SAT Subject Biology Practice Question 437: Answer and Explanation
7. Which of the following represents the proper ecological hierarchy?
A. Population → community → ecosystem → biosphere
B. Ecosystem → community → population → biosphere
C. Population → ecosystem → community → biosphere
D. Biosphere → ecosystem → population → community
E. Community → population → biosphere → ecosystem
Correct Answer: A
A The biosphere is the highest level of organization, so choices D and E can be eliminated. Populations represent a lower level of organization than ecosystems, so choice B can also be eliminated. Finally, a community is the next step up from populations, choice A is correct and C is wrong.