The basis for this game is the O-Deer concept, however it is modified and simplified for my 6th grade science classes, and worked good in my 8th grade class as well.
This is a 2 day activity and lab
Teacher reviews what is needed in an ecosystem and the rules of the game.
Students do the activity, in 3 groups staged in 3 lines.
They do this in a form of tag.
Teacher records the population changes of the deer and coyotes over time.
Data is recorded for 20 rounds but you can do more.
The lab/activity write-up
Students answer questions about how the population changed over time.
Students also create a line graph using the two recorded populations of deer and coyote and analyze the results.
Students really enjoy the activity and like that the data they are using in the write-up is their own.
The copy you will receive will have 2 different graphs for the students to use one that they need to decide the scale and another simpler one for lower grades that already has the scale on it.
During the game be sure to pause and have the students predict what will happen to the different populations when they get unbalanced.