Transcript Fungi
Fungi All multicellular fungi have hyphae = tubular growth in a substrate (soil, you etc.) Diagram of fungal cell, animal like interior, plant like cell wall. Cell wall of fungi = inner plasma membrane, like animal cells. Outer Chitin (unique) outer sugar Figure 30.1 Fungi in Evolutionary Context Synapomorphies that distinguish the fungi: • Absorptive heterotrophy • Chitin in cell walls Figure 30.3 Yeasts Are Unicellular Fungi Budding: mitosis followed by asymmetrical cell division. Mushrooms, bracket fungi, molds Molds. Reproductive stalks that produce spores Start aquatic, move to land with cuticle, spores, etc. Most of what we see (mushroom, black on mold) is the sporangia for dispersal. Life cycle – sexual, spores for dispersal, “diploid” sort of 30.3 How Do Fungal Life Cycles Differ from One Another? Many species lack a sexual stage—now classified using DNA sequencing. Deuteromycetes or “Imperfect Fungi”—polyphyletic group of species that have not yet been placed in any existing group. 25,000 species Lichens = fungi (base) plus alga (photosynthesis) Some important things about Fungi • absorbtion of water for plants and distribution of nutrients between plants • antibiotics from protective secretions • human diseases: ringworm, valley fever, toe nail rot • agricultural issues; potato blight, wheat rust. Problem of monocultures • world wide loss of frogs. Fungus aids in water uptake Fungus can form home to Bacteria, which can fix nitrogen. Fungi associated with tree root Can share nutrients between plant species – counteract dominance. Tall grass prairie Lots of plants – no dominance Fungi hyphae between plants may share nutrients – offset dominance. Penicillin on agar Ambassador hotel, LA Mushrooms growing in carpet; try soaking your carpet some time – see what grows = spores are everywhere. Fairy rings – fungus growing out from center, culminating in mushrooms = spore producing bodies ringworm Cultured ringworm Potato blight Wheat rust Valley fever • Figure 2. Monthly precipitation and valley fever incidence, 19881998 (top) San Joaquin Valley California, (bottom) southeastern Arizona. [more details] SPOROTRICHOSIS (Sporothrix schenckii Rose-grower’s disease = in soil, starts with thorn prick – gets into lymph system and spreads. Treatible with drugs. Toe nail rot “World wide” decrease in amphibia = frogs, toads? And salamanders? Due to? A) climate change, b) parasites, c) fungi. Climate change = moisture changes, temperature changes. Amphibian problems: mutant frogs ; due to trematode infection Frogs more readily eaten by birds – secondary host of trematode As few as 12 trematode larvae, known as cercariae, can kill or deform a single tadpole by burrowing into their limb regions and disrupting normal leg development, he said. A single infected snail can produce more than 1,000 cercariae in one night. Frogs that become deformed rarely survive long in the wild, he said. Increased trematodes due to increases in nitrogen and phosphorus in water + pollution Fungal infection of frog skin = vacuoles contain sporangia – a water borne primitive fungus =chytridiomycosis Probably spread world wide by dirty boots! Plus frogs more susceptable if climate warmer. Fig. 3. A population pyramid to demonstrate the factors thought to heighten the impact of chytridiomycosis in amphibian populations.