Community Ecology Lab (Instructor Materials Preparation)*

Lab Materials

This is the prep for one section of 24 students.


Ecological Succession of Bacteria in Milk

Students will do this part in table teams (groups of 4).

Materials Quantity Notes
 clean microscope slides  1 box
 coverslips  1 box
Bunsen Burner 1 per table
 tubing for Bunsen Burners  1 per table
 wire loop  1 per table
50 ml beaker 3 per table
pH probe 1 per table can use pH paper as an alternative
compound light microscope 1-2 per table
clothespins 2 per table to hold slides for gram staining procedure
gram staining kit 1 per table includes Safranin, Crystal violet, Iodine and ethanol
Bunsen striker 1 per table
squirt bottle of DI water 1 per table

Side bench for students to share: empty milk containers with nutritional information: whole milk, 2%, 1%, skim, chocolate, whole buttermilk and reduce fat buttermilk

Side bench for students to share: 1L beaker of 10% bleach solution (to disinfect slides are staining)

1 week prior to lab purchase the following:

  • Whole milk: 1 gallon (red tape)
  • 2% milk: 1/2 gallon (white tape)
  • 1% milk: 1/2 gallon (green tape)
  • Skim milk: 1/2 gallon (blue tape)
  • Chocolate milk; 1/2 gallon (brown tape)
  • Whole buttermilk: 1/2 gallon (yellow tape)
  • Reduced fat buttermilk: 1/2 gallon (orange tape)

Milk set up:

  1. Label seven 300 ml clear bottles with colors listed above.
  2. Pour 100 ml of each milk type intwo their respective bottles
  3. Place bottles on a cart in the prep area until the first lab
  4. Repeat steps 1-3 each day until the last day of the lab
  5. At the end of the two week there should be a total of 70 labeld bottles

Milk in incubator (should be set at 37 C)

  1. Obtain one 300 ml clear glass bottl
  2. Pour 100 ml of whole milk into the bottl and place in the incubator (whole milk is the only type to go in the incubator)
  3. Repeat steps 1-2 each day until the last day of this lab
  4. At the end of the two week period there should be a total of 10 labeled bottles