Scientific Method Review. 3. State two factors that should be kept constant.

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1 Name: Date: 1. Base your answer(s) to the following question(s) on the information, diagram, table, and on your knowledge of biology. A student wanted to test the hypothesis that rooting hormones will stimulate the production of new roots at a faster rate than would take place without rooting hormones. Two stem cuttings of equal length, similar to the one shown below, were taken from a rose, a begonia, and a geranium plant. 2. Base your answer(s) to the following question(s) on the provided information. Acid rain can have a ph between 1.5 and 5.0. The effect of acid rain on the environment depends on the ph of the rain and the characteristics of the environment. It appears that acid rain has a negative effect on plants. The scale below shows the ph of normal rain. The cut end of one cutting from each plant was dipped into the hormone and then planted in wet sand. The other cutting from each plant was planted in wet sand without dipping it into the hormone. All cuttings were maintained in identical environmental conditions. At the end of 4 weeks, all the cuttings were removed from the sand and the lengths of the roots that had developed were measured. The results are summarized in the data table below. Provide the information requested below that should be included in a research plan to test the effect of ph on the early growth of bean plants in the laboratory. Identify the independent variable. 3. State two factors that should be kept constant. Describe one way the student could make the experiment more valid. 4. A television advertisement claims that a certain brand of cough drop reduces coughing for 8 hours. Describe an investigation that could be used to determine if this claim is valid. In your answer, include at least a description of: the treatment to be given to the experimental group the treatment to be given to the control group the data to be collected when the data should be collected one observation that would lead to the conclusion that the claim is valid page 1

2 5. Plants respond to their environment in many different ways. Design a controlled experiment to test the effect of one environmental factor (such as light, acidity of precipitation, etc.) on some aspect of plant growth. In your experimental design be sure to: state the hypothesis list the steps of the procedure identify the control setup for the experiment include an appropriate data table with column headings for the collection of data identify the independent variable in the experiment 7. The drugs usually used to treat high blood pressure do not affect blood vessels in the lungs. Bosentan is a new drug being studied as a treatment for high blood pressure in the lungs. In an experiment, patients treated with bosentan showed an improvement in the distance they could walk without fatigue within 12 weeks. Design an experiment to test the effectiveness of bosentan as a drug to treat high blood pressure in the lungs. In your answer be sure to: state the hypothesis your experiment will test state how the control group will be treated differently from the experimental group state two factors that must be kept the same in both the experimental and control groups state the type of data that should be collected to determine if the hypothesis is supported 6. On a television talk show, a guest claims that people who exercise vigorously for 15 minutes or more every day are able to solve math problems more rapidly than people who have no vigorous exercise in their daily routine. Describe a controlled experiment that could be conducted to test this claim. In your description be sure to: state the purpose of the experiment state why the sample to be used should be large describe how the experimental group will be treated and how the control group will be treated state the specific data to be collected during the experiment state one way to determine if the results support the claim 8. The diagram below shows how a coverslip should be lowered onto some single-celled organisms during the preparation of a wet mount. Why is this a preferred procedure? A. The coverslip will prevent the slide from breaking. B. The organisms will be more evenly distributed. C. The possibility of breaking the coverslip is reduced. D. The possibility of trapping air bubbles is reduced. page 2

3 9. Which statement about the use of independent variables in controlled experiments is correct? A. A different independent variable must be used each time an experiment is repeated. B. The independent variables must involve time. C. Only one independent variable is used for each experiment. D. The independent variables state the problem being tested. 12. The current knowledge concerning cells is the result of the investigations and observations of many scientists. The work of these scientists forms a well-accepted body of knowledge about cells. This body of knowledge is an example of a A. hypothesis B. controlled experiment C. theory D. research plan 10. In an investigation to determine a factor that affects the growth of rats, a student exposed 100 rats of the same age and species to identical conditions, except for the amount of living space and the amount of food each rat received. Each day the student measured and recorded the weight of each rat. State one major error that the student made in performing this investigation. 13. Which statement best describes a scientific theory? A. It is a collection of data designed to provide support for a prediction. 11. A biologist in a laboratory reports a new discovery based on experimental results. If the experimental results are valid, biologists in other laboratories should be able to A. repeat the same experiment with a different variable and obtain the same results B. It is an educated guess that can be tested by experimentation. C. It is a scientific fact that no longer requires any evidence to support it. D. It is a general statement that is supported by many scientific observations. B. perform the same experiment and obtain different results C. repeat the same experiment and obtain the same results D. perform the same experiment under different experimental conditions and obtain the same results page 3

