fungi then decaying matter would not be broken down. This means that
carbon would be trapped in the decaying organic matter with nothing to
break it down. This means that energy in our ecosystem would basically
be decreased over time. As a plant or animal died it's organic matter
would be trapped. The nitrogen and carbon inside of it would be trapped.
This would cause our entire ecosystem to collapse and over time if
another organism did not adapt to take the place of fungi, then
eventually all animals including humans would starve to death and die
out. Earth would be completely dead.