The objective of this experiment is to introduce students to the concept of distribution of organisms in a resource gradient and to learn the difference between kinesis and taxis. Designed for 40 students (10 groups). Duration: 2 hours or 2 lab periods. Kit contents: • Pillbugs or Sowbugs (must be ordered two weeks prior to lab)• Drosophila wild type• Sodium iodide • Sodium hydroxide • Manganese sulfate • Starch solutio: • Sodium thiosulfate• Nitrogen enrichment concentrate• Phosphorous enrichment concentrate • Instructions.