Lichens and mycorrhizae are examples of mutualists. Lichens can absorb mineral ions, extract nitrogen from the air, and colonize new habitats. C. Mycorrhizae form when fungi enter into mutualistic interactions with tree roots, which benefit greatly from the fungus's ability to absorb needed nutrients. D. Collectors have seen a decline in populations of wild mushrooms since the early 1900s, most probably due to the increased levels of pollutants in the air. I. Characteristics of Fungi A. Mode of Nutrition 1.
Fungi are heterotrophs that utilize organic matter.
Saprobes get their nutrients from nonliving matter. Parasites thrive on tissues in living hosts. All fungi rely on extracellular enzymatic digestion and absorption. Fungi are valuable decomposers in the environment. B. Major Groups 1.