green-covered rock with lichen

green-covered rock lichen: natural wonder behold green lichen environment ecosystem moss algae fungi organic photosynthesis oxygen carbon dioxide ecological biodiversity habitat species adaption evolution adaptation symbiosis mutualism parasitism commensalism sustainability conservation preservation biome geology geography climate weathering erosion soil nutrients water hydrology flora fauna invertebrates vertebrates decomposition food chain trophic level energy transfer photosynthetic organisms microorganisms colonization services