ch 30 fungai

Overview of Fungi and Protests

• Focus on understanding major groups of protests before quiz.

• Distinction between identifying groups and matching facts.

Groups of Protests

• Opportunistic Quiz Structure: Facts or groups can lead to questions.

• Key Example: Fungi and their relation to animals in the phylogenetic tree (epistocons and amorphia).

Identifying Groups

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• Two Approaches: Knowing facts about groups or identifying groups based on their characteristics.

• Example Question: "Which group is characterized by the presence of pseudopodia?" Answer is Amoebozoa.

Characteristics of Major Groups

• Excavata: Characterized by greatly reduced mitochondria.

• Stromatophytes: Notable for having two differently structured flagella.

  • Includes diatoms and water molds.

• Phytoplankton vs. Seaweed: Seaweed refers to any aquatic, photosynthetic plant-like structure, though not necessarily a plant.

Fungal Characteristics

• Fungi are often described by their observable traits.

• Chitin Cell Wall: All fungi have a cell wall composed of chitin, different from plant cell walls.

• Hyphae and Mycelium:

  • Hyphae: Elongated cells that can branch and form mycelium.

  • Mycelium is what we see as fuzzy or hairy colonies in the environment.

Fungi's Role in Ecosystems

• Decomposers: Essential in breaking down organic material, including wood.

• Nutrient Recycling: Without fungi, the decomposition process would take significantly longer, leading to buildup of dead material.

• Fungi contribute to soil health and nutrient availability for plants.

Types of Fungi

• Single Celled: Yeasts are the most common fungi, typically round in shape.

• Multicellular Fungi: Manifest as mushrooms, which are reproductive structures that release spores.

  • The majority of fungal mass is mycelium, often underground.

Unique Characteristics of Fungi

• Fungi can reproduce both asexually and sexually, complicating their life cycles.

• Different types of heterotrophic nutrition:

  • Saprobes: Decomposing dead organic material.

  • Parasitic: Living off living hosts, causing disease or harm.

Hyphae Structure

• Septa: Cross-walls that may separate hyphae.

• Coenocytic Cells: Hyphae can lack septa and share cytoplasm, allowing for nutrient sharing across long distances.

Largest Known Fungus

• Armillaria ostoyae: The humongous fungus, covering approximately 2,400 acres, showcasing the extensive underground network of mycelium.

  • Capable of transferring nutrients across large distances through its interconnected structure.

Comparison of Fungi and Other Organisms

• Fungi digest food externally via enzymes, then absorb the nutrients, contrasting with animals that ingest food internally.

• Ecological Impact: Fungi’s role in nutrient cycling highlights their importance within ecosystems.

Key Concepts to Remember

• All fungi have a chitinous cell wall.

• Hyphae and mycelium are fundamental structures in fungi.

• Fungi can live as saprobes or parasites and have significant ecological and biological roles.