kingdom fungi. dna evidence now indicates kingdom fungi is more closely related to animals than...
TRANSCRIPT
KINGDOM FUNGIKINGDOM FUNGI
DNA evidence now indicates kingdom fungi is more closely
related to animals than plants!!!!
The Body of a Fungus• Fungi exist mainly in the
form of slender filaments (hyphae).– long chains of cells
joined end-to-end divided by cross-walls• rarely form complete
barrier• cytoplasm freely
streams in hyphae– mycelium - mass of
connected hyphae
General Characteristics–Fungi are heterotrophs.
(Decomposers)–Fungi have cell walls that include
chitin and not cellulose like plants do.
–Chitin is also found in insects!!!
How Fungi Reproduce• Spores most common means
of reproduction– may form from asexual
(mitosis) or sexual processes (meiosis)
– most often dispersed by wind but some spread by insects or other small animals
– Fungi are grouped by the way they reproduce
How Fungi Obtain Nutrients• All fungi obtain food by
secreting digestive enzymes and then absorbing the organic molecules produced (external digestion).– extensive hyphae
network provides enormous surface area for absorption
– many fungi able to break down cellulose in wood
Ecology of Fungi
• Fungi and bacteria are the principal decomposers in the biosphere.– mineral cycling
• Fungi are virtually the only organisms capable of breaking down lignin.
• Fungi often act as disease-causing organisms for both plants and animals.– agricultural damage– human health
Kingdom Fungi – you must know 4 Major Phyla
1. Phylum Zygomycota = the Bread Molds
Rhizopus – black bread mold
2. Phylum Ascomycota = the Sac Fungi
Yeast, morels, truffles
3. Phylum Basidiomycota = the Club Fungi
Mushrooms, puffballs, bracket fungi, rusts, smuts, toadstools
4. Phylum Deuteromycota = the Fungi Imperfecti
-Regarded as imperfect because they exhibit no sexual stage has been observed in their life cycle
-Members are not closely related and are not necessarily similar in structure or appearance; do not share a common ancestry, polyphyletic = coming from many ancestors – hmm weird
Deuteromycota (Imperfect Fungi)
Deuteromycota – the Fungi Imperfecti
• Resemble Ascomycetes, but their reproductive cycle has never been observed
• Penicillium used to be imperfect but is not anymore!!!
• Different from Ascomycetes because there is a definite lack of sexual reproduction, which is why they are called Imperfect Fungi
Penicillium fungi
Up Close
-are primarily decomposers
-asexual spores may be produced in sporangia
-sexual reproduction occurs between + and – strains forming a 2n zygote; a zygospore develops and may lie dormant for a long period of time; meiosis occurs just before germination
-only the zygote is diploid; all hyphae and asexual spores are haploid
Zygomycota (Rhizopus) the Common Molds
Zygomycota – common molds
The fungal mass of hyphae, known as the MYCELIUM penetrates the bread and produces the fruiting bodies on top of the stalks
Mycelia = a mass of hyphae or filaments
Rhizoids = root-like hyphae
The zhizoids meet underground and mating occurs between hyphae of different molds (SEXUAL REPRODUCTION)
Ascomycota
• Very large group including yeasts, common molds, and morels
• Named for reproductive structure ascus
Ascomycota
• Yeasts– unicellular - most reproduction is asexual and
takes place by cell fission or budding• ferment carbohydrates• play a leading role in genetic research
Basidiomycota
• Most familiar fungi (mushrooms, toadstools, puffballs, rusts, and smuts)– named for characteristic sexual reproductive
structure, basidium
Basidiomycete or Club Fungi
Basidiomycota
Bracket Fungi
Puff Balls
Mushrooms
Jelly Fungi
Basidiomycete Fungi that all produce Basiospores
Other Basidiomycetes Rusts and Smuts
Rust infecting wheat leaves
Rust infecting a Leaf
Whitrot Smut digesting old wood
Lichens• Lichens are symbiotic associations between a
fungus and a photosynthetic partner.– usually ascomycetes
• Specialized fungal hyphae penetrate photosynthetic cells and transfer nutrients to fungal partner.
– Durable fungus, combined with photosynthetic properties, has enabled lichens to invade harsh climates.
– extremely sensitive to pollutants
Crustose
Foliose
Fruticose
Mycorrhizae
• “myco” = fungus and “rhiza” = root• Symbiotic association between plant
roots and fungi• Several different types of association
(defined by structure of fungus:plant interface)
Mycorrhizae
The plant photosynthesizes while the fungus more efficiently takes up nutrients and water from the rhizosphere than the roots would alone.
Plant benefits include:•Improved nutrient/water uptake •Improved root growth •Improved plant growth and yield •Improved disease resistance •Reduced transplant shock •Reduced drought stress