DiversityG.3.1 – G.3.5 IB Standards
AP Learning Objective- 4.27= The student is able to make scientific claims and predictions about how
species diversity within an ecosystem influences ecosystem stability
Simpson Index Equation (N = total number of individuals; n- number of individuals per species, D=
Diversity Index (IB – know equation for IB test AP- given on equation sheet)
D = N(N-1) / Summation(n*(n-1))
Example :
species
(n)
(n-1)
(n)*(n-1)
Daisy
Buttercup
Dandelion
clover
N
345
260
342
598
1545
344
259
341
597
118680
67340
116622
357006
=659648
D= 1545(1545-1)/(345(345-1)+260(260-1) + 342(342-1) + 598(598-1))= 3.62
1. Calculate Simpson Diversity index for two communities (Madagascar & Mojave) see handouts
2. Analyze the difference use bar graph
3. Recalculate Simpson Diversity when ravens (an invasive species) move to the desert following
urbanization. The estimated number of ravens is 1500. They eat baby tortoises and the population
decreases by 75%. Since California desert tortoises are a keystone species, what is effect of these
invasive species on the entire ecosystem?
4. Discuss the impacts of alien species on ecosystem? List 3 examples of the introduction of alien
species that had significant impacts on ecosystems.
5. Discuss reasons for conservation of biodiversity using rainforests as an example.