IB ESS Unit 2: Ecosystems & Ecology (id: bc7773ef3)

本题目来源于试卷: IB ESS Unit 2: Ecosystems & Ecology，类别为 IB环境系统与社会

[单选题]
Figure: Species data for species sy- nx2rcalw1( ampled in two parts of Willohd2dxhp* 5i x-w Creek




Willow Creek runs north to south past Happy City. Ecologists want to investigate the effect the city is having on the diversity of the Willow Creek ecosystem.
Calculate Simpson’s Diversity Index for the locations north and south of the city to determine the effect of the city on the creek.

A. Happy City is having a positive impact on creek diversity.
B. Happy City is having a small negative impact on creek diversity.
C. Happy City is having a large negative impact on creek diversity.
D. Happy City is having no impact on creek diversity.


参考答案:  D


本题详细解析:
$D_{North}$= $\frac{302(301)}{26(25)+33(32)+7(6)+55(54)+90(89)+3(2)+76(75)+2(1)+10(9)}$

$D_{North}$= $\frac{90902}{18256}$

$D_{North}$= 4.979

$D_{North}$= 5.0

Similarly,$D_{South}$

= 6.0

The higher the number the greater the diversity, so since the creek runs north to south the city appears to be having a positive effect on the biodiversity in the creek.

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