Lights Out Student Research Program The Science House Biological Clocks By: Brandon Scotton & Curtis Grayson

Abstract In this experiment, we took different strains of Chlamydomonas, which is algae, and observed how each one reacted when placed in the light and the dark. We used a phototaxis to determine which strain went to the light or remained neutral. After seeing which strains swam to the light, we put those in the dark. The ones that remained neutral were left in the light. After leaving the Chlamydomonas in their certain area for about a week, we observed most of the strains became complete opposite. Most of the strains that were placed in the dark for a week became neutral in the phototaxis chamber. One of the strains that was left out in the light moved toward the light when it was put in the chamber. We concluded from this experiment that these strains of Chlamydomonas are mainly found in well-lit areas and are rarely found in darker areas.

Background Information Criteria for phototaxis Dark Room Chlamydomonas are very light sensitive. Light tight room All extraneous light sources should be masked with red acetate barrier filters. The room should also be well vented.

Purpose To determine how different strains of Chlamydomonas reacted under different circumstances. To determine how the strains of Chlamydomonas that swam to the light in the phototaxis chamber reacted in the dark.

Materials 1 Phototaxis chamber 7 different strains of Chlamydomonas algae 1 liter of water, salts solution, phosphate solution and trace elements mixed thoroughly Fluorescent lights Microscope cover slip trash bag

Procedure 1. Build the phototaxis chamber 2. Mix 1 liter containing 5 ml salts solution, 5 ml phosphate solution, 1 ml trace elements solution and water 3. Test the strains of Chlamydomonas in the phototaxis chamber to see which ones swam to the light 4. Record data

STRAINS OF CHLAMYDOMONAS 1. CC-124 wild type mt - 2. CC-125 wild type mt + 3. CC-1036 pf18 mt + 4. CC-1101 eyl mt - 5. CC-2679 mbol mt + 6. CC-2894 ptx 1 7. CC-2990 neg 1

Data (Before switch) StrainsLightNeutralDark 1. x 2. x 3. x 4. x 5. x 6. x 7. x

Data (After switch) StrainsLightNeutralDark 1. x 2. x 3. x 4. x 5. x 6. x 7. x

Analysis It turns out that most of the strains of Chlamydomonas that were placed in the dark became neutral when we put them back in the phototaxis chamber. One of the neutral strains that was left in the light for a week swam toward light when it was put in the phototaxis chamber. One of the strains that was put in the dark actually moved away from the light when it was in the phototaxis chamber. This was very interesting to me.

Conclusion What we concluded from this experiment was that these strains of Chlamydomonas are mainly found in well- lit areas. Theses types of algae are never really found in darker areas in bodies of water. When the strains changed the way they did after the week,we were very surprised to see this transformation. We actually thought that these strains would have stayed in the same position. But it turns out that we were proven wrong.