called ascospores • Conidia (chains/clusters of spores) are produced during asexual reproduction by conidophores (hyphae that elongate from the mycelium) • Examples- blue-green, red and brown molds that grow on food; morels and truffles for human consumption and yeasts • Yeasts are unicellular fungi that reproduce via budding; used to produce carbon dioxide and alcohol to make wine, beer and bread
3. Basidiomycotes- 25,000 species • Basidia- club shaped hyphae that produce spores called basidiospores • Have complex reproductive cycles • Examples – puffballs, bracket fungi, rust and smuts
4. Deuteromycotes- 25,000 species • Only reproduce asexually • Examples- penicillin- antibiotic for bacterial infections that grows on fruit; others used to make blue cheese and soy sauce
Mutualism • Mychorrhiza- mutualistic relationship in which a fungus lives with a plant and both benefit. Fungus receive sugars from the plant and the fungi help the plant absorb water and minerals. 80-90% of all plants
Mutualism • Lichens-mutualistic relationships in which a fungus lives with a photosynthetic green algae; need only light, air and minerals to grow; the algae provide food and the fungus absorb moisture and minerals. Pioneers species and can live in harsh environments.