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Unformatted text preview: Group Members: _________________________________________________Exercise_______Date: ___________ LI ______________________ Unique __________ Day: __________ Room: _______ Lab Start Time ________ Exercise 9 Analysis To be completed as a group and turned in at the beginning of your next laboratory period. Include your “Data & Results”, sketches, acquired digital images, etc. as directed by your laboratory instructor. Show your work for all calculations and/or print your MS Excel â data sheets. Be sure to include proper units where necessary. Adhere to University’s Honor Code and course policies. Balance between brevity and completeness. 1. Make a 2D line graph using MS Excel of the results you obtained in this exercise. Indicate One the horizontal axis, indicate the 5-minute time intervals for the duration of the exercise. One vertical axis, indicate dissolved oxygen levels (concentration in mg/L) throughout the range at which they were measured. On the other vertical axis, indicate ventilation rate as measured as water volumes collected over time (mL / min) throughout the range at which rates were measured. Plot the data for ventilation rate and oxygen concentration, connecting the data points for each with straight lines. On attached sheet. 2. Demonstrate your understanding of crayfish physiological responses to dissolved oxygen concentration by answering the following with regard to your graph complete in question #1: a. What was the immediate response in crayfish ventilation rate to the initial decrease in O2 concentration? There was an increase in ventilation rate , because with a decrease in O2 concentration , the crayfish answers by ventilating faster to keep the O2 at a desirable level. b. What was the extended response in crayfish ventilation rate to the sustained low O2 concentration? There was a decrease in ventilation rate because our crayfish had a small surface area, and needs much less oxygen than bigger crayfish for its organs to function. c. There are two periods of high oxygen concentration in this experiment. Compare the data gathered during the two periods – were the ventilation rate similar or different? As volume of water passing over the gills increases, the available O2 increases so yes the ventilation rates were relatively similar and at a slower rate. After the low oxygen concentration, it did take a few minutes for the amount of water pumped to decrease, but it did eventually become similar to the water ventilated during the initial high oxygen concentration. d. Suggest an explanation - what might the cause(s) of any similarities or differences you observed? Oxygen sensors in crayfish ventilate slower as O2 levels increase, and within both periods the crayfish ventilated slower. With increased O2 levels the crayfish responds by ventilating slower to keep desirable levels of O2 in the crayfish for it to survive and it organs to function....
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This note was uploaded on 04/04/2012 for the course ECO 304K taught by Professor Hickenbottom during the Spring '10 term at University of Texas.
- Spring '10