- Myco- = fungus
- -ology= study of
General Characteristics of Fungi:
- Decomposers – the best recyclers around
- No chlorophyll – non-photosynthetic
- Most multicellular (hyphae) – some unicellular (yeast)
- Cell walls made of chitin (kite-in) instead of cellulose like that of a plant
- Are more related to animals than the plant kingdom
- Lack true roots, leaves, and stems
- Absorptive heterotrophs
- Digest food externally and then absorb it
- Lack of chlorophyll affects the lifestyle of fungi…
- Not dependent on light
- Can occupy dark habitats
- Can grow in any direction
- Can invade the interior of a substrate with absorptive filaments
- Body of fungus made of tiny filaments or tubes called hyphae .
- Contain cytoplasm and nuclei (more than 1)
- Each hyphae is one continuous cell
- Cell wall made of chitin
- A tangled mess of hyphae is called mycelium
- Rhizoids are root-like parts of fungi that anchor them to the substrate (whatever they are bonding to)
- Mycelium increases the surface area of the fungi to absorb more nutrients.
CLASSIFICATION OF FUNGI:
- Fungi can be classified into 5 groups
- Fungi evolved from an aquatic, flagellated ancestor
- Glomeromycetes (Mycorrhizae fungi); Mycorrhizae are mutually beneficial associations of plant roots and fungi
o Common and may have enabled plants to colonize land
o Help create an extending network for the plant to absorb more nutrients and water
- Ascomycetes (Sac fungi)
o Truffles and yeast
- Basidiomycetes (Club fungi)
o Puff ball mushroom
- Zygomycetes (Zygote fungi)
- Fungi produce spores in both asexual and sexual life cycles
- Mushrooms let out spores from their pores that are carried by the wind to meet other spores and become new fungi
- Yeast are unicellular and divide into new fungal cells (mitosis)
o In some fungi, fusion of haploid hypha produces a heterokaryotic stage containing nuclei from two parents (fusion of cytoplasm)
o After the nuclei fuse, meiosis produces haploid spores (can grow in fungi and are the asexual part of the life cycle)
General Fungi Reproduction Cycles:
- But fungal groups do differ in their life cycles and reproductive structures
Reproduction in Basidiomycetes:
- Basidiomycota (typical mushroom)
- FUNGI NUTRITION:
- Fungi absorb food after digesting it outside their bodies
o Fungi are heterotrophic eukaryotes
- Fungi use digestive enzymes to break down their food then absorb the liquid. (acquire nutrients such as nitrogen)
- trap nematodes (little worms who feed on fungi) and paralyze them with special juices then absorbs and digests the nitrogen out of them.
3 Modes of Nutrition in Fungi:
- Mutualists (symbionts)
- Use non-living organic material
- Important scavengers in ecosystems
- Important in recycling carbon, nitrogen, and essential mineral nutrients
- Use organic material from living organisms, harming them in some way
- Range of hosts from single-celled diatoms to fungi, to plants to animals to humans
- Mutualists (symbionts)
- Fungi that have a mutually beneficial relationship with other living organisms
- Mycorrhizae – beneficial relationship with fungi with plant root
o More than 90% of plants in nature have a mycorrhizal in roots (example: Truffles- expensive delicacy!)
- Lichens – associations of fungi with algae or cyanobacteria
o Food source for animals, breaking down rocks into soil
- Parasitic fungi harm plants and animals
o Parasitic fungi cause 80% of plant diseases
o Can kill plants and affect crops
- Many fungi are harmful to humans
- Can cause human diseases – allergies, athletes foot, ringworm, yeast infection
- A contagious fungal infection having a characteristic red ring that can appear on an infected person’s skin
- Can affect the scalp, the body (particularly the groin), the feet, and the nails
- Also called Tinea
BENEFITS OF FUNGI
- Fungi also form mutualistic relationships with animals
- Some animals benefit from the digestive abilities of lichens
- Lichens consist of fungi living mutually with photosynthetic organisms
o Lichens consist of algae or cyanobacteria (protists or bacteria) within a fungal network
- Fungi have enormous ecological, economic and practical uses
o Ecological= fungi are essential decomposers; mycorrhizae increase plant growth
o Economic/Practical= antibiotics and food (making bleu cheese/ truffles and truffle hunting)
- More Useful Fungi:
- Yeasts – baking and brewing beer
- Antibiotics – penicillin & cephalosporin
- Production of organic acids – citric acid in Coke
- Steroids and medicines – birth control pills
MAJOR PARTS OF A MUSHROOM:
- Cap (Pileus) – The top part of the mushroom.
- Cup (Volva) – A cup-shaped structure at the base of the mushroom. The basal cup is the remnant of the button (the rounded, undeveloped mushroom before the fruiting body appears). Not all mushrooms have a cup.
- Gills (Lamellae) – A series of radially arranged (from the center) flat surfaces located on the underside of the cap. Spores are made in the gills.
- Mycelial threads – Root-like filaments that anchor the mushroom in the soil.
- Ring (Annulus) – A skirt-like ring of tissue circling the stem of mature mushrooms. Not all mushrooms have a ring.
- Scales – Rough patches of tissue on the surface of the cap
- Stem (Stape) – The main support of the mushroom; it is topped by the cap. Not all mushrooms have a stem.
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