4 14. A peppered moth and part of a metric ruler are represented in the diagram below. 15. Base your answer(s) to the following question(s) on the graph and on your knowledge of biology. The graph illustrates a single species of bacteria grown at various ph levels. Which row in the chart below best represents the ratio of body length to wingspan of the peppered moth? The most likely reason there are no colonies in cultures of this species at ph 4 and at ph 10 is that A. (1) B. (2) C. (3) D. (4) A. these bacteria could successfully compete with other species of bacteria at these ph values B. there are more predators feeding on these bacteria at ph 4 and ph 10 than at other ph levels C. at ph 4 and ph 10 the environment is too acidic or too basic for the bacteria to grow D. fertilization cannot occur in these bacteria at ph 4 or ph 10 page 4

5 16. Base your answer(s) to the following question(s) on the information and graph below and on your knowledge of biology. Pulse-rate data were collected from some students during their lunch time for the lab activity, Making Connections. The data are represented in the histogram below. 19. Base your answer to the following question on the information below and on your knowledge of biology. A student performed a laboratory investigation to determine the effect of temperature on the heart rate of Daphnia (water flea). The following temperatures and heart rates were recorded: 20 C 260 beats/min; 10 C 152 beats/min; 25 C 300 beats/min; 5 C 108 beats/min; 15 C 200 beats/min Organize the data by filling in the data table below. Complete both columns in the data table so that the temperature either increases or decreases from the top to the bottom of the table. Temperature ( C) Data Table Heart Rate (beats/min) The histogram includes data from a total of how many students? A. 6 B. 7 C. 10 D Describe one way in which a pulse rate below 45 would disrupt homeostasis in an individual whose average resting pulse rate falls in the range of State one way the data would most likely be different if the pulse rates were collected immediately after exercising instead of during lunch. page 5

6 20. Base your answer(s) to the following question(s) on the information below and on your knowledge of biology. A student performed a laboratory investigation to determine the effect of temperature on the heart rate of Daphnia (water flea). The following temperatures and heart rates were recorded: 22. Plot the data from your data table. Surround each point with a small circle and connect the points. Example: 20 C 260 beats/min; 10 C 152 beats/min; 25 C 300 beats/min; 5 C 108 beats/min; 15 C 200 beats/min Construct a line graph on the grid following the directions below. 23. During which temperature interval did the greatest change in heart rate occur? A C B C C C D C 24. Base your answer(s) to the following question(s) on the provided information and on your knowledge of biology. An insect known as a sawfly is found in evergreen forests in North America. Sawfly cocoons are the main source of food for shrews (small mammals) and some bird species. Scientists studied 1-acre plots in various parts of a state to determine the average number of sawfly cocoons, shrews, and robins. The data collected are shown in the table below. Mark an appropriate scale on the axis labeled Temperature ( C). 21. Mark an appropriate scale on the axis labeled Heart Rate (beats/min). Average Number of Sawfly Cocoons per Acre (in thousands) Data Table Average Number of Shrews per Acre Average Number of Robins per Acre Mark an appropriate scale on each axis. page 6

7 25. Plot the data for shrews. Surround each point with a small circle and connect the points. Example: 27. Base your answer(s) to the following question(s) on the data table and information and on your knowledge of biology. The data table shows water temperatures at various depths in an ocean. Water Temperature at Various Depths Water Depth (meters) Temperature ( C) Using the information in the data table, construct a line graph on the grid following the directions. 26. Plot the data for robins. Surround each point with a small triangle and connect the points. Mark an appropriate scale on the axis labeled Water Depth (m). 28. Plot the data on the grid. Surround each point with a small circle and connect the points. Example: page 7

8 29. State the general relationship between temperature and water depth. 30. The approximate water temperature at a depth of 125 meters would be closest to A. 15 C B. 13 C C. 8 C D. 3 C page 8