Lichens

Definition

Lichens are symbiotic associations between a fungus and a photosynthetic partner, typically algae or cyanobacteria. They form unique structures that can colonize various substrates, often thriving in harsh environments.

5 Must Know Facts For Your Next Test

1. Lichens are indicators of air quality because they are sensitive to pollutants like sulfur dioxide.
2. The fungal component of lichens provides structure and protection, while the photosynthetic partner produces food through photosynthesis.
3. Lichens reproduce via soredia or isidia, which contain both fungal and algal cells.
4. They play a crucial role in soil formation by breaking down rocks into smaller particles.
5. Lichens have been used in traditional medicine and as dyes due to their bioactive compounds.

Review Questions

• What are the two main components of lichens and what roles do they play?
• How do lichens contribute to soil formation?
• Why are lichens considered good indicators of air quality?

Related terms

Mycorrhizae: Symbiotic associations between fungi and plant roots that enhance nutrient absorption.

Hyphae:

The branching filaments that make up the mycelium of a fungus.

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