This demonstration will show the function of decomposers using yeast, on of the members of the Kingdom Fungi.
This is a very simple demonstration. You just cut two slices off of a peeled banana, that are relatively the same size. Place each slice in a separate baggie. Sprinkle some Baker's yeast over one of the slices in the bag and then seal it up.
The other one you just seal up. It is your control. Place them somewhere they won't be disturbed and check them every day for a week or more.
Here they are, one week later. I meant to get daily photos to show the progress, but with the holiday season and our going out of town, I couldn't. The control banana has browned a little, but has not really decomposed at all. The banana with the yeast has, however, become one substance as the yeast has broken down the banana. You can't really see where the banana ends and the yeast ends.