Fungi PPT

Fungi Overview

• Definition: Fungi are essential organisms that play significant roles in terrestrial ecosystems.

Chapter 29 Roadmap

• Major themes in the study of fungi:

  • Fungi as mutualists: Examination of beneficial relationships with other organisms.

  • Fungi as decomposers: Role in nutrient cycling and ecosystem health.

  • Key lineages of fungi: Classification and diversification.

  • Variation in reproductive structures and life cycles.

Structure of Fungi

• Basic Growth Forms:

  • Single-celled forms (Yeasts)

  • Multicellular, filamentous forms (Mycelia)

Importance and Impact of Fungi

Negative Impacts

• Human Diseases:

  • Fungal nail infections

  • Ringworm (circular skin rash)

  • Vaginal candidiasis (yeast infection)

  • Thrush (infects mouth, throat, esophagus)

• Destructive Impacts:

  • Fungi affect food supply negatively.

Positive Impacts

• Source of antibiotics (e.g., penicillin)

• Edible mushrooms are part of numerous cultures

• Yeast is utilized in food production (bread, beer, etc.)

• Enzymes from fungi enhance food products (juice, candy, etc.)

Mycorrhizal Fungi

• Function: Nutrient transfer to land plants.

• Types: Ectomycorrhizal fungi (EMF) vs. Arbuscular mycorrhizal fungi (AMF).

Carbon Cycle and Saprophytic Fungi

• Role of Saprophytes: Digest dead organic matter, facilitating carbon cycling in terrestrial systems.

Methodologies in Studying Fungi

• Scientists have identified approximately 110,000 species of fungi, with hundreds more being discovered each year. It is estimated that up to 6 million species might exist.

• Morphological Analysis: Identifying growth forms and structures like hyphae, mycelium, and reproductive spores.

Reproductive Structures and Life Cycles of Fungi

• Fungi reproduce sexually (via dikaryotic hyphae and meiosis) and asexually (via conidia).

• Types of Reproductive Structures:

  • Swimming gametes (Motile cells in chytrids)

  • Zygosporangia (spore-producing structures)

  • Basidia (club-like cells in basidiomycetes)

  • Asci (sac-like structures in ascomycetes)

Adaptations of Fungi

• Surface Area: Mycelia possess large surface area for nutrient absorption, enhancing efficiency.

• Extracellular Digestion: Fungi digest food externally before absorption, targeting natural compounds like lignin and cellulose.

• Decomposition: Fungi effectively break down tough organic materials through specialized enzymes (e.g., lignin peroxidase).

Key Lineages of Fungi

• Microsporidia: Single-celled parasites characterized by polar tubes.

• Chytrids: Aquatic fungi important for cellulose digestion; some are parasitic.

• Zygomycetes: Soil-dwelling fungi that reproduce sexually and asexually.

• Glomeromycota: Form arbuscular mycorrhizae, beneficial for plant nutrients.

• Basidiomycota: Include mushrooms, vital for wood decomposition.

• Ascomycota: Produce spores in asci; significant for mutualistic relationships and food systems.

Symbiotic Relationships in Fungi

• Fungi engage in various symbioses, ranging from mutualism to parasitism, affecting plant health and ecosystem dynamics.