Does Lichen have a parasitic relationship with fungi and algae

Thanks so much=D

It depends on the researcher, some consider lichens a parasitic symbiosis some consider it a mutual symbiosis. Whether parasitic or mutual it is a symbiosis between a fungus and a photosynthetic partner. The photosymbiont can be either algae or cyanobacteria or both. Tripartite lichens have three partners. The fungal or mycobiont takes up water and mineral nutrients mainly from the atmosphere, through rain and dust. The two photobionts fix carbon and nitrogen. Lichen is like a miniature ecosystem, enabling their colonization of extreme environments that lack soil and nutrients but provide ample sunlight.

No known fungal partner can live on its own. Unlike the photosynthetic partner, that can survive independently. Some consider this to show that the fungus mycobiont partner is exploiting the photosynthetic partner or photobiont. However no photobiont could live *alone* in the locations the lichen symbiosis can occupy, like deserts and polar regions, or on exposed dry surfaces like bare rocks, roofs and tree branches.

Together the mutual symbionts can survive anywhere the tiny sporedia (a cluster of algal cells wrapped in protective fungal filaments) can settle that offers a stable and reasonably well-lit surface. Together they can survive in habitats closed to either, alone.

Lichens are a symbiotic relationship between fungi and algae.

Not parasitic, but symbiosis