Lichen

Definition

Lichens are symbiotic associations between a fungus and a photosynthetic partner, usually algae or cyanobacteria. They play crucial roles in ecosystems as bioindicators and pioneers in soil formation.

5 Must Know Facts For Your Next Test

1. Lichens consist of a mutualistic relationship primarily between fungi (mycobiont) and algae or cyanobacteria (photobiont).
2. They can survive in extreme environments, including arctic tundras, deserts, and high-altitude regions.
3. Lichens reproduce both sexually through fungal spores and asexually via soredia or isidia.
4. They are important ecological indicators for air quality as they are sensitive to pollutants like sulfur dioxide.
5. Lichens contribute to soil formation by breaking down rocks through physical and chemical means.

Review Questions

• What are the two main components that make up lichens?
• How do lichens reproduce?
• Why are lichens considered important bioindicators?

Related terms

Mycobiont: The fungal component of a lichen.

Photobiont: The photosynthetic partner in a lichen, usually an alga or cyanobacterium.

Soredia: Asexual reproductive structures in lichens consisting of fungal hyphae wrapped around algal cells.