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.