2644 - CSUN ScholarWorks - California State University, Northridge

2780
Journal of Student Research Abstracts · 63
DROSOPHilA AND THE RAYS OF AGE® ULTRAVIOLET LIGHT IN SPECIFIC
RELATION TO SEX RATIO OF OFFSPRING PER EXPOSED PARENT
GENERATION.
Timothy Daniel Schroepfer, Steve DeGusta (teacher). John F. Kennedy Senior High School, 6715 Gloria
Drive, Sacramento, CA 95831.
What environmental factors account for the imbalance of male and females with in the human population?
It was the opinion of the study that ultraviolet light, a known mutagen, could cause this imbalance in the sex
ratio. The study used Drosophila melonagaster (the common fruit fly) due to it quick reproduction rate. A virgin
parent generation was exposed to 5 minutes of full spectrum ultraviolet light. They were then paired off
and left to breed. The resulting offspring of the exposed flies were then compared to control sample of normally
bred flies kept under the same conditions. The result indicated that there was not significant difference
with a chi squared calculation resulting in a p value of almost one. This indicates that the results were due to
chance variation and not due to the ultraviolet light. While ultraviolet light cannot be ruled out as a sex determinate
it can be said that the probability that it has anything to do with sex outcome is very limited.
2781
MOLD GROWTH AND ITS EFFECTS WITH WATER ON SOURDOUGH,
WHITE AND WHEAT BREAD
Brian Chan, Steve DeGusta (teacher). John F. Kennedy High School, 6715 Gloria Drive, Sacramento, CA
95831.
In this experiment I tested to see if water had an effect on the amount of mold growth on sourdough, white
and wheat bread. I hypothesized that all the bread that was watered would have more mold growth than the dry
control breads. To do. this I took 10 pieces each of white, wheat and sourdough broad and cut each slice into
four inch by four inch squares. I added 20 drops of water on each piece of bread and placed each piece of bread
in its own individual plastic zip lock bag. Almost any nutrient-rich material such as bread will go mouldy if
the environmental conditions like temperature and moisture level are suitable for mould growth. For my control
I took 10 pieces of each kind of bread and placed them in the plastic bags minus the water. After four days
mold started to grow on the bread. After seven days I took each individual piece of bread, placed a piece of
transparent graph paper over it and counted the number of squares the mold covered. I then found the area of
bread the mold covered and concluded that mold on bread with water added to it would grow faster than bread
without water. None of my control breads had any mold growth, while the watered sourdough bread had mold
growth on 1.54 cm 2 of bread, the watered white bread had mold growth on 14.21 cm 2 of bread, and the watered
wheat bread had mold growth on 19.36 cm 2 of bread. With a p-value