One difference between fungi and most plants noticed by backyard
naturalists is that fungi don't photosynthesize -- they don't contain green chlorophyll so
they don't use sunlight to produce carbohydrate, their food, by combining carbon dioxide
with water. Fungi take their food from their environment in the following ways:
a saprophyte on horse manure
- From dead things, in which case they are known
as saprophytes. In the woods, mushrooms growing on dead,
decaying tree-trunks lying on the ground are saprophytes.
- From other living things, with whom the
fungus lives in a long-lasting or permanent, very close association (symbiosis).
The following symbiotic relationships are possible:
- When the fungus hurts the living thing in or on which it lives, it is
known as a parasite in a parasitic relationship.
If you ever got an ear fungus or athlete's feet, you had a fungal parasite.
- When the living thing on which or in which the fungus
lives is neither hurt nor helped by the fungus, the relationship is referred to as one of commensalism.
Some fungi living harmlessly in the guts of animals are commensals.
When the living thing on which or in
which the fungus lives is helped by the fungus' presence, so that both parties
benefit from the arrangement, the relationship is referred to as mutualism.
One extremely important example of mutualism is that of the fungus-root combination known
While microscopic fungi may absorb dissolved nutrients
from their surroundings directly through their cell walls, nutrients generally enter
larger fungi by soaking into -- or diffusing into -- cobwebby strands of root-like hyphae
growing through the substrate (dead thing or living thing, such as soil or leaf
litter). You can see what hyphae look like here.