BIOL 1005 Lecture : Biology 1005 Notes

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azuremammoth471

15 Mar 2019

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Formulating hypotheses: before we design an experiment to test a model we need to formulate a null and an alternative hypothesis, the null and alternative hypotheses. Prediction: hypothesis will only state whether we will or will not see a difference between 2 groups, a prediction. Experiment: interested in testing whether fertilizer will have an effect on the number of fruits produced by a tomato. Null: there will be no difference in the number of fruits produced by the plant grown with the fertilizer compared to the plant grown without fertilizer. Alternative: there will be a difference in the number of fruits produced by the plan grown with the fertilizer compared to the plant grown without it. Some important considerations: number of variables to be manipulated, one!!! (for our purposes, because multivariate requires more complicated analyses and experimental designs, the group in which the variable is manipulated is called the experimental.

Related Questions

The investigator never begins an experiment without a prediction of its outcome. The prediction is always based on the particular experiment designed to test a specific hypothesis. Predictions are written in the form of if/then statements: "lf the hypothesis is true, then the results of the experiment will beâ¦"; for example, "if cactus spines reduce herbivory, then removal of the spines will result in greater surface area removed by herbivores." Making a prediction provides a critical analysis of the experimental design. If the predictions are not clear, the procedure can be modified before beginning the experiment. For the soybean experiment, the hypothesis was: "Exposure to sulfur dioxide reduces reproduction." What should the prediction be? State your prediction.

To evaluate the results of the experiment, the investigator always returns to the prediction. If the results match the prediction, then the hypothesis is supported. If the results do not match the prediction, then the hypothesis is falsified. Either way, the scientist has increased knowledge of the process being studied. Many times the falsification of a hypothesis can provide more information than confirmation does, since the ideas and data must be critically evaluated in light of new information. In the soybean experiment, the scientist may learn that the prediction is true (sulfur dioxide does reduce reproduction at the concentration tested). As a next step, the scientist may now wish to identify the particular level at which the effect is first demonstrated. Review your hypotheses for the numbered questions. Consider how you might design an experiment to test the first hypothesis. For example, you might measure auditory function by performing hearing tests or observing changes in structures in the ear. The prediction might be:

IF cell phone usage reduces auditory function (a restatement of the hypothesis),

then people who use cell phones will score lower on hearing tests than persons who do not (predicting the results from the experiment).

Now consider an experiment you might design to test the second hypothesis. How will you measure "mental advantage"?

State a prediction for this hypothesis and experiment. Use the if/then format:

The actual test of the prediction is one of the great moments in research. No matter the results, the scientist is not just following a procedure but truly testing a creative explanation derived from an interesting question.â

1. Honeybees provide 80% of the pollination services for crops, including almonds, squash, melons, alfalfa, apples, and pumpkins. Migratory beekeepers transport over 2 million hives to farmland as crops begin to flower. In 2006-2007 beekeepers were alarmed when 50% of the honeybee colonies in 26 states were lost. In fact one of the biggest mysteries was that the bees were not found dead in the hives, but rather were simply gone! Scientists have termed this Colony Collapse Disorder (CCD). They are currently considering three alternative hypotheses: emerging pathogens (viruses, bacteria, and/or fungi), environmental toxins or chemicals; or abduction by humans (or aliens). Using the criteria in Lab Study B, Developing Hypotheses, select the hypothesis you would pursue as a scientist and justify your choice.

Instructions:

Read the scientific inquiry below. Use the data and your scientific knowledge, to complete the questions in each of the sections on the rest of this document. Place your answers, in the space provided and bold or change the color of the text of your answer. Once the assignment is complete, save it as a PDF document file. To submit this assignment, email the completed PDF document to your instructors email address by the due date/time. This assignment is to be done individually. Per the Angelina College student handbook, plagiarism will be will not be tolerated.

Scientific Inquiry:

A farmer wishes to determine which of the two fertilizers, Brand X or Brand Y, helps his corn crops grow at a faster rate in a five-week period of time. He asks his daughter, whom is a college freshman taking introductory biology, to design an experiment to help him test each fertilizer. They decide to grow three different crops of corn, each grown in a controlled environment, receiving the same amount of sunlight, same climate, soil type, and water. Crop 1 will receive no fertilizer during watering. Crop 2 will receive Brand X fertilizer while watering. Crop 3 will receive Brand Y fertilizer while watering. The farmer and his daughter performed the experiment and collect data on each fertilizer over a five-week period. Use the data, represented in Table 1, to complete the following assignment.

Table 1. Average height of corn plants when treated with Brand X or Brand Y fertilizer compared to corn plants not treated with fertilizer (control).

Time (T) in weeks	Control (cm)	Brand X (cm)	Brand Y (cm)
0	0	0	0
1	1.3	1.4	1.2
2	2.4	2.7	2.3
3	4.2	8.3	7.3
4	6.8	12.4	8.2
5	8.7	16.8	11.6

Section 1: Representation

Define each term or variable, with respect to the scientific inquiry.

Independent variable-

Dependent variable-

Control group-

Experimental group(s)-

Hypothesis-

Write the equation to determine the average growth rate, with the appropriate values included, for each corn crop type (control, Brand X, and Brand Y). Use the equation shown below.

Growth rate = (T₅ â T₀)/5

Control =

Brand X =

Brand Y =

Section 2: Calculation

Solve the equations generated, in question 2, for each corn crop type. You must show your work, in the space below, for full credit.

Control =

Brand X =

Brand Y =

Section 3: Interpretation

Analyzing the data table and the calculated growth rates, complete the following questions.

Which crop type grew the fastest? Explain your answer using factual information.

Which plant was tallest? Explain your answer using factual information.

What can you conclude about the treatment of fertilizer on crop growth? Explain your answer using factual information.

Section 4: Application and Analysis

What could happen if the temperature were not controlled during the experiment? Would this impact treatment effectiveness on plant growth? Explain your answer.

Do you think the same outcome would occur if pine trees were used? Explain your answer.

If a particular fertilizer works on corn crops, should we be using that fertilizer on all plants? Why or why not?

sangriacrab554

SECTION II. SHORT PARAGRAPH QUESTIONS (25m) Answer each of the following four questions in full sentences. Do not use point form. (9m) The great majority of land plants establish mycorrhizal associations with fungi, in which there is a two-way exchange of nutrients between the plant and the mycorrhizal fungus. Host plants provide mycorrhizal fungi with sugars, while mycorrhizal fungi provide host plants with soil phosphorus. a. Design an experiment to test whether Douglas-fir seedlings grow more quickly in soil containing mycorrhizal fungal spores. Make sure that you state your null and alternate hypotheses, list your dependent and independent variables, describe your experimental setup (including control and experimental treatments), list your controlled variables (explaining how each will be controlled and why), and provide replication. b. Assuming that the results of the experiment support your alternate hypothesis, draw a graph to predict what the resulting data would look like. Donât forget to label your axes!

BIOL 1005 Lecture : Biology 1005 Notes

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