Biodiversity Lab
Why is biodiversity important anyway???
When a habitat is very diverse with a variety of different species, it is much
healthier and more stable!!! One of the reasons for this is that disease doesn’t
spread as easily in a diverse community. Consider the potato blight and the
subsequent famine that ravaged Ireland in the 1800’s… A third of Ireland’s
population was completely dependent on that ONE crop (a monoculture) so it
only took ONE disease to wipe out a large portion of the population’s food
source. Mass starvation, disease among people, and emigration followed…
More biodiversity = More stability = Healthier ecosystem!!!
The lab…
You will be quantifying (calculating) the biodiversity of a community using the
Shannon-Wiener diversity index. The index ranges from about 0 -7; 0 for a
community with a single species (no biodiversity), to over 7 for very diverse
communities.
The formula for biodiversity is:
H = -sum[pi x (ln pi)]
Where pi = ni
N
(number of individuals in one species)
(total number of individuals overall)
You will also quantify the richness and evenness of a community. Richness is
simply the number of species represented in a community. (For planet Earth, it
declines along equatorial gradient). Evenness is a measure of how similar the
abundance of different species are (for example: if there are 50 trees in a
community and 49 are Oak while only one is Elm, the two species represented
are NOT even. If there are 25 Oak and 25 Elm, the two species represented are
perfectly even). Evenness will range from 0 to about 1; 0 being completely
uneven, to 1 for being completely even. (It may work out to slightly over one for a
community whose species abundance is completely even).
The formula for richness is:
The formula for evenness is:
The lab write up…
Title
Purpose
S (count up the number of species represented
and that equals richness)
E = H/lnS
Background: A paragraph at least (use the internet or your book – chapter 12
talks about reasons for biodiversity decline worldwide)
Hypothesis: If we measure the biodiversity of the faculty parking lot and the
student parking lot, then…
Materials
Procedure: Number form
Results: YOUR OWN data chart (NOT the messy one you used outside)
Analysis: Calculations, clearly state your answers and label; Graph – don’t forget
to label your graph!!! And, will you use a bar graph or a line graph? A bar graph
makes a comparison or shows measurements, a line graph shows a trend over
time.
Conclusion: What are you measuring? Do your results support or reject your
hypothesis? (Do NOT use the words “proved correct or incorrect”) What are
some possible sources of error?
Post lab questions!! (Answer in complete sentences)
1. Would you expect the diversity index to be high or low for a shopping mall
parking lot? (EXPLAIN why or why not)
2. Would you expect the diversity index to be high or low for a new car
dealership lot? (EXPLAIN)
3. Would you expect the diversity index to be high or low for a desert
ecosystem? (EXPLAIN)
4. Would you expect the diversity index to be high or low for a tropical
rainforest? (EXPLAIN)
5. Would you expect the diversity index to be high or low for a Christmas tree
farm? (EXPLAIN)
6. Growing only one type of plant is called a monoculture. Give an example
of a monoculture and where would a monoculture fall on the ShannonWiener index? (Don’t use the potato crop in Ireland).