During a drought on the Galapagos islands, finches with larger beaks were able to crack the large tough seeds produced by plants that survived the dry conditions. This is an example of ____.
A. genetic drift
B. a founder effect
C. stabilizing selection
D. directional selection
E. disruptive selection
D. directional selection
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As activity level and metabolic rate increase, ____ is generated as a consequence of the second law of thermodynamics
Fill in the blank with the appropriate word.
Trophic pyramids typically have a ____ base and a ____ top portion
a. narrow; narrow b. narrow; wide c. wide; narrow d. wide; wide e. flat; flat
What ecological role were the nitrogen-fixing Bradyrhizobium japonicum bacteria in soybean root nodules effectively playing when the experimenters cut off gaseous nitrogen?
a. parasite c. commensal b. predator d. symbiont
Which of the following does not provide evidence supporting the hypothesis that charophytes are the closest living relatives of land plants?
a. Both charophytes and plants have multicellular individuals. b. Charophytes and plants produce cellulose in similar ways. c. Charophytes and plants have structurally similar sperm. d. Nuclear DNA sequences of charophytes are more similar to those of plants than are those of other algae. e. Mitochondrial DNA sequences of charophytes are more similar to those of plants than are those of other algae.