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Fungi differ from plants in that they
do not contain chlorophyll and therefore cannot photosynthesize. Instead,
they rely on organic matter for nutrition. Being heterotrophs, fungi
are, in fact, more similar to animals, both evolutionary and physically,
than they are to plants. Fungi can be found “eating” everything
from soil and wood to live plants and live animals. The underground,
vegetative part of fungi called the mycelium extracts nutrients from
the matter. They do this in three ways: as saprophytes,
as parasites, and as mutualistic
organisms (including mycorrhizae). Although
some species of fungi stick to one category, others will switch depending
on their situation.
||Fungi play an extremely important role in decomposing
organic materials to make soil. Included in this phenomenon is fungi's
role in rebuilding the ecosystem of forests after a wildfire. The
fungi (called "after-fire fungi") quickly re-inhabit a
forest after a fire and clean up the remains to make a newly revitalized
environment for other organisms.
Saprophytes live on dead organic matter, including
dead wood, dung, and fallen leaves. Most fungi commonly called
mushrooms are saprophytes, such as the extremely common Agaricus
genus. Perhaps their most important function is the decomposition
of organic matter into soil. Without them, wood, leaves and dung
would take much longer to be broken down into a soil that can
be inhabited by future plants.
Most mushrooms that have a stalk and cap are
saprophytes. Additionally, some molds and other major decomposers
feed on organic waste.
Above: The halucenegenic mushroom Amonita Muscaria,
or as its more commonly know as 'fly aggeric' lives off the
dead oraganic material in the soil
Below : S. Spectabilis shares the nutrients of a fallen
tree with mosses and lichens
Below: While most shelf fungi share mutualistic
bonds with the trees they live on, some can abusively suck the
nutrients from their hosts
Parasitic fungi attack living plants or animals.
They take nutrients from their host and thereby hurt them. Polypores,
or shelf fungi, grow on the sides of trees and feed off of the
live wood. Cyttaria fungi grow on trees and often cause them to
grow galls. Though they live off of trees, the trees are not necessarily
killed. The fungus just continually takes some of what the tree
creates through photosynthesis. When they are killed, though,
the fungus will frequently stay alive as a saprophyte, living
off of the now-dead wood. Parasitic fungi can grow on (and in)
animals as well. Thrush, athlete’s foot and ringworm are
all examples of microfungi that affect humans.
Left: Ringworm is a fungus that
parasitically lives on the surface of human skin; it's common
in tropical climates and is very difficult to rid of
Mutualistic fungi form relationships with organisms
in which both sides benefit (or, at least, are not harmed). It
is important, though, to point out that “mutualistic”
does not mean that each party benefits equally from the ralationship.
Lichens are a common example of a mutualistic relationship between
fungi and algae. As is often grows on rock (Crustose Lichen),
the fungus has no source of nutrients from its surroundings. And
so it receives them from the photosynthesizing algae. In return,
the fungus offers the algae structure and protection. Lace Lichens
(falsely nicknamed Irish Moss) are an example of a lichen that
incorporate yet another partner. It hangs from trees for support.
Perhaps the most important of the mutualistic fungi are mycorrhizae.
Another interesting relationship is with achlorophyllous (non-photosynthesizing)
plants. in this case, fungi extract all the nutrients from the
soil that the plant needs. The fungi, on the other hand, does
not nessecarily benefit.
are a relationships between the roots of plants and fungi in which
the plant receives nutrients that the fungus derives from the
soil and the fungus sometimes receives photosynthesized compounds.
The mycelium of a mycorrhizal fungus sheaths the roots of the
plant, offering several advantages to the plant. Mycelium around
the root ends helps the roots expand farther while protecting
them against other pathogenic fungi and toxins. More importantly
perhaps is that the mycelium extracts nutrients from the soil,
leaving them to be absorbed by the plant. Many plants would not
survive without this mycorrhizal relationship. Eucalycptus trees
are among countless plants that depend on mycorrzae.
Above: Lichen evolved to live in corralation with algea - mycelium,
which is wrapped around algal cells, offers key minerals such
as derived nitrogen to the algea as the the algea contributes
sugar to sustain the fungus
Below: Mushrooms living in a mutualistic relationship with a