Introduction:
As with all living things, fish need oxygen in order to live. Fish have specialized organs called gills that are used to extract dissolved oxygen from water. In order to be able to extract the oxygen from water fish take in water through their mouths. This water is then forced into the gills. Gills are rich in blood vessels and have very thin walls. As the water passes through them, oxygen in the water is transferred through the thin walls to the blood stream. This oxygen is then transferred to cells.
Purpose:
The purpose of the experiment is to determine the effect that the temperature of water has on the respiration rate of a fish. Since fish are cold-blooded animals, it would be important to determine the effect that water temperature has on their breathing rates.
Materials and method:
For this experiment, a 250 ml beaker was used. The beaker was filled with 150ml aquarium water and a goldfish was put in the beaker. A thermometer was used to determine the initial water temperature. This value was recorded. After giving the fish three minutes to acclimatize to its environment its breathing rate was determined. The number of breaths that the breath took were then counted for a minute. This was achieved using a stopwatch. The number of breaths were determined as the number of times that the fish opened its mouth. This data was recorded and ice was added to the beaker to lower the water temperature by 2 degrees. Ice was then used to lower the temperature of the water containing the goldfish. In order to ensure that the fish was safe temperatures were slowly lowered in two-degree decrements. A stirring rod was used to ensure consistent water temperature and a thermometer was used to ensure that the desired 2-degree drop was achieved. Once this was completed the process of giving the fish three minutes and counting the number of breaths for a minute was repeated. This process was then repeated until a final temperature of 10 OC was reached.
Results:
Data collected from the six groups is as shown in table 1 below. It is clear from the table that the groups did not attain the same results at any given temperature. However, a clear trend is evident from the data. It is clear that for all the groups that the breathing rate reduced with a reduction in water temperature. This indicates that breathing rate and water temperature are directly proportional to each other.
Works Cited:
Fernandes, Marisa N. Fish Respiration and Environment. Enfield, N.H. [u.a.: Science Publ, 2007. Print.
Schmidt-Nielsen, Knut. Animal Physiology: Adaptation and Environment. Cambridge: Cambridge University Press, 2007. Print.
Perry, Steve F, and Bruce L. Tufts. Fish Respiration. San Diego, Calif: Academic Press, 1998. Internet resource.
Figures:
Chart 1: Results obtained by group 1
Chart 2: Results obtained by group 2
Chart 3: Results obtained by group 3
Chart 1: Results obtained by group 4
Chart 5: Results obtained by group 5
Chart 6: Results obtained by group 6
