Biology 3370
Ecology Final Lab Report
Spring 2008
Your final lab assignment is to use the pine data we collected from the hillsides
behind the Science Building to test hypotheses related to the factors influencing
pine distribution and abundance. The final product for this assignment is a formal
lab report. Your lab report is due no later than Monday, April 28 during lecture.
To help you think about and organize your lab report, I have listed a number of
hypotheses based on the class readings and discussions. I have also generated a
number of testable predictions associated with those hypotheses. You must select
at least one of the hypotheses as the basis for your lab report, then decide which
combination of predictions will allow you to test that hypothesis. If you feel you
need to select more than one hypothesis to adequately explain pine distribution and
abundance, you may do so. Regardless of the hypothesis(es) you choose, you must
make a reasonable, logical argument for why the predictions you selected will test
that hypothesis.
The structure of your lab report should follow the formatting rules we use for
standard lab reports in the biological sciences. If you are unsure what this means,
this link will take you to the lab report guidelines we provide in Biology 2101. The
first part of the document is a simple example of a lab report. The second portion
lists expectations for each section of the lab report. There are some minor
modifications that you should be aware of.
Introduction
The sample introduction does not include any literature citations. Your introduction
must include reference to the articles you read and disussed in lab. This is
essential information you will need to develop a logical introduction to support the
hypothesis(es) and predictions you hope to test.
Methods
You do not need to include information on the data collection techniques we used in
the field. You do need to explicitly state the dependent and independent varaibles
you will be using in your predictions and an explanation of how you will use
inferential statistics to test those predictions.
Results
Only include the summary data (either in tabular or figure format) you need to test
your predictions. We collected a LOT of data and I do not need to see it all. I only
want to see the information YOU used. Your results narrative should fully
summarize the information you need to support your inferences.
Discussion
All rules apply…
Literature Cited Section
You must include a literature cited section that lists all of the studies you
referenced either in your Introduction or Discussion section. Standard citation
format is required.
Listed below are the potential hypotheses and predictions you should be able to
test with our data sets.
Possible Hypotheses
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Moisture affects pine germination.
Light affects pine germination.
Moisture affects pine growth.
Light affects pine growth.
Seed dispersal affects pine distributions.
Density affects pine growth.
Possible Predictions
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There are differences in moisture levels at the various locations on the
hillside.
There are differences in light intensity levels at the various locations on the
hillside.
Areas with differing pine densities will show differences in growth.
There will be more seeds deposited closer to the parent stand, therefore
there will be a higher density of young trees near the parent stand.
Seedling germination will be higher where there is higher light intensity.
Seedling establishment and growth will be higher where there is higher light
intensity.
Seedling germination will be higher where there is higher soil moisture.
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Seedling establishment and growth will be higher where there is higher soil
moisture.
Structure of Data Sets
To eliminate confusion concerning quadrat locations, I have renumbered the
quadrats collected by the Wednesday lab section. For sites 1, 2 and 3, Wednesday
quadrats 1, 2 and 3 have been renumbered as quadrats 4, 5 and 6, respectively. In
all of the sites (1, 2, and 3) and areas (Upper – U, Middle – M and Lower – L),
quadrats 1 and 4 were located in the left side of the area, quadrats, 2 and 5 were
located in the center of the area and quadrats 3 and 6 were located on the right
side as your are facing up the hillside.
As we were out on the hillside, I suggested that height could be used as a
surrogate of age for our pines. After examining the pine height data collected by
both classes, it was possible to distinguish two separate, and perhaps meaningful
age groups. The first was a group of pines that were less than 30 cm in height. In
all likelihood, these were trees that germinated during the spring of 2006 or 2007,
so they are in their first or second year of growth. I have labeled these pines as
Age Class 1 in the Excel spreadsheet. The second group are pines that germinated
sometime between the spring of 2001 and 2005. I have labeled these as Age Class
2 in the spreadsheet.
Finally, the days we sampled were not the best to get a true estimate of light
intensity levels on days of full sun. Although we can use our data to test some of
the predictions, I have also included light intensity data collected by the Spring
2007 Ecology class to supplement your data sets.
Listed below are the data tables available in the Excel file.
Table 1. Raw data collected by the Monday and Wednesday classes. Site, section
and quadrat are as indicated in the assignment handout. All height
measurements are in centimeters.
Table 2. Number of Age 1, Age 2+ and total number of pines (excluding 11+ age
class) pines found in each quadrat sampled by Monday and Wednesday's lab
sections. Site numbers, sections and quadrat numbers are as given in
assignment handout.
Table 3. Light intensity data collected by the Monday and Wednesday Lab
sections. Site, section and quadrat are as indicated in the assignment
handout. Light measurements are in lux.
Table 4. Soil moisture data collected by the Monday and Wednesday lab sections.
Site and location are as indicated in the assignment handout. The %
moisture was obtained by weighing the samples, drying them to constant
weight at 100 C and then reweighing them. The difference between original
and final weights represent the peercent moisture.
Table 5. Number and circumference (cm) of older pine trees (ages 11+ and older)
from sites 3 and 4. Data were collected by the Wednesday lab section.
Table 6. Light intensity data collected from the north and west facing slopes of
the hillside by the Spring 2007 Ecology class. All measurements were taken
between April 3 and April 17 on sunny days. Data were obtained at 9:00 am
(morning), 12:30 pm (noon), and 4:00 pm on each day from four points on
each hillside. Points 1 and 2 are on the upper portion of the slopes, points 3
and 4 are on the lower portion of the slopes. Averages and standard
deviations are based on 4 observations at each point.