[Campbell Biology P.726] A new research study uncovers extensive evidence suggesting a signi... | Practice Question

A new research study uncovers extensive evidence suggesting a significant global increase in atmospheric oxygen levels immediately preceding the Cambrian explosion. Based on the provided text, how would this finding most likely contribute to our understanding of the Cambrian explosion?

  • A: It would strengthen the hypothesis that predator-prey relationships were the primary driver of diversification.
  • B: It would provide strong support for the hypothesis that increased atmospheric oxygen enabled higher metabolic rates and larger body sizes, facilitating animal diversification.
  • C: It would primarily confirm that genetic changes, such as the origin of Hox genes, were the sole cause of the new body forms.
  • D: It would primarily explain the decline of animal diversity in the Ordovician, Silurian, and Devonian periods.

Explanation

The text states: 'Another hypothesis focuses on an increase in atmospheric oxygen that preceded the Cambrian explosion. More plentiful oxygen would have enabled animals with higher metabolic rates and larger body sizes to thrive, while potentially harming other species.' Therefore, evidence of increased oxygen directly supports this hypothesis as a driver of Cambrian diversification.