Lichens: An Overview
Lichens are unique organisms that arise from a symbiotic relationship between a fungus and an alga or a cyanobacterium. This relationship is so close that lichens are often referred to as a single organism, although they are actually a composite of two or more different organisms.
Structure of Lichens
Lichens have a thallus, which is the main body of the organism. The thallus is made up of fungal filaments intertwined with either algal cells or cyanobacteria. The fungal partner provides a protective structure and absorbs water and nutrients, while the algal or cyanobacterial partner performs photosynthesis to produce food for the lichen.
Ecological Importance of Lichens
Lichens play a crucial role in the environment. They can grow in harsh conditions, such as on rocks, tree bark, and bare soil, making them important pioneers in the process of primary succession. Additionally, lichens are sensitive to air pollution and are used as indicators of air quality. They also provide food and habitat for various organisms.
Study Guide
- Describe the symbiotic relationship between the fungus and the alga or cyanobacterium in lichens.
- Explain the structure of the lichen thallus and the functions of its fungal and algal/cyanobacterial components.
- Discuss the ecological importance of lichens, including their role in primary succession and their use as indicators of air quality.
- Research and present examples of lichens found in different ecosystems and their adaptations to diverse environmental conditions.
- Conduct a field study to observe and document the diversity of lichens in your local area, and analyze the factors influencing their distribution and abundance.
By studying lichens, you will gain valuable insights into the fascinating world of symbiotic relationships, ecological resilience, and environmental indicators.
