[Campbell Biology P.590] Based on Figure 25.20, "Fossil extinctions and temperature," and it... | Practice Question

Based on Figure 25.20, "Fossil extinctions and temperature," and its accompanying text, which of the following conclusions can be drawn?

  • A: Periods of high global temperatures are consistently associated with increased extinction rates.
  • B: All mass extinction events exclusively occurred during periods of warmer relative temperatures.
  • C: The figure specifically quantifies the exact temperature values for each extinction event.
  • D: The current extinction crisis has already reached extinction rates comparable to the 'Mass extinctions' shown in the figure.
  • E: Relative temperature 0 on the x-axis represents the average global temperature over the last 500 million years.

Explanation

The text for Figure 25.20 states, "Extinction rates increased when global temperatures were high. Temperatures were estimated using ratios of oxygen isotopes and converted to an index in which 0 is the overall average temperature." This directly supports options A and E. Option B is incorrect as seen from the scatter plot, where some mass extinction points are in the 'Cooler' range. Option C is incorrect as the x-axis represents a relative index, not exact values. Option D is explicitly contradicted by the text about the "big five" extinctions.