end of fungai and beggginign of seed plants

Introduction to Fungi and Their Characteristics

  • Fungi can reproduce both sexually and asexually.

  • Important features of fungi include:

    • Cell walls made of chitin.

    • The ability to photosynthesize (some fungi).

Nutritional Strategies

  • Fungi can obtain nutrients through:

    • Saprobes: Decomposers that get nutrients from dead organic matter.

    • Parasites: Some fungi cause infections in plants and animals.

    • Mutualistic relationships: For example, mycorrhizae that provide nitrogen to plants in exchange for sugars.

Mycorrhizae

  • Mycorrhizae are fungi that form symbiotic relationships with plant roots.

    • They play a crucial role in nutrient absorption, especially nitrogen.

    • An estimated 90% of plant biomass underground is associated with mycorrhizae.

Fungal Structures

  • Basidiocarp: Structure responsible for dispersing spores in fungi like mushrooms.

    • Ascocarp: Structure that produces spores in Ascomycetes fungi.

  • Mycelia: The network of hyphae that make up the body of a fungus.

    • Visible mold appearances are essentially mycelia structures.

Symbiotic Relationships

  • A mutualistic relationship between fungi and algae forms lichens.

    • Lichens are considered a single organism with dual characteristics from both fungi and algae.

Chytrids

  • Chytrids reproduce using motile spores with flagella.

    • Known for causing significant damage to amphibian populations.

Fungal Reproduction

  • Fungi reproduce using structures such as asci (for Ascomycetes), which release spores.

  • Yeast cells resemble coccus morphology and are significantly larger than bacteria.

Distinction Between Fungal Groups

  • Ascomycetes vs. Basidiomycetes: The main differentiator is the structure type and how they reproduce.

  • Dikaryon: A cell with two distinct nuclei, different from a zygote.

Life Cycle of Fungi

  • Fungi undergo a complex life cycle that includes different reproductive stages, involving both sexual and asexual reproduction.

Plant Evolution from Fungi

  • Discussion on the evolution of plants from photosynthetic protists.

    • The evolution leading to seed plants from seedless plants.

    • Comparison of gymnosperms and angiosperms in terms of reproductive strategies, focusing on pollen and seed development.

Gymnosperms vs. Angiosperms

  • Gymnosperms, like conifers, produce naked seeds and often have structures like cones for reproduction.

  • Angiosperms are characterized by their flowering and fruit-bearing structures.

Conclusion and Exam Preparation

  • Students should prepare for the upcoming exam on fungi and plant evolution.

  • Review all main concepts, structures, definitions, and key differences between groups discussed in class.