Question

Experimental Review

Below are five hypothetical experimental designs. Your job as a reviewer is to pick one of the experiments and write a detailed summary of what is wrong with the proposed study.

Your review should use vocabulary words that have been discussed in class and address the following questions.

Is the study feasible? Will it actually be possible to conduct the proposed study in a controlled manner that produces meaningful data? If there is more than one variable changing simultaneously, no controls, or no replication, then the study is unlikely to produce meaningful data. If there is no way to monitor an experiment in the environment, or no way to conduct the experiment in a controlled environment, like a laboratory, then the experiment is unlikely feasible.

Can you tell from the text if the experiment is designed to be conducted by performing treatments, or by analyzing observational data about a species and its habitat?

Is there a testable hypothesis? Is the study set up so that it will be possible to measure the effects in a quantifiable way? What will be measured? Is there a control group and a treatment group? Or, an independent variable like temperature, and a dependent variable like germination time?

Could you graph the results of this experiment? If so, how would you do it? A column chart to show treatments and controls? A scatter plot or a line graph to look at how changes in the independent variable affect the dependent variable?

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1. Experiments to Review

1. Climate Change Effects on Marine Iguana Mortality

Hypothesis: If the water temperature in the Galapagos Islands changed from being hot (around 77 degrees) to cold (under 70 degrees), then the mortality rate of Marine Iguanas will increase.

Variables: The independent variable is the temperature of the water that the Marine Iguanas live in. The dependent variable is the mortality rate of the Marine Iguanas. The mortality rate of the Marine Iguanas at the average water temperatures of their habitat.

Experimental Treatments: Iguana Group 1 will be water temperatures and marine iguana mortality rates before 1998. Iguana Group 2 will be water temperatures marine iguana mortality rates after 1998

Prediction:By comparting the average water temperatures with the mortality rates every year before the sudden drop in the iguana population and after a trend will be able to be seen. If the water temperature is truly to blame for the mortality rate increase the water temperature will decrease as the population of Iguanas decreases. The control group is intended to show the average number of Iguanas that die due to other causes.

2. Volcanic Ash Impacts Marine Iguana Longevity

Hypothesis: There are several volcanoes between both the Isabela, and Femandina islands which make this the obvious culprit for the extreme rise in mortality in Marine Iguanas.

Variables: The independent variable is the number of volcanic eruptions per year. The dependent variables are the change in pH of the water in the marine iguanas’ habitat, and the mortality rate of the iguanas.

Experimental Treatments: Iguana Group 1 will live on an island with multiple volcanic eruptions each year. Iguana Group 2 will live on an island with no volcanic eruptions.

Prediction: The group of iguanas living on the island with no eruptions will have longer life spans because the pH of the water will not be altered by the large number of volcanic eruptions.