MB Chapter 10 #36

Part D Assuming that the y-axis tick marks will be separated by 10 (0, 10, 20, and so on), what is the largest value that should appear on the y-axis?

100

Part C Assuming that the x-axis tick marks will be separated by 200 (0, 200, 400, and so on), what is the largest value that should appear on the x-axis?

1200

Part G Select Figure 2 from the drop-down menu above the data table to see the final graph (Figure 1). What is the relationship between increasing concentration of CO2 and the dry mass of corn?

As CO2 increases, the dry weight of corn decreases.

What is the relationship between increasing concentration of CO2 and the dry mass of velvetleaf? What is the relationship between increasing concentration of CO2 and the dry mass of velvetleaf?

As CO2 increases, the dry weight of velvetleaf increases.

Considering that velvetleaf is a weed invasive to cornfields, how would you predict increased CO2 concentration to affect interactions between the two species?

As atmospheric CO2 rises, velvetleaf weeds may grow larger and better compete with corn, reducing grain yields.

Part B What variable's response to the independent variable was measured by the researchers, and what are the units for this variable?

Average dry mass of one plant, in grams

Part A - Making a graph with the data To explore the relationship between the two variables, it is useful to graph the data in a scatter plot, and then draw a regression line. But first, you must determine which variable should go on each axis of the graph. What variable did the researchers intentionally vary in the experiment, and what are the units for this variable? (This is the independent variable.)

Concentration of CO2 in the air, in parts per million

If atmospheric CO2 concentration increases from 390 ppm to 800 ppm, what is the estimated percentage change in dry mass for corn? For velvetleaf?

Decrease by 8, Increase by 32

Part M - Evaluating a hypothesis Do these results support the conclusion

Yes, because C3 velvetleaf had a positive growth response to increased CO2, but C4 corn had a negative growth response to it.

Part K What is the estimated dry mass of corn and velvetleaf plants at an atmospheric CO2 concentration of 800 ppm?

c 84 v 50

What is the estimated dry mass of corn and velvetleaf plants at an atmospheric CO2 concentration of 390 ppm (current levels)?

corn: 91 g; velvetleaf: 38 g