Subject: What food do the organisms need on the rotting log?

Our teacher wanted us to do a report on rotting log.
 While walking in the forested area one day with 5 of her pupils, Mdm Tan 
found a rotting log on the ground. She discovered that there were some 
organisms 
growing, crawling on it's surface or hidden in it. She brought the rotting log 
back to the class and placed at the back of her class, on a table near the 
window. 2 days later, most of the organisms had died and some had disapeared. 
What happened? What can Mdm Tan do to keep the rotting log in the same 
condition as she first found it? 

Re: What food do the organisms need on the rotting log?