This fun activity I complete with my students during my ecosystem unit. After our discussion of producers, consumers and decomposers, I pass out the worksheets. Students work with a partner to classify, cut and paste the pictures onto the chart. When all have finished, I have groups come to the smartboard and drag a picture into the appropriate column. You could also do the drag activity first and then pick up the cut and paste activity for assessment. The kids really enjoy it. It's not too hard, yet not too easy.