Exercise Lab 2 - Scientific Method

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Exercise Lab 2: Scientific Method Exercise 1: Use of Human Subjects in Research You just filled out a survey and were asked if you would like to provide your answers to a researcher. To put it another way, you were just asked to be a research subject. Let us take a moment to reflect on using humans in research. Directions : Answer the following questions (a) While you had to fill out the survey, you were able to choose whether or not to provide your answers to a researcher. This is an example of asking for consent from human subjects. Why is this important? Asking for consent from human subjects is important because it respects our autonomy and protects our rights. It gives us the freedom to decide whether or not to participate in research, and it ensures that we are not being coerced or manipulated. In the example of the survey, I was able to choose whether or not to provide my answers to the researcher. This gave me control over my own data and protected me from any potential harm that could come from participating in the research. (b) When the survey was presented, it was explained to you how your information would be used, if you chose to participate. This is an example of informed consent. What were two pieces of information you learned that helped you make an informed choice as to whether you would participate? Informed consent is important because it gives human subjects the information they need to make an informed decision about whether or not to participate in research. The information should include the purpose of the research, the procedures that will be used, the risks and benefits of participation, and the subject's right to withdraw from the research at any time. In the example of the survey, I was told how the information would be used. This helped me to understand the potential risks and benefits of participating in the research, and it allowed me to make an informed decision about whether or not to provide the answers.

(c) When we use human subjects, it is important that we do not coerce participation. Suppose we gave 10 bonus points to every student who agreed to participate. How would this be coercive? Coercion is important to avoid in research because it can lead to subjects making decisions that are not in our own best interests. Coercion can take many forms, but it generally involves using threats or intimidation to get someone to do something that they would not otherwise do. In the example of the survey, it would be coercive to give students bonus points for participating in the research. This would put pressure on students to participate, even if they were not comfortable doing so. Exercise 2: Pipetting This semester you will be using three types of pipettes. 1. Disposable pipettes which you used last week and are handy for catching copepods. 2. Volumetric pipettes which you will use to measure things like water for your wells. 3. Micropipettes which you will use to feed your copepods. A. How to use a volumetric pipette The pipette works in similar fashion to a straw that allows fluid to be sucked up in one end. (NEVER put your mouth on the pipette!!!) You will use a pipette pump to suck up the correct

amount of fluid and then push that fluid back down the pipette into a new solution. Today, you will start by learning how to use the pipette. 1. Obtain a weigh boat. 2. Obtain a 5ml pipette. 3. Obtain the appropriate pipette pump for the 5ml pipette. Pipette pumps differ in size and are designed for specific pipettes, so be sure you have the right one. 4. Place the proper pipette pump on the top of the pipette. Do NOT push on the end of the pipette, as this is an easy way to stab yourself in the hand with glass. 5. Place the weigh boat on the scale and tare (or zero) it. 6. Measure out exactly 1ml of water into the weigh boat and weigh it. 7. Record your results below and check with your TA to test your accuracy. 8. Repeat the process two times to check your accuracy. Record your results below. If your weights are not similar, repeat until you can accurately measure 1ml of water. Each member of the group must complete this process individually . Weight of 1ml of water Attempt # Weight 1 1.03 2 1.01 B. How to use a micropipette Micropipettes are used to measure more accurately and can measure very small amounts of liquid. Volumetric pipettes measure in milli liters. Micropipettes measure in micro liters. The top of a micropipette will usually tell you the maximum amount of liquid that it can accurately measure. (Sometimes it tells you the maximum and minimum.)

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For example, this picture here indicates that the pipette on the far left can pipette up to 1,000 microliters, center can go up to 200 microliters, and the one on the right up to 20 microliters. Micropipettes need tips! You should never use a micropipette without first putting on a tip!! 1. Obtain a P-200 micropipette 2. Push the end of the pipette onto a pipette tip located on your table. 3. Choose an amount you want to pipette between 100-200 microliters. 4. Turn the dials/wheels near the top of the pipette until you reach your chosen number. 5. Place the tip into the water on your table. 6. With the tip in the water, gently press down on the top button until you feel it come to the first stop. 7. With the tip still in the water, release the top button. 8. Now place your micropipette over a petri dish. Pushing gently on the top button, release the water onto the petri dish. 9. Repeat this process a second time, choosing an amount between 20-100 microliters. Record your results. Trial 1 : Amount I chose to pipette (in microliters): 150 Size of my droplet (draw size of droplet):

Trial 2 : Amount I chose to pipette (in microliters): 50 Size of my droplet (draw size of droplet): Exercise 3: Making Observations and Developing Hypotheses One critical step in the scientific method is to gather information from the literature and use it to develop new and testable hypotheses. This reading of the scientific literature is one means of making observations. Rather than making the observations directly in the lab or field, you are observing what others have done and then building on it. Directions: In this exercise, you will need to read the following and create one valid hypotheses based on the information presented. Remember, a hypothesis is not your research question, but what you think the answer to your question will be. This may be easier if you work with your group members!! 1. The mating behavior of male organisms is strongly influenced by the reproductive biology of conspecific females. Of particular importance to the male are the timing of the female’s receptivity to mating, her capacity to store sperm (keep sperm viable in her body for prolonged periods of time), and the probability of successful sperm displacement (removing sperm from the female’s body) by future matings of the female with other males. Among crustaceans, male mating behavior frequently involves a period of time during which a male clasps a female without actively attempting copulation (the pre-copulatory “passive” phase of Parker, 1970); during this period, which may last a week or more, a male cannot inseminate a female other than the one he is holding. (modified from Burton, 1985). Briefly list 3 facts you learned from this paragraph 1. Male organisms' mating behavior is strongly influenced by conspecific females' reproductive biology.

