Let's define our biodiversity (Simpson's) index formula:

We are given a list of 5 organisms that Amy found in her backyard:
1st species: Hummingbirds
• 4 individuals
2nd species: Common dandelion
• 33 individuals
3rd species: Yellow winged blackbird
• 8 individuals
4th species: Chipmunk
• 2 individuals
5th species: Hawk
• 1 individual
From our given, we identify that we have 5 species and 48 individuals.
Solving for out BI, we substitute in the numbers to obtain our answer:

Evaluating this, we can approximate the biodiversity index to be around 0.10.