Biology 100/101
Lecture 1:
Introduction to Biology

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Fall 2008

IB 100/101
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Moodle


Scientific Investigation (Corn Borer Experimentation)

From the "Resources" section of the Web resources for Biology: Concepts and Investigations, 1st edition, by Marielle Hoefnagels

Select Chapter 1 -> Labs and Cases -> Virtual Labs -> Dependent and Independent Variables

Start with the "Laboratory Exercise" and look through the "Greenhouse Manual/handbook" to learn about:

  • Corn borers

  • The growth of corn plants

  • BT toxins

  • Transgenic corn containing the gene for BT toxin

The Simulation allows manipulation of:
  • Non-BT Corn Varieties:

    • Golden Crop non-BT

    • Super Harvest non-BT

  • Transgenic BT Corn Varieties:

    • BT 123

    • BT 456

  • Small population of corn borer adults

  • Large population of corn borer adults

  • Two growth chambers

  • Balance to weigh seeds produced by corn plants

Use the simulation to investigate the process of scientific investigation.

    The simulation lets you design and conduct simulated experiments, each of which would take months in the field or greenhouse.

    All possible combinations of the 4 corn seed varieties are available by using the blue "Reset" button at the lower right corner of the screen. Repeatedly click the "reset" button to find the seed varieties you want on the lab shelf.

  • Develop a broad research question based on an independent variable.

  • State your hypothesis (an EXPLANATION).

  • Make a prediction based on your hypothesis.

  • Design, set up, and conduct a virtual experiment.

    • What is your independent variable?

    • What are your control variables?

    • What is/are your dependent variable(s)?

  • Weigh the corn seeds produced in each treatment.

  • Analyze your results.

  • Decide whether you should accept or reject your hypothesis.

Example:

  • Research Question - Are BT 123 transgenic corn plants protected from corn borer populations of high density as well as low density?

  • Hypothesis - The BT toxin produced by transgenic corn plants kills corn borer larvae.

  • Prediction - BT 123 corn will be protected from all corn borer population densities.

  • Design, set up, and conduct a virtual experiment.

    • Independent variable  - corn borer population density - one chamber gets a low density population and the other a high density population.

    • Control variables - BT 123 corn variety is planted in both chambers - plus all growth chamber environmental conditions are the same for both treatments.

    • Dependent variable - the yield measured as the weight of corn seeds produced by the experimental corn plants.

Post your questions and see answers to your classmates' questions in Moodle in the "Talk to Sarah and Ed" forum.