Lichens

Definition

Lichens are symbiotic associations between a fungus and a photosynthetic partner, usually algae or cyanobacteria. They live in diverse and often extreme environments, playing crucial roles in ecosystems.

5 Must Know Facts For Your Next Test

1. Lichens are composed of two main partners: a mycobiont (fungus) and a photobiont (algae or cyanobacteria).
2. They can survive in harsh conditions, such as arctic tundras, deserts, and high mountain ranges.
3. Lichens contribute to soil formation by breaking down rocks through chemical weathering.
4. They serve as bioindicators for air quality since they are sensitive to pollutants like sulfur dioxide.
5. Lichens reproduce both sexually (via fungal spores) and asexually (through soredia or isidia).

Review Questions

• What are the main components of lichens?
• How do lichens contribute to their ecosystems?
• Why are lichens considered good bioindicators?

Related terms

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

Photosynthesis: The process by which green plants, algae, and some bacteria convert light energy into chemical energy.

Symbiosis: A close ecological relationship between the individuals of two (or more) different species.