Lichen Bioindicators and Symbiosis Sana Bharde
Lichen Symbiosis • Mutualism symbiosis • Mutualism: both organisms benefit • Symbiosis: relationship between species in direct contact • Lichen composes of algae & fungi living in symbiosis • The lichen fungus provides its partner(s) a benefit (protection) and gains nutrients in return through the photosynthetic organism. • a heterotrophic fungi (mycobiont) and a phothosynthetic partner (photobiont) which provides the necessary sugars for the methabolism and releasing oxygen during the process. Photobionts are the primary producers in the lichen symbiosis.
Lichen Algae Fungi Mutualism Lichen Lichens grow in the leftover spots of the natural world that are too harsh or limited for most other organisms. They are pioneers on bare rock, desert sand, cleared soil , dead wood, animal bones, rusty metal, and living bark. Able to shut down metabolically during periods of unfavorable conditions, they can survive extremes of heat, cold, and drought.
Lichens as Bioindicators • Bioindicators are living organisms that reflect environmental health and quality. • Lichens are commonly used as indicators of air pollution, especially sulfur dioxide pollution. • Pollutants in the air dissolved in atmospheric water are damaging to lichens • As a result, there are usually very few lichens around industrial cities and towns. • lichens have been used in different countries as bioindicators of high value forests for conservation and to identify important biodiversity sites • Different lichen species vary in their tolerance to pollution and therefore make very good biological indicators of levels of atmospheric pollution. Lichens depend on atmospheric moisture : rain , fog & dew for growth
CATERGORIES Lichens have a variety of different growth forms foliose(leafy) crustose (crusty) fruticose (shrubby) leprose(powdery)
Lichen Video and Reproduction • http://www.youtube.com/watch?v=g5STBs0n8Bk&feature=related Sing Along: • http://www.youtube.com/watch?v=lWQaEI9fKZc&feature=related • To form a new lichen, fungal spores need to capture new photosynthetic partners after they germinate. Some apparently steal them from other lichens. Others have the good luck to happen upon appropriate partners. In all probability, most just perish alone.
QUESTIONS • Lichens can be divided into groups, based on their appearance, name 4 of these different groups? • What is a practical use for lichens? • How would you describe the appearance of a foliose lichen? • How do Lichens exhibit Mutualism? • What do Lichens need in order to exsist? • What is another name for powdery Lichen?
Answers • Foliose, crustose, fruticose and leprose. • Lichens can be used as bioindicators • Leafy • The lichen fungus provides its partner(algae) a benefit (protection) and gains nutrients in return. • A photosynthetic organism, fungi and a clean atmosphere. • leprose