bio 121 Lab exam

How many pairs of legs does a pillbug have?

7

A good scientific experiment is reproducible. What does this mean? a.

Anyone can conduct the same experiment in another lab and expect the same results.

stage clip

Holds the slide in place

In an experiment, the researcher usually has only one ______________ variable, but collects/records multiple ________________ variables.

Independent; dependent

What is the purpose of a control group in scientific experiments?

The control group undergoes no treatment and serves as a baseline comparison to the group receiving an experimental treatment.

Why do scientists put so much effort into documenting their experiment and analysis?

because other researchers must be able to repeat the experiment in order to check the results

field of view

circular area seen through the eyepiece

ocular

contains a lens at the top of the body tube

In the pillbug experiment where you tested dry substances, the substance used as the CONTROL was ________.

cornstarch

nosepiece

rotating part to which the objective lenses are attached

arm

serves as a handle for carrying the microscope

When preparing your experiment for a laboratory exercise, the factors that remain the same between the experimental group and the control group are called ______.

standardized variables

What do scientists call the information they collect while doing experiments or making observations?

theories

while looking at a specimen under a compound light microscope, using the stage control knob, you move the slide to the rt. which way does the image move

to the left

You decide to test your pillbug's preference for an acidic environment versus a nonacidic environment. On one of the chamber you place water. What is an appropriate test substance to place in the other chamber?

vinegar (pH 2)

Which best describes the pillbug's organ of respiration (i.e. what organ do they used to breathe)?

gills

in the pillbug experiment, IF the pillbugs in the experimental side of the choice chamber (your dry substance), would have moved to the side of the chamber with sand instead of your dry substance, what would you have concluded?

Pillbugs tend to prefer sand over the other dry substance.

When pillbugs are placed in a choice chamber, which one of the following behaviors indicates a preference for the the test substance?

pillbug spends more time in chamber with test substance

If you wanted to test whether or not a particular pain reliever was effective in the general human population, you would need to design and an experiment with an experimental group and a control group. What should be the ONLY difference between thee two groups?

The treatment the groups receive: the experimental group receives the pain reliever and the control group receives a placebo.

How does a pillbug usually react when confronted with an unwanted substance?

moves away from it

The correct flow of the scientific method is

observation, formulate hypothesis, perform experiment, data analysis, conclusions

viewing the dissecting microscope, the blue tape is indicating?

occular lens eyepiece

This behavior helps a pillbug avoid dangerous situations.

Rolls up into a ball

Some students consume large amount of caffeinated drinks to help them stay alert when studying. You notice that many who engage in this practice seem to do poorly on exams. Suppose you want to investigate the relationship between caffeine consumption and exam performance. Which of the following statements would be an appropriate hypothesis?

Students who consume large amounts of caffeine while studying have lower exam scores than students that consume less caffeine while studying.

What is a hypothesis?

a tentative explanation to your question or observations

You are testing the difference between a meat-based diet and a vegetable diet on tadpoles in a laboratory. You want to see if the meat-based diet will increase the average weight of the tadpoles. Such factors as the tadpole species, temperature of water, pH of water and the amount of food are the same for each group. What is the INDEPENDENT variable for this tadpole experiment?

diet/food type

If the hypothesis in a scientific experiment is NOT supported, the experiment is considered a complete failure and must be repeated until a satisfactory outcome is reached.

False