Overview
Like any research institution, The Peggy Notebaert Nature Museum studies
natural populations, including butterflies. The specimens and data we
collect are used to form a record over time and monitor any changes. We
use both physical collections and field studies to research butterflies
in the Chicago Area.
Our
Insect Collections
One way we study butterflies
is through our collections. The Peggy Notebaert Nature Museum maintains
a collection of everything from plants and animals to fossils and minerals.
These specimens form a record for scientists to study. Most of our collection
was acquired between 1850 and 1950, and the vast majority of specimens
are from the North American Continent. These collections provide baseline
data for studies of our environment as well as a document of how humans have
changed ecosystems over time. A collection gives scientists a window
into the past, helping them better understand changes occurring today,
and aiding in planning for the future.
Of
the 200,000 or so specimens here at the Academy, approximately 50,000
specimens are insects. Most of these were collected in the Chicago area
before 1900 and belong to the orders Lepidoptera (butterflies and moths)
and Coleoptera (beetles).
The Lepidoptera have recently been reorganized, revealing specimens collected by such notable
collectors as Berthold Neubarth, Leslie Banks and Harry Sicher.
The insects themselves, and the accompanying information about when,
where, and by whom they were collected, can paint a vivid picture of
what butterfly populations were like in the past.
Field
Studies
Data is also collected about populations using field studies. Data
collectors visit sites in the Chicago area and collect specific information
about the butterflies they observe there. As you can see in the sample
below, the habitat type is recorded as are the weather conditions for
the site. Then the number of each species are counted using transects,
or lines through each site. Transects are a method of sampling, or studying
a representative portion, when the total area to be studied is too big.
Other information collected for each site include Hi Count (the highest
number of a given species seen in an hour), total number of species
seen in a given year, and the total number of different species seen
at that site to date.
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Why
Collect Data?
Scientists
collect data for several purposes including: to measure change in a region
or species over time, to identify possible causes of changes seen in the
wild, and to provide a historic record of an area. By documenting the
species living in an area, scientists can learn more about species interactions
in a region. Would you like to help and collect
some of your own data?.
Data,
Data Everywhere--Let's Think
By
now you've learned about all the kinds of data we collect at the museum
on butterflies and are wondering what happens next. There is an awful
lot of information sitting in notebooks, but information is only information
until scientists study it to find out what meaningful things it has to
say. Like a detective trying to piece together the evidence at the scene
of a crime to figure out who did it, scientists sift through the large
piles of data they collect to determine answers to their questions. Questions
that might be answered by the data we have include:
- Did
the number of any type, or species, of butterfly change during the
timeframe of the study?
- Did
any "new" species of butterfly suddenly appear or "original" species
disappear during the timeframe of this study?
- Were
the different kinds of butterflies more abundant (more of them) at
some sites than others?
- Were
certain conditions present (i.e. habitat type, weather conditions,
temperature) that seem to be linked to the presence of certain species
of butterfly in the counts?
Can you think
of other questions the data collected might be able to answer? If their
was a change in the population of a species, what might cause such a change?
Write out some hypothesis and determine what information you would need
to test them. Could the data we already have determine the answer? Perhaps
or perhaps not.
Analyzing
Data
Asking questions is easy, finding out the answers
can be hard. Fun, but hard. How would you go about answering the first
question in the list, " Did the number of any type, or species, of butterfly
change during your study?" Scientists try to answer their questions in
two major ways: mathematically and graphically.
Mathematic analysis works with actual numbers and performs tests on them.
These tests can involve adding, subtracting, multiplying, or dividing numbers
and comparing them to each other. Mathematical analysis is often referred to as statistics.
Graphical representations are visual representations of the mathematical
analysis. They are pictures, or graphs, with lines or bars to illustrate
the data. If changes do occur, the graph will show them. Often scientists
use the two techniques together.
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