2. Important factors for males include the timing of female receptivity, her sperm storage capacity, and the probability of successful sperm displacement. 3. Among crustaceans, there is a pre-copulatory "passive" phase during which a male clasps a female without actively attempting copulation. Thinking about these facts, write one question that you have. "How does the duration of the pre-copulatory 'passive' phase in crustaceans affect the success of male insemination and sperm displacement?" What do you think the answer to this question might be? Write this out as a hypothesis: A hypothesis based on the question might be: "If the duration of the pre-copulatory 'passive' phase in crustaceans is extended, then the success of male insemination and sperm displacement will increase, as prolonged clasping allows for a higher probability of successful copulation and sperm displacement." 2. Tigriopus californicus is a harpacticoid copepod found in small upper tidepools along rocky areas of the west coast of North America (Ricketts et al, 1968). Occupying this habitat, the copepod is exposed to relatively large and sometimes sudden changes in seawater concentration due to evaporation or dilution of the media (Kontogiannis, 1973). In response to this stress, Tigriopus has evolved adaptive mechanisms allowing it to survive over a wide range of salinities. Survival and reproduction have been observed at salinities between 21.2 and 75.3 parts per thousand under laboratory conditions (Huizinga, 1971). (McDonough and Stiffler, 1981). Briefly list 3 facts you learned from this paragraph 1. Tigriopus californicus is a harpacticoid copepod found in small upper tidepools along rocky areas of the west coast of North America. 2. The copepod is exposed to significant changes in seawater concentration in its habitat due to evaporation or dilution of the media. 3. Tigriopus has evolved adaptive mechanisms to survive a wide range of salinities, with observed survival and reproduction between 21.2 and 75.3 parts per thousand under laboratory conditions.

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Thinking about these facts, write one question that you have. How does Tigriopus californicus adapt to and survive in tidepool environments with varying salinities? What do you think the answer to this question might be? Write this out as a hypothesis . If Tigriopus californicus has evolved adaptive mechanisms to regulate osmotic balance, then it will demonstrate enhanced survival and reproductive success in tidepool environments with fluctuating salinities, allowing for a broader range of salinity tolerance compared to copepods without such mechanisms. Exercise 4 : Determining the Validity of Hypotheses Directions : Read over the following hypotheses to determine if they are testable . If not, explain why not . 1. Glucosamine supplements reduce joint pain in elderly human patients. This hypothesis is testable. You can conduct a controlled study comparing a group of elderly patients taking glucosamine supplements with a control group not taking the supplements to assess the impact on joint pain. 2. Retinal cream A reduces the depth of wrinkles around the eyes. This hypothesis is testable. You can conduct a controlled experiment where individuals use retinal cream A, and their changes in wrinkle depth are compared to a control group using a placebo or another cream. 3. Dogs with long hair prefer cooler climates. This hypothesis is not testable. It's challenging to measure a dog's preference for climate objectively. Preferences are subjective and can't be accurately determined without clear behavioral indicators. 4. The higher the intelligence of the horse, the easier it is to train it to jump over obstacles.

This hypothesis is testable. You can design a study to assess the correlation between a horse's intelligence and its ability to be trained in jumping over obstacles. Intelligence can be measured, and training success can be objectively evaluated. 5. High-fat, high-sodium diets for humans increase the risk of atherosclerosis (hardening of the arteries). This hypothesis is testable. Controlled studies can be conducted to compare the incidence of atherosclerosis in individuals with high-fat, high-sodium diets to those with healthier dietary patterns. The outcomes can be measured to determine if there is a correlation. 6. Tyrannosaurus rex could not digest the citric acid in lemons. This hypothesis is not testable because it refers to a specific claim about the digestive capabilities of an extinct species, and we cannot directly observe or experimentally test the digestive system of a Tyrannosaurus rex. Exercise 5: Understanding Experimental Design Directions : For each experiment, answer the questions about the experimental design. Experiment 1 : A researcher is studying the effect of the pesticide Cypermethrin on the survival of juvenile salmon in the laboratory. He has 100 salmon in a solution of 10mg/L of cypermethrin for 96 hours and measures their survival, which was 87%. He then places another 100 salmon in 100mg/L of cypermethrin for 96 hours and measures their survival, which was 52%. He concludes that Cypermethrin levels should be regulated to be less than 10mg/L in waterways where salmon are found. Independent variable: The concentration of Cypermethrin in the water (two levels: 10mg/L and 100mg/L).

Dependent variable(s): Survival rate of juvenile salmon. What other variables should they standardize?  Other environmental conditions such as temperature, pH, and light exposure.  The size, age, and health of the juvenile salmon. Control group: A group of juvenile salmon not exposed to Cypermethrin or exposed to a negligible concentration. Experimental group(s): Two experimental groups exposed to different concentrations of Cypermethrin (10mg/L and 100mg/L). What are two strengths of his experimental design? Controlled Variables Multiple Concentrations What are two weaknesses of his experimental design? Lack of Dose-Response Curve Short Exposure Duration Exercise 6 (Reflection and Planning) As a group in your shared document fill out the following: Group Reflection : 1. What went well

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2. What could use improvement and how? Group planning : To Do By Who

Exercise Lab 2 - Scientific Method

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