When you combine fungi with algae and bacteria what do you get? Lichens! Lichens are a unique and dynamic form of life because each species is made up of more than one organism. They are symbiotic in their structure, with each organism species in the lichen relying on the other to survive.
Fungi are the main component of lichens creating its shape and providing the necessary elements for reproduction. Fungi lack chlorophyll resulting in the inability to photosynthesize its own food. As a result, fungi will form a parasitic partnership with algae or cyanobacteria for the creation of food. Algae make up the secondary portion of lichens and depend on fungi for water and mineral absorption.
Lichens date back to approximately 400 million years and are extremely successful in creating a habitat in areas that no other living organism can survive. They can successfully shut down various metabolic processes, remaining dormant, in order to survive harsh or extreme weather conditions. Lichen habitats can include bare rocks, stone walls, dead wood, animal bones and rusty metal. It takes years and possibly even centuries for a lichen to collect and maintain the soil content within its habitat. As long there is an adequate supply of light, clean air and moisture, a lichen can colonize and create its own sustainable living area.
In order to fend off potential predators, including herbivores, plants and microbes, lichens will produce various biochemical compounds aimed to protect both their habitat and their life. These compounds have been cultivated and utilized in dyes, perfumes, foods and medicine.
Caribou, reindeer and mountain goats eat a diet that consists mainly of various lichen species. Black tailed deer are known to eat lichens in the winter when their main food source is inaccessible and buried beneath the snow. Other animals such as birds and squirrels use lichen in their nests. Many small invertebrate species utilize lichens as a form of camouflage for safety and survival.
There are approximately 20, 000 species and 3 forms (Crustose, Foliose and Fruticose) of lichens on record today. Their appearance will vary depending on their internal structure and composition. Some appear leafy with numerous attachments to their habitat while others are more foliar possessing only a singular attachment to their habitat. Crustose lichens are leafy in texture and grown in an outward or radial pattern. Foliose are more paper-like with extremely thin filaments. Foliose lichens tend to experience its growth at the margins and take on a lobe-like appearance. Fruticose lichens are branched and possess great strength when holding onto the surface of its habitat. Growth occurs at the stem of the fruticose lichen.
Lichens are a very common and incredibly fascinating organism that can be found almost anywhere, yet they are considered one of the least known organisms in the world. The next time you step outside have a look around. You will most likely find a thriving colony of lichens close to your feet!
