I.  If someone mentions fungus the first thing that pops into your 
        head is probably a mushroom, but it is just one part of a 
        complicated life cycle of one organism in this kingdom 
        called fungi. Other organisms in this kingdom can cause 
        diseases of both humans or plants while still other can 
        cure disease like Penicillium. Some are economically 
        important like yeast that help us in baking and brewing, 
        while others are just a pain like mold and mildew in the bathroom. 
        
        A.  Basically the "place in the food chain" for all fungi is 
            decomposer; even though some are saprophytes and 
            others parasites. All absorb nutrients like bacteria, by 
            secreting enzymes outside their bodies and digesting 
            complex molecules which can be absorbed through cell 
            walls. 
        B.  Cell walls of these organisms are generally composed 
            of chitin, just like arthropods which is a link towards animals 
            and definitely not plants. The inability to move about is 
            another nonplant characteristic.
        C.  The most visible part of most fungi, like a mushroom, is 
                a reproductive structure, but the main body or mycelium 
                of most fungi is an interwoven mass of threadlike filaments 
                one-cell thick called hyphae. It depends on the species as 
                to whether the hyphae are subdivided by partitions called 
                septa or not, each containing many or one nuclei. 
                Reproduction includes an alternation of generations 
                using mitosis and meiosis and some spores are 
                produces asexually while others are produced sexually, 
                but all are haploid.

II.  Characteristics of Fungi:

 

1. Fungi are eukaryotic

2. The majority are multicellular ( yeast is single celled)

3. Lack chlorophyll

4. Nutritionally they are heterotrophic, they digest food outside the 
        body and absorb it . They are saprophytes, parasites and some 
        are mutualistic.

5. Their basic body plan constitutes a mass of netlike filaments 
        called hyphae. The entire mass is called the mycelium. 
        Most fungal hyphae are divided into cells by cross walls 
        called septa. Some fungi are aseptate, lacking cross walls. 
        They are said to be coenocytic. Some types of fungi contain 
        lateral hyphae that absorb nutrients from other organisms, 
        called haustoria.

6. Reproduction is accomplished by the release of sexual or 
        asexual spores. For many species of fungi sexual reproduction 
        is a contingency used when environmental conditions are difficult. 
        Under favorable conditions asexual spores are produced by the 
        millions and dispersed over a large area.  Haploid conditions prevail 
        in the life cycles of most fungi. Conjugation occurs in many fungal
        species.

 

DIVISION (PHYLA)	EXAMPLE ORGANISMS	CHARACTERISTICS
Chytridiomycota	Chytrids	Probable link between fungi and protist, only example with flagellated spores
Zygomcota	Rhizopus - black bread mold	Asexually -> spores resistant to freezing & drying
Ascomycota	Saccharomycetes - yeasts Aspergillus - some toxic, some carcinogenic, some used in dairy industry; Dutch Elm disease truffles	Asexually -> naked spores
Basidiomycota	Neurospora - bread mold eatable mushrooms poisonous mushrooms shelf & bracket fungi puffballs plant pathogens	Sexually -> spores
Deuteromycota	Penicillium - antibiotic ringworm & Athlete’s foot - (human parasites) black spot & tomato blight- (plant pathogens)	Asexually -> spores
Mycophycophyta	lichens - algae + fungi	mutual exploitation , able to live where neither can survive alone

 

III.  Diversity of Fungi:

 

Fungi are classified into units called Divisions. There are 4 divisions based primarily on variations of sexual reproduction. The names of the divisions are based on the sexual structure that characterizes that group of fungi.

 

1. Division Zygomycota: These are mostly terrestrial fungi that live in soil or on decaying plant or animal material. Their hyphae are coenocytic, with many haploid nuclei. Asexual spores, usually wind swept, are produced by structures called sporangia, at the tips of aerial hyphae. Sexual reproduction involves the formation of resistant bodies called zygosporangia that can remain dormant when the environment is too harsh for growth. Examples are black bread mold ( Rhizopus stolonifer).

 

 

 

Division Ascomycota: These are sac fungi. They range from unicellular yeast to large cup fungi. The sexual reproductive structure is the asci, a small sac like structure. These asci are packed into large fruiting structures called ascocarps. The hyphae are multicellular septate structures. They lack sporangia but reproduce asexually by producing chains of spores at the tip of specialized hyphae. These spores are called conidia. Two types of spores are produced by this type of fungus, conidia and ascospores. Conidia are asexual, while the ascospores are sexual.

 

Reproduction of Ascomycetes:

 

 

 

These fungi are important in decomposing lignin and collagen of dead plants and animals. Some are mutualistic ( lichen) and many are parasitic to plants ( powdery mildew and Dutch elm disease).

 

Division Basidomycota: The mushroom, shelf fungi, puffballs and stink horns are examples of this division. The name is derived from the sexual reproductive structure called the basidium. The club like shape gives the name to some of the most common fungal types in this division.

 

Division Deuteromycota: These organism have no known sexual life style. They are also known as fungi imperfecti. Examples of this group are Penicillium and Arthrobotrys.

 

 

Lichens: Highly integrated symbiotic associations of millions of algal cells tangled in a lattice of fungal hyphae. Classification: leafy ( foliose), fruticose ( shrubby), and crustose ( crusty).

 

Mycorrhizae: mutualistic association of a fungus and a root. 90% of the fungi is bascidomycota