FUNGI… Is Fungi Fun????? Ridgewood High School

What Are Fungi? Fungi characteristics are…  Eukaryotic  Heterotrophs  Cell wall Cell walls are made of chitin Chitin is a complex carbohydrate that is also found in the external skeletons of insects.

Classification of Fungi Over 100,000 species Classified according to:  Structure and method of reproduction Four main groups are:  Common molds (Zygomycota)  Sac fungi (Ascomycota)  Club fungi (Basidiomycota)  Imperfect fungi (Deuteromycota)

Common Molds Molds that grow on meat, cheese, and bread

Sac Fungi Reproductive structure is the ascus  Ascus contains spores and forms with in the fruiting body. 30,000 species, largest phylum of the fungi kingdom YEAST  Unicellular  Used for baking and brewing

Club Fungi: Mushrooms Club fungi gets its name from a specialized reproductive structure that resembles a club. Basidium: spore- bearing structure  Found on the gills that grow on the underside of mushroom caps

Fungal Anatomy Hyphae and mycelium Chitin or cellulose cell walls Asexual and sexual reproduction Above-ground sexual structure

Structure of Fungi All fungi are multi-cellular except yeast Multi-cellular fungi composed of tiny filaments called hyphae  Hypha is one cell wall thick and in some fungi cross walls can allow cytoplasm and nuclei to travel between cells.  Fungi with out hyphae lack cross walls also contain nuclei.

The Filamentous Body of a Fungus (a (a) Mycelium (b) (b) Individual Hyphae (c) Hyphal Cells (cutaway) Cell Walls Septum Pore Cytoplasm Haploid Nuclei

Structure of Fungi

Chytrid FilamentsMale Female Process of Sexual Reproduction: the orange structures visible release male gametes; the clear structure release female gametes. Chytrid gametes have flagella which aid in the dispersal of the zygotes because the phylum is mainly aquatic.

Structure of Fungi The bodies of multi-cellular fungi are composed of many hyphae tangled together into a thick mass called a mycelium.  Mycelium is well suited to absorb food because it permits a large surface area to come in contact with the food source through which it grows.

Structure of Fungi Fruiting body: is a reproductive structure that develops from the mycelium that grows below the surface of the ground.  Clusters of mushrooms are often part of the same mycelium, which means they are from a single organism

Ecology of Fungi Fungi are heterotrophs  They cannot make their own food  They cannot move to obtain their food  The mycelium grows rapidly into the tissue and cells of plants and trees.

Ecology of Fungi Saprobes: organisms that obtain food from decaying organic matter. Parasites: harmful to other organisms live directly on or in other organisms Symbiont: live in close and mutually beneficial association with other species

Fungus as Decomposers Recycle nutrients by breaking down the bodies and wastes of other organisms Release digestive enzymes that break down leaves, fruit and other organic materials.

Fungus as Parasites Parasitic fungi cause serious plant and animal diseases and some in humans.  Plant Diseases: corn smut (destroys the corn kernals), mildews (infect fruits)  Loose 50% of crops in certain tropical regions to fungus.  Human Disease: athletes foot (the mycelium grows in the outer layer of skin and spreads), ring worm, and yeast infections (candida albicans)  Animal Disease: Cordyceps infects grasshoppers in rain forest

Cordyceps of a Grasshopper

Human Parasitic Fungus Athletes Foot

Symbiotic Fungal Relationships Mutualism  Some fungi form symbiotic relationships in which both partners benefit. Two mutualistic associations are lichens and mycorrbizae which are essential to ecosystems.

Lichens Lichens are not single organisms They are symbiotic associations between a fungus and a photosynthetic organism  The fungus is lichens is called ascomycetes  The photosynthetic organism is green alga or cynobacterium Location: resistant to drought and cold  Live almost everywhere rocks in deserts  Often the first organism to inhabit a barren environment…Primary Succession

Mutualistic Relationship Mycorrhizae: association of plant roots and fungi More then 80% of plants have this relationship with fungus Benefits: hyphae of fungi aid plants in absorbing water and minerals; plants in return provide the fungi with the products of photosynthesis.