“Pulsation Rate of Blackworms” Antonio Cavazos Biology 1107- 102 (Tuesday 1:00 – 3:50) 04/ 07/ 2009 Jose Fierro Addison Rhudy I. Introduction For any animal that is too large and/or too complex a circulatory system is needed to obtain essential chemicals by the process of diffusion alone. A circulatory system transports nutrients, oxygen and other important chemicals to all body cells. This system have three components: circulating fluid, a heart or pulsating vessel in charge of pumping the fluid, and vessels through these fluids travels.
There are two types of circulatory system.
In an Open circulatory system, the vessels are open at one end allowing hemolymph fluid to flow among the cells. Most mollusks and arthropods have this type or system. In a closed circulatory system, the fluid is called blood and this fluid remains in the vessels as it circulates the body. Most vertebrates and annelids have this type of system. The purpose of this laboratory exercise was to demonstrate and explain the effects caffeine on the circulatory system of blackworms and to test the hypothesis that high concentrated caffeine ill double the heart rate pulsation of blackworms.
Blackworms have several complex systems including a closed circulatory system: a complete digestive tract: and a nervous system, including a brain and a cord. Because of the transparent skin of the blackworm, its large dorsal blood vessel is very easy to see through the microscope. Since the rate of pulsation is easily seen and calculated it’s easy to test the effects of different chemicals on their cardiovascular system. Since it’s known that caffeine increases the blood pressure one might expect that the blackworms nder the influence of caffeine will show a grater average of pulsation rate. II. Material and Methods Materials: •High concentrated caffeine •Plastic pipette •4 blackworms •Microscope •Microscope slide •2 little bowl dishes •Spring water •Chronometer Methods: 1) Fill both of the bowls with spring water to a depth of 2 cm approximately. 2) Select four worms that are equal in size. Do not pick any worms that are recently regenerated. 3) Using the plastic pipette, remove the worms from the water and place two worms per bowl. 4) Label each bowl. ) Remove a whole worm from the first bowl with the plastic pipette. 6) Place the worm on the microscope slide. 7) Remove any excess water with the plastic pipette. 8) Place the slide on the microscope and observe the worm at scanning power (4x). *Note: Use a low amount of light and avoid exposing your worms for long period of time to the light since intense light exposure can fry your worms and/or make the hyperactive. 9) Looking through the microscope, count the number of pulsations over 15 seconds. Multiply this by four to get rate per minute and record the data on the result table. 0) Return the worm to the bowl. 11) Run through steps #4-10 again using the last worm from the first bowl and record the data on the result table. 12) Using the plastic pipette, put 10 drops of the high concentrated caffeine to the second bowl and wait two minutes. 13) Remove a whole worm from the second bowl with the plastic pipette. 14) Place the worm on the microscope slide. 15) Remove any excess water with the plastic pipette. 16) Place the slide on the microscope and observe the worm at scanning power (4x) (remember to use a low amount of light). 7) Looking through the microscope, count the number of pulsations over 15 seconds. Multiply this by four to get rate per minute and record the data on the result table. 18) Return the worm to the bowl. 19) Run through steps #13-18 again using the last worm from the second bowl and record the data on the result table. 20) Get the average pulsation rate per minute from both environments (first and second bowl) and record the data on the table. 21) Analyze and compare both tables’ results to see if a chance occurred. III. Results: Table 1. Pulsation Rate for normal environment
Blackworm Number Number of Pulsations Average Pulsation Rate per Minute #1 3 12 #2 3 12 The average pulsation rate for the blackworms under a normal environment (spring water) was 12 pulsations per minute. Table 2. Pulsations Rate for Environment under the Caffeine Influence. Blackworm Number Number of Pulsations Average Pulsation Rate per Minute #1 6 24 #2 6 24 The average pulsation rate for the blackworms under the influence of caffeine was 24 pulsations per minute. Average Rate for Normal Environment: 12 Average Rate for Environment under the Caffeine Influence: 24
While the average pulsation rate per minute of the blackworms under the normal environment (spring water) was 12, the average pulsation rate of blackworms under the influence of caffeine was 24. Blackworms under the infuelnce of caffeine doubled the heart rate pulsation of the blackworms under the normal environment. IV. Discussion Since it’s known that caffeine increases the heart rate and the blood flow, the average pulsation rate for the blackworms under the influence of caffeine was expected to increase. Through this experiment, two worms in each environment were used in order to be able to etermine and compare the average pulsation rate of worms under the influence of caffeine to the control group. Since both worms exact doubled the pulsation rate of the ones on the control group one might say that accurate results were gotten. Since both, humans and blackworms have a closed circulatory system and a similar control of heartbeats one might say that caffeine will affect in a similar way to humans circulatory system. Since caffeine stimulates the body, increasing heart rate and blood pressure, and alertness, caffeine could be classified as a stimulant drug.
It was because the caffeine that the blackworms under this chemical influence environment seemed to be more alert and had greater pulsation rate than the rest of the blackworms under the normal environment. By completing this experiment, blackworms under the caffeine influence not only just increased the average pulsation rate but it doubled it compared to the blackworms under the normal environment, proving the hypothesis correct. V. Literature Cited Ratcliff, Rachel. Lab Manual: General Biology II. 2009 ed. Bohrer. Student outline. ABLE 2005 Proceedings Vol. 27. 130-136.
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