In the experiment, we will establish microcosms to test the effect of illumination on relative abundance of our two ciliate phenotypes. You will use 3 beakers filled with water, and will inoculate these beakers with a mixed culture containing both phenotypes. Inoculation will involve adding a small volume of the culture to the beakers, permitting the ciliate population to grow in this new environment.
You will determine the initial relative abundance of each of the two Paramecium species in the mixed culture. Do this by making a wet mount slide of the mixed culture and observing it under the microscope. Observe many fields of view and count the number of each species you see. Then use this to calculate the relative abundance (proportion of the total) for each species. Write your observations on the board at the front of the lab. Once everyone has completed this, you will calculate a class average relative abundance (based on all student observations).
After inoculation, you will label your beakers. One will be incubated in the dark, one will be incubated under white light, and one will be incubated under green light. Periodically, the ciliates will be fed with a culture of bacteria.