Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
1. THE EFFECT OF SODIUM CHLORIDE CONCENTRATION ON THE GROWTH OF THE
COMMON BEAN (Phaseolus vulgaris). Alexandra M. Franco and Earl-Eugene E. Ringpis.
Department of Chemistry, Saddleback College, Mission Viejo, California 92692.
The majority of plants, including most crop plants, are glycophytes, which can only tolerate relatively
small amounts of salt in the soil from which they grow. It is not expected that glycophytes will tolerate
increases in salt concentration due to the resultant cellular water loss. Therefore, we hypothesized a
negative, nonlinear relationship between salinity and growth in the glycophyte Phaseolus vulgaris. We
tested the effect of increasing NaCl concentration on the growth of the common bean, P. vulgaris. Each
of eight plant groups (N group = 3) was watered every 48 hours with 15 mL of a specific saltwater solution
containing a different NaCl concentration (0.00% - 3.03% NaCl) over an experimental period of seventeen
days (N = 24). Plant survival was significantly reduced when salinity was 1.68% and higher. The only
experimental group to remain unaffected by its salt concentration was the group watered with a 0.20%
NaCl solution. Each plant was measured for dry mass at the end of the experiment. Plant growth was
significantly affected, and the effect of the increasing salt concentrations on growth produced a negative,
nonlinear trend (R 2 = 0.212, F 1, 22 = 5.93, p-value = 0.023, linear regression). These results indicate a low
salt-tolerance in P. vulgaris, thus supporting our hypothesis.
2. PREFERENCE OF DOGS (Canis familiaris) FOR HIGH FAT DOG FOOD VERSUS LOW FAT DOG
FOOD Chris J. LaCroix and Jocelyn A. Finley. Department of Biological Sciences, Saddleback College,
Mission Viejo, California 92692
The general purpose of this study was to discover if Canis familiaris, the common domestic dog, has a
preference of high fat dog food over a low fat dog food. The high fat dog food chosen had a minimum of
17% crude fat, while the low fat dog food had a labeled 6% crude fat content. The dogs were tested in a
period of three trials, in which the time was recorded on how long it took the dog to favor one food over
the other. After each trail was concluded, a twenty minute recess was given to reset the dogs mind about
the food he or she had just received. The average time for the seven dogs to favor the high fat dog food
over the low fat dog food was 4 minutes and 14 seconds. After collecting data, the discovered conclusion
was that dogs actually favor a high fat dog food over a low fat; in addition, C. familiaris can distinguish
between the two when presented with both at the same time.
3. TESTING FOR INTELLIGENCE IN THE SLIME MOLD Physarum polycephalum Raiff Josey and
Christopher Luna. Department of Biological Sciences, Saddleback College, Mission Viejo, California
92692
Intelligence has only ever been associated with a relatively small list of multicellular animals, and for
plants, it is a debate between calling their behaviors intelligence or thoughtless instinct. The slime mold,
Physarum polycephalum, an amoeboid organism, was tested for intelligence in an attempted replication
of a 2000 experiment in which the Physarum polycephalum was “run” through a plastic maze atop a plate
of plain agar gel between two agar blocks of oat nutrient. According to the 2000 experiment, the
Physarum polycephalum is not only capable of navigating the maze, but “chose” the shortest route out of
four possible, connecting the two agar blocks of oat nutrient, thus expressing a form of intelligence. Our
hypothesis predicted that the slime mold would select one of the four routes between the two agar blocks
of oat nutrient, thus displaying as the 2000 experiment did, that the slime mold expresses intelligence.
However, due to the inadequate placement of Physarum polycephalum in the agar gel mazes, the slime
mold did not interconnect to itself; therefore, it did not select any of the available routes between the two
agar nutrient blocks. The failure of the slime mold to connect and “choose” a route between the agar gel
nutrient blocks failed to yield any data that would allow us to test our hypothesis.
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Saddleback Journal of Biology
Spring 2008