Presentation on theme: "Domain Eukarya Kingdom Fungi. Anatomy of a fungus Most fungi grow as multicellular mycelia made up of long, thin filaments called hyphae. Most of a fungi."— Presentation transcript:
Domain Eukarya Kingdom Fungi
Anatomy of a fungus Most fungi grow as multicellular mycelia made up of long, thin filaments called hyphae. Most of a fungi will be invisible to us. Only the reproductive structures above ground will be seen.
Anatomy of a fungus The hyphae of fungi may or may not be divided into separate cells by septa SeptaNo septa
Fungi can be multicellular or unicellular Multicellular mycelia:. This mycelium is from the rind of a piece of Melbury cheese. The yeast pictured here is baker’s yeast, Saccharomyces cerevisiae.
Hyphae Reproductive structure Mycelium Septa Cell wall Pore Fungi are absorptively heterotrophic Fungi can break down almost any type of organic substance –secrete enzymes to digest food outside –absorb nutrients back in –may be saprobes, detritivores, parasitic, mutualistic, predatory Fungal morphology is associated with their mode of nutrition: the fungal mycelium maximizes surface area in relation to volume.
Fungal decomposition (saprophytic)
Parasitism Although many fungi infect humans, relatively little human disease is due to fungi. Parasitic fungi cause major damage to crops such as wheat, corn, and barley.
Fungi reproduce by producing spores The reproductive structures of fungi produce haploid spores spore A new fungal mycelium begins with the germination of a haploid spore
The Fungal Life Cycle ‘vegetative’ life form typically haploid May reproduce asexually through haploid spores
The Fungal Life Cycle Sexual reproduction through –cytoplasm fusion --> dikaryotic stage (n + n) or heterokaryotic –nuclear fusion--> diploid stage –typically rapid meiosis--> haploid spores
Four groups of Fungi
Chytridiomycota Mainly aquatic Flagellated spores Basal group of the Fungi
Phylum Zygomycota Rhizopus (bread mold), fruit rot when two different hyphae join together for sexual reproduction, they form a swollen, thick-walled structure (zygosporangia) that links the hyphae together
Figure 31.7 The life cycle of the zygomycete Rhizopus (black bread mold)
Figure 31.7x2 Mature zygosporangium
Bread mold Bread Molds, Black Bread Mold, Rhizopus stolonifera, not only grow on Bread, but anywhere there are water and nutrients.
Phylum Ascomycota Sac Fungi Fruiting structure called an ascocarp Produce spores in sac-like compartments called asci Morel Truffle
Figure The life cycle of an ascomycete Asexual spores produced in conidia Sexual spores produced in ascocarps
Phylum Basidiomycota Club Fungi: Mushrooms, shelf fungi, rusts and smuts, puffballs Seldom reproduce asexually.
Club fungi reproduce sexually by forming spores in a structure called a BASIDIUM (BASIDIA) which can be found lining gills inside the BASIDIOCARP (the mushroom cap).
Mushrooms Poisonous Edible Hallucinogenic
Table 31.1 Review of Fungal Phyla
“Phylum” Glomeromycota? Mycorrhizae are fungi that associate with plant roots and receive sugars from them. Two types: –Exomycorrhizae –Endomycorrhizae (also called arbuscular)
Root cells EMF Common in colder northern climates (decomposition is slow) The fungus breaks down organic material and delivers nitrogen to the plant. Ectomycorrhizae grow on the surface of plant roots without penetrating the cells.
AMF Root cells Root hair Common in warmer grasslands & forests (decomposition is rapid). The fungus delivers phosphorus to the plant. Arbuscular mycorrhizae penetrate the cells of the plant root.
Number of AMF species Shoot biomass Plant species diversity Effect of AMF species diversity on plants: Mutualisms: Increasing the diversity of mycorrhizae in a given habitat increases plant species richness and productivity.
Mutualisms Lichens –Lichens are associations of a fungus with either an alga or cyanobacterium. Lichens are the dominant species in tundra habitats and are important in breaking down rock to form soil.
Asexual reproduction occurs when “mini-lichens” are produced. Asci produced by fungus Fungal layer Algal layer Substrate Figure 29.11a
Types of Lichens crustose, fruticose, foliose
Dutch Elm Disease Entered the U.S. in the 1930’s Has been moving westward ever since Chicago lost 119,000 trees in 3 years
Entered the U.S. early 20th century Before: as many as 1 in 4 trees were chestnuts (e. of Mississippi) 100,000s of trees lost (3.5 billion in 40 years?) Tree now present as an understory tree produced by sprouting from roots Chestnut blight
Cell walls of fungi are made of chitin (Cell walls of plants are made of cellulose) Chitin also makes up the exoskeleton of arthropods
Fungi used to be classified with plants Plants Photosynthetic Cell wall made of cellulose Develop from embryos Fungi Heterotrophic Cell wall made of chitin Develop from spores …but there are major differences