Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
VCO 2 /VO 2 = 1.0 during the oxidation of carbohydrates
(Suarez, Lighton, Joos, Roberts, & Harrison, 1996) as
illustrated from the balanced chemical equation:
C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O
Masses of eight roaches were taken before
each test proceeded to make body mass comparable to
metabolic rate for three variables: room temperature,
heat, and cold-induced environments. Conditions were
kept similar under each test, such as leaving the
roaches exposed to light to deter them from changing
basal to resting metabolism, where the MR would be
lower in the latter.
The average metabolic rates from each of the
separate temperature trials were found to have a
combined p-value that is lower than each of the pairs.
There are no significant differences (p-values > 0.05)
between any of the three variables. A large p-value
indicates the difference in results probably happened
by chance and that the hypothesis is not accepted. The
null hypothesis stating there is no association of
temperature on metabolic rate is considered valid, and
the alternative hypothesis stating there is a significant
difference between the MRs of the three variables is
rejected. Therefore, temperature and MR of G.
portentosa are independent.
A possible reasoning for this result is due to the fact
that cockroaches are homeothermic ectotherms,
allowing the roaches to change their body temperature
and better adjust to the environment that they are
placed in. Their ability to adapt to a diversity of
conditions may be attributed to the millions of years of
evolution and being selected to new environments.
Though there is no significant association
between temperature and MR, R 2 values of the graphs
display a relatively strong correlation (average
0.9556) between the concentration of CO 2 and time,
demonstrating a pattern where CO 2 and time is directly
related: over time, CO 2 production increases within the
trials of all three temperatures though MRs remains
constant (Figure 3).
Possible sources of error may include short
time frames of data collection, a small sample size, and
faulty equipment setup. The sample size tested was
only 8 cockroaches while a larger sample size would
have given a better understanding of the species as a
whole. The test was conducted for a 15-25 minute time
frame; the short breadth of this trail period may not
have given the subjects enough time to acclimate to the
surroundings and thus give inaccurate readings. During
the high temperature trial, two separate incubators were
used; the second had a less precise way of controlling
the temperature which could have lead to inconsistent
temperature conditions. Also one of the Xplorer GLX
CO 2 detectors went into power-saving mode after a
short period and shut off before the completion of
timed trials, making the sample size of CO 2 production
smaller than it should have been. An undersized
amount of data collection could have lead to a less
precise mean MR for the entire group for that trial.
Another possibility is that during testing, a CO 2 sensor
probe may not have been sealed completely to the
container, remaining slightly ajar as to allow a higher
concentration of CO 2 produced by a roach in the
chamber to diffuse out into the surroundings.
Studying insect metabolism gives a stronger
understanding of the Kingdom Animalia and more
specifically the subphylum Insecta. This information
can be used in future experiments if the subject chosen
is cockroaches, but tested under a separate variable
instead of temperature. In addition, it could give
examples of small organisms’ metabolic rates and to
see if their results are within reasonable parameters or
not.
Literature Cited
Dudley, R. (2000). The biomechanics of insect flight:
form, function, evolution. Princeton University Press.
Gillooly, J.F. (2001). Effects of size and temperature
on metabolic rate. Science 293. 2248.
Hails, C.J. (1983). The metabolic rate of tropical birds.
Condor 85. 61-65.
Mueller, P. & Diamond, J. (2001). Physiology.
Metabolic rate and environmental productivity: Wellprovisioned
animals evolved to run and idle fast.
Proceedings of the National Academy of Sciences of
the United State of America, Vol. 98, No. 22. 12550-
12554.
Suarez, R.K., Lighton, J.R.B., Joos, B., Roberts, S.P.,
& Harrison, J.F. (1996). Physiology. Energy
metabolism, enzymatic flux capacities, and metabolic
flux rates in flying honeybees. Proc. Natl. Acad. Sci.
USA, Vol. 93. 12616-12620.
Weins, A. & Gilbert, L. (1995). Biological sciences.
Regulation of cockroach fat body metabolism by the
Corpus Cardiacum in vitro. Science 29, Vol. 150, No.
3969. 614-615.
The Effect of Creatine Monohydrate on the Run Time of Sceloporus occidentalis
Dayana Vera and Michael Moeller
47
Saddleback Journal of Biology
Spring 2008