Two common examples of mutualism in the tundra biome include the beneficial coexistence between the alga and the fungus in a lichen and the reciprocal partnership between tundra swans and sago pondweed. Mutualism is a type of symbiotic relationship wherein two or several different species derive shared benefits by living in close proximity with one another.
A biome is a geographical and ecological division of the Earth, which is characterized by a unique flora and fauna that thrive under certain climatic and environmental conditions. The tundra biome is defined as a region comprising a low variety of plants and animals, limited food sources, minimal precipitation, brief growing period and exceedingly cold temperatures.
Due to competition and the scant availability of nutrients, organisms form relationships with other organisms to ensure continued survival. One of the most abundant organisms in the tundra biome are lichens. A lichen consists of a fungal component called a "mycobiont," which forms a mutualistic relationship with the algal component known as a "photobiont." The fungus protects the alga from becoming dehydrated by constantly supplying it with water, while the alga synthesizes food for the fungus. Another mutually beneficial partnership in the tundra is between tundra swans and sago pondweed, where the swans utilize the pondweed as a source of sustenance during the birds' seasonal movement, in exchange for seed dispersal.