|Copyright: Yves Grenier (eev)
|Date Taken: 2008-09-23|
|Camera: Canon 30 D, Sigma 105mm F/2.8 EX 100 Macro|
|Exposure: f/13.0, 1/6 seconds|
|More Photo Info: [view]|
|Photo Version: Original Version|
|Date Submitted: 2008-10-07 7:16|
|[Note Guidelines] Photographer's Note|
|Lichen are usually slow-growing organism of simple structure, composed of fungi and photosynthetic green algae living together in a symbiotic relationship and resulting in a structure that resembles neither constituent. There are about 25,000 species.|
Lichens commonly grow on rocks, trees, fence posts, and similar objects. The body of the lichen is made up of the filaments of the fungus. Its typical greenish gray color is due to the combination of the chlorophyll from the photosynthetic organism with the colorless fungi. Lichens require no food source other than light, air, and minerals. They depend heavily on rainwater for their minerals and are sensitive to rain-borne pollutants. The fungal component of lichens produces acids that disintegrate rock, giving the lichen a better hold and aiding weathering processes, which eventually turn rock into soil. Lichens usually reproduce by the breaking off of a segment that contains both components.
Lichens can withstand great extremes of temperature and are found in arctic, antarctic, and tropical regions.
This specimen was found in abundance on a rocky outcrop along a river in the Temagami region in Northern Ontario.
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