APES Biodiversity
Fun with Biodiversity….
What does it mean? What does it depend on? Can we
measure it?
Bugs! On earth they outnumber us. It isn’t even close! The diversity of insects on
our planet exploded when flowering plants evolved. Why do you think this happened? How could
the presence of different kinds of plants have influenced insect diversity?
The main objective of this activity is to think about biodiversity and work with it; specifically we
will see how plant diversity affects insect diversity. Plastic yellow bowls will be filled with water
and salt. Yellow is attractive to many types of insects and other arthropods and they will be drawn
to the bowls. The water will trap the insects in the bowls while the salt will keep the arthropods
from absorbing too much water. (Why is this? Think biology…think osmosis.)
Objectives:
1) To think about and work with the concept of biodiversity in a field study.
2) To study the impact of school habitats on arthropod richness (i.e., number of species) and
abundance (i.e., total number of individuals).
3) To attempt to group arthropods according to morphological characteristics and generally
think about classification schemes used in biology…why and how?
4) To review the use of a stereoscope microscope
5) To review the use of Excel.
Observation:
If you’ve ever walked around our school grounds, they don’t appear to be incredibly rich in
species. The plant community is fragmented and represented by a limited number of species that
were planted by our maintenance staff. Nature has planted a few organisms here and there that
haven’t been removed. The plant community directly affects arthropod richness and abundance.
The courtyard was planned and planted by students with help from a professional landscaper in
2008-2009. It has some interesting diversity including native and non-native species; we’ll work
there, mostly.
Problem: Let’s look for arthropods and see if their abundance and diversity are related to plant
diversity and abundance.
Methods:
Day One: Student researchers will receive one yellow plastic bowl and a one meter long piece of
string. The bowl should be filled with one cup of water and 2 teaspoons of salt. A few drops of dish
detergent should be added (why?). Researchers may place their bowl in the courtyard or anywhere
around the school grounds as determined by the class. A rock should be placed in the bottom of the
bowl so it doesn’t blow away. In pairs, the researchers measure how many plants and plant species
are within 3.14 m² (where did this number come from?) of the bowl. One partner will hold one end
of the string at the bowl and their research colleague will hold the other end. Holding the string
taunt, one researcher will walk in a circle around the bowl and count the number of individual
plants and plant species the string passes over. This data should be recorded in the spaces
provided below. The bowl should be left in place for 24 hours. The bowl color can be changed to
add a variable into the experiment.
Day Two: After 24 hours, the researchers pour the contents of the yellow bowl into a beaker and
bring it indoors for analysis.
INDOORS: Pour a small amount of sample into a Petri dish. Using a stereoscope microscope, study
the specimen you have collected. Group the arthropods into major groups based on morphology;
i.e. insects with two wings are flies (Order Diptera), insects with four wings may be bees (Order
Hymenoptera), insects with no wings may be springtails (Order Collembola) or ants (Order
Hymenoptera), and non-insects may be spiders (Order Araneae) or harvestmen (Order Opiliones).
Count the number of arthropods in each major group and record the number of arthropod species
and total number of arthropods. If you are interested in identifying your insects, see the teacher
for help (you can use field guides and the internet).
Enter your class data into Excel and the class will create a figure showing the richness and
abundance of arthropods versus plant abundance.
Calculate the biodiversity index for your sample. _________________________________
Discussion: What do the data say about arthropod specie richness and abundance as related to
plant species and abundance on our school grounds? Which arthropod orders are most attracted to
yellow bowls in school environments? What types of biodiversity indecies did students obtain?
Comment on the biodiversity of our school grounds.
Data and Observations
Day One
Describe the location of your bowl.
How many different kinds of plants are
there?
Give some names if you can identify any
of them.
Day Two
How many insects did you collect?
What Orders were represented? How many in each order?
Sketch an insect you collected on separate paper.
adapted from Matthew L. Richardson, UIUC,2006
drawings from: www.entomology.cornell.edu/Extension/DiagnosticLab
How many total plants are there?