Scientists studied soybean plants grown in sunlit, controlled-environment chambers with a carbon dioxide (CO2) concentration of 700âμmolâCO2/mol of air. The CO2 concentration in the chambers was approximately double that of normal concentrations of environmental CO2. The photosynthetic rate is measured by the amount of CO2 exchange in an area of leaf surface over time. The rate is directly influenced by the activity of the plant enzyme rubisco. During photosynthesis, rubisco fixes atmospheric carbon into an organic molecule as one of the first steps in the Calvin cycle. Scientists measured the amount of carbon fixation that occurred in the leaves of soybean plants grown at each temperature shown in Table 1.

Table 1. Carbon Fixation by Rubisco Under Different Temperatures

Temperature (°C) Carbon Fixation +2SE; (umol/m2/s)
25 91 +9
30 96 +5
35 93 +8
40 104 +7
45 71 +7
50 59 +4

Increased amounts of carbon dioxide in the atmosphere are correlated with increased global surface temperatures. Based on the data, predict how a surface temperature that continues to rise above 40°C most likely affects the amount of energy available to primary consumers in an ecosystem. Provide reasoning to justify your prediction. One model predicts that an increase in greenhouse gases will lead to a 2°C increase in average surface temperature on Earth. Based on the data from the experiment and the prediction of an increase in average surface temperature by the model, predict how the locations of plant species are expected to change over time.