Science dependence of Man on the environment
Lab 1 – Introduction to Science
Exercise 1: The Scientific Method
Dissolved oxygen is oxygen that is trapped in a fluid, such as water. Since many living organisms require oxygen to survive, it is a necessary component of water systems such as streams, lakes, and rivers in order to support aquatic life. The dissolved oxygen is measured in units of parts per million (ppm). Examine the data in Table 4 showing the amount of dissolved oxygen present and the number of fish observed in the body of water the sample was taken from and then answer the questions below.
1. Make an observation – Based on the data in Table 4, describe the relationship between dissolved oxygen content and fish populations in the body of water. Discuss the pattern observed in the data set.
Answer = Examining the data in Table 4, it is clear that there are no fish observed under zero dissolved oxygen (DO). As the level of dissolved oxygen increases, so does the number of fish. However, this relationship changes from the 12 ppm point after which each increase in DO level results into an irregular drop in the fish populations.
2. Do background research – Utilizing at least one scholarly source, describe how variations in dissolved oxygen content in a body of water can affect fish populations.
Answer = According to Yovita J. Mallya, oxygen depletion (hypoxia) is highly detrimental not only to fish but other aquatic organisms in a particular system (Y.J. Mallya, 2007). For this phenomenon – popularly referred to as anaerobic – to occur, the DO concentration must drop to between 1 and 30 percent. Most fish can hardly survive in this range since an ideal aquatic environment should experience a DO concentration of over 80 percent. However, if the water holds a very high saturation of oxygen (greater than 100 percent), then the phenomenon is called hyperoxia and very few fish can thrive in such a state.
3. Construct a hypothesis – Based on your observation in Question 1 and your background research in Question 2, develop a hypothesis statement that addresses the relationship between dissolved oxygen in the water sample and the number of fish observed in the body of water.
Answer = From the analysis above, both too high and too low dissolved oxygen levels can prove detrimental to fish life. Apparently, this explains why the fish populations in the water sample grew as the level of oxygen level increased after which the number began dropping as the DO concerntration surpassed the 12 ppm mark.
4. Test with an experiment – Describe an experiment that would allow you to test your hypothesis from question 3. This description must provide ample detail to show knowledge of experimental design and should list the independent and dependent variables, as well as your control.
Answer = To experiment this, set up a small fish tank and use a tester to record the level of dissolved oxygen in the water before introducing any fish. Using 10 fishes, measure and record the average DO level after every five minutes a fish is introduced in the tank. Change the water and repeat the experiment but introduce all the fish into the tank at the same time. Using an aquarium air pump to replenish oxygen in the water, observe and record how many fish are gasping at the surface and how many remain active after each unit increase in DO level on your tester. In this case, let the number of fish would be the dependent variable whereas the DO recorded would be the independent variable.
5. Analyze results – Assume that your experiment produces results identical to those seen in Table 4, what type of graph would be appropriate for displaying the data and why?
Answer = Assuming the results obtained are identical to those in Table 4, a line graph can best display the data since the fish populations (in the controlled experiment) drop irregularly. Besides being easy to read, the graph clearly provides the pattern in data thanks to the specific variables. From this, the trend can be predicted to make an accurate conclusion.
6. Analyze results – Graph the data from Table 4 and describe what your graph looks like (you do not have to submit a picture of the actual graph).
Answer = With the y-axis labelled “number of fish”, the values are plotted originating from 0 to 16 with a range of two between the values. With similar range between individual values, the x-axis is tagged “dissolved oxygen level (in ppm)” with calibrations from 0 to 20. The line graph connects points corresponding to the number of fish against the change in DO level with the highest data point being the 12,15 markers.
7. Draw conclusions – Interpret the data from the graph made in Question 6. What conclusions can you make based on the results of this graph?
Answer = From the graph, an increase in the level of DO results in a similar effect on the number of fish surviving in the sample water. With the highest number of fish recorded when DO level is 12 ppm, the populations begin declining as the water becomes more saturated with oxygen. This shows that both too high and too low DO levels prove detrimental to aquatic invertebrates.
8. Draw conclusions – Assuming that your experiment produced results identical to those seen in Table 4, would you reject or accept the hypothesis that you produced in question 3? Explain how you determined this.
Answer = Upon analysing the data presented in the line graph above, a valid conclusion can be drawn that low concertntration of dissolved oxygen can lead to fish kills. Similarly, high levels of DO can seriously compromise the quality of water thereupon impacting negatively on fish life. Scientific research shows that apart from dissolved oxygen, other parameters like temperature and salinity of water can also affect the number and type of fish in a certain body of water (Matthews, 2012).
Helfman, G. S. (2009). The diversity of fishes : biology, evolution, and ecology. New Jersey: Chichester, UK ; Hoboken, NJ : Blackwell.
Matthews, W. J. (2012). Patterns in Freshwater Fish Ecology. New York: Springer Science & Business Media.
Carefully review the Grading Rubric before beginning the assignment.
Read “Lab 3: Biodiversity.” This lab will allow you to investigate how various organisms alter their environments. Additionally, it will allow you to assess the health of ecosystems based upon their biodiversity. Then, you will utilize this information and your eScience lab kit to complete Demonstration 1 and Experiment 1 on the Week Three Lab Reporting Form. Make sure to complete all of the following items before submission:
a. Read through the introductory material.
b. Perform Demonstration 1: Interdependence of Species using your eScience lab manual and kit.
c. Complete Table 1 and answer Post Lab Questions 1 through 3 in complete sentences on the Week Three Lab Reporting Form.
d. Record your hypothesis for Experiment 1 on the Week Three Lab Reporting Form.
e. Complete Experiment 1: Diversity of Plants using your eScience lab manual and kit.
f. Complete Table 2 and answer Post Lab Questions 1 through 4 in complete sentences on the Week Three Lab Reporting Form.
Submit the Week Three Lab Reporting Form via Waypoint. The document does not need to include a title page or other APA formatting; however, any outside sources utilized in your answers must be referenced in proper APA format as outlined in the Ashford Writing Center.
Late Policy: Written assignments (essays, journals, presentations) are due on the specified days in the course. Written assignments will be subject to a late penalty of up to 10% per day up to three days late. If written assignments are submitted after 72 hours past the due date, instructors can give a penalty up to and including a grade of 0 for the assignment.