Fungi ppt

Fungi : 

Fungi Chapter 21

The Kingdom Fungi : 

Section 1 The Kingdom Fungi

What are Fungi? : 

What are Fungi? Fungi are eukaryotic heterotrophs that have cell walls The cell wall is made of chitin, the same material that makes up the external skeletons of insects Fungi digest their food outside of their bodies and then absorb it Many feed by absorbing nutrients from decaying matter Others live as parasites

Structure and Function of Fungi : 

Structure and Function of Fungi Yeasts – unicellular All other fungi – multicellular Composed of thin filaments called hyphae Some hyphae have cross walls, others do not

Fungus Structure : 

Fungus Structure Mycelium – many hyphae tangled together into a thick mass Fruiting Body – reproductive structure

Reproduction in Fungi : 

Reproduction in Fungi Most fungi reproduce sexually and asexually

Reproduction in Fungi : 

Reproduction in Fungi Hyphae break off and begin to grow on their own Some fungi produce spores, which scatter and grow Sporangia – structures that produce spores Sexual reproduction involves two mating types: “+” (plus) and “–” (minus) Hyphae of opposite mating types meet and fuse, bringing “+” and “–” nuclei together in one cell Asexual Reproduction Sexual Reproduction

How Fungi Spread : 

How Fungi Spread Many fungi produce dry spores that scatter easily in the wind If these spores are to germinate, they must land in an environment with the proper combination of temperature, moisture, and food so they can grow Other fungi are specialized to lure animals, which disperse spores over long distances

Classification of Fungi : 

Chapter 21 Classification of Fungi

Classification of Fungi : 

Classification of Fungi Fungi are classified according to their structure and method of reproduction. The four main groups of fungi are: Common molds (Zygomycota) Sac fungi (Ascomycota) Club fungi (Basidiomycota) Imperfect fungi (Deuteromycota)

Common Molds : 

Common Molds Zygomycetes – familiar molds that grow on meat, cheese, and bread Have life cycles that include a zygospore (contains zygotes formed during the sexual phase of the mold’s life cycle)

Structure and Function of Bread Mold : 

Structure and Function of Bread Mold Black bread mold (a zygomycete) has two types of hyphae Rhizoids - rootlike hyphae that penetrate the bread's surface Stolons - stemlike hyphae that run along the surface of the bread Reproduce both sexually and asexually

Life Cycle of Black Bread Mold : 

Life Cycle of Black Bread Mold

The Sac Fungi : 

The Sac Fungi Members of the phylum Ascomycota More than 30,000 species Named for the ascus – a reproductive structure that contains spores Life cycle includes both sexual and asexual reproduction

Life Cycle of Sac Fungi : 

Life Cycle of Sac Fungi Sexual Reproduction

Yeasts : 

Yeasts Unicellular fungi Yeasts reproduce sexually and asexually Budding – the process of asexual reproduction in yeasts Dry granules of yeast contain ascospores, which become active in a moist environment

The Club Fungi : 

The Club Fungi The phylum Basidiomycota, or club fungi, gets its name from a specialized reproductive structure that resembles a club The spore bearing structure is called the basidium Found in the gills on the underside of mushroom caps Has a complicated life cycle

Life Cycle of Club Fungi : 

Life Cycle of Club Fungi

The Diversity of Club Fungi : 

The Diversity of Club Fungi

The Imperfect Fungi : 

The Imperfect Fungi Phylum Deuteromycota Cannot be placed in other phyla because researchers have never been able to observe a sexual phase in their life cycles The species Penicillium notatum is a mold that frequently grows on fruit Source of the antibiotic penicillin

Ecology of Fungi : 

Section 3 Ecology of Fungi

All Fungi are Heterotrophs : 

All Fungi are Heterotrophs Rely on other organisms for their energy Many are saprobes – organisms that obtain food from decaying matter Some are parasites – harm other organisms while living on or in them Some are symbionts – live in mutually beneficial association with other species

Fungi as Decomposers : 

Fungi as Decomposers Fungi play an essential role in maintaining equilibrium in nearly every ecosystem Fungi recycle nutrients by breaking down the bodies and wastes of other organisms

Fungi as Parasites : 

Fungi as Parasites Can cause serious plant and animal diseases A few cause human diseases

Plant Diseases : 

Plant Diseases Responsible for the loss of about 15% of crops grown in temperate regions Responsible for up to 50% of crop loss in tropical areas

Human Diseases : 

Human Diseases Examples of fungus-caused disorders include: Athlete’s foot Ringworm Thrush

Other Animal Diseases : 

Other Animal Diseases Deadly grasshopper infection by one fungus called Cordyceps

Symbiotic Relationships : 

Symbiotic Relationships Some fungi form symbiotic relationships in which both partners benefit Examples: Lichens Mycorrhizae

Lichens : 

Lichens Symbiotic association between a fungus and a photosynthetic organism (either green algae or cyanobacteria) The algae or cyanobacteria carry out photosynthesis, providing the fungus with a source of energy The fungus provides the algae or bacteria with water and minerals and protects the green cells from intense sunlight

Structure of Lichens : 

Structure of Lichens

Lichens : 

Lichens

Mycorrhizae : 

Mycorrhizae Association of plant roots and fungi Researchers estimate that 80% of all plant species form mycorrhizae with fungi