Biology 1114 Beetle Project

Name___________________

Biology 1114 Research Project Worksheet

Answer all questions, written in bold (10 points). This worksheet is designed to help you organize your thoughts about this experiment and to facilitate writing your report.

-How are your beetles classified (to which class, order and family do they belong)?

-How many adult beetles will be placed in each jar?

-Write here what the amounts of food in each jar will be:

-How much vermiculite will be in each jar?

-What are we trying to find out?

Predictions- Make predictions on how your beetle populations will react to changing food and space conditions.

Experimental Methods- What is the difference between a control and experimental group?

Which jar is the control jar and which are the experimental ones?

Independent and dependent variables:

The independent variable is the factor being manipulated or changed by the researcher.

The dependent variable is the product of changing the independent variable, these are your results.

Let’s try an example. Imagine you feed two groups of white flamingoes with different diets. One group feeds on fish, the other group feeds on shrimp. You hypothesize the group feeding on shrimp will turn a pink color.

What are the independent and dependent variables in the shrimp and flamingo example?

Now name the independent and dependent variables in the beetle exercise.

Control Variables. When doing an experiment, we want to make sure we are testing only the variables we manipulate. So, we have to keep other living conditions uniform. These are called control variables and they should not change throughout the experiment. For example, in an experiment of coral growth, we would want to keep the water temperature and amount of light the same throughout the course of the experiment.

Name some control variables (variables that should not change) in our jars:

Determine the null and alternative hypotheses. The null hypothesis is the one we test, the alternative hypothesis contradicts the null hypothesis, it is probably the one we favor. We accept or reject the null hypothesis based on the outcomes of the experiment. In actual practice, it is difficult to prove the null hypothesis is true, so if we reject it, then our alternative hypothesis gains credibility.

Let’s try an example. You are testing the number of times that young lobsters leave their hiding places and search for food each hour during the evening. You feel that lobsters in dark tanks will make more searches per hour than lobsters in well lighted tanks.

Your null hypothesis will be, “there are no differences in the number of searches by young lobsters in tanks that are either dark or well lighted.” Your alternative hypothesis will be, “there are differences in the number of searches by young lobsters in tanks that either dark or well lighted.”

Write your null and alternative hypotheses for the beetle experiment. Since we have two experimental jars, we have two sets of hypotheses:

1. Null Hypothesis

Alternative Hypothesis

2. Null Hypothesis

Alternate Hypothesis

Sources of error. When doing an experiment, you try to take special care to not introduce error, but some may still occur. Can you think of possible errors in this experiment?

Possible errors: