Week 1:
Winter Ecology and the Scientific Method
Before Lab: Every week be sure to read over the entire lab before you get to
class. Most weeks there will be a short pre-lab quiz.
What to Bring to Lab: Make sure to bring this lab print-out as well as a
notebook to write down observations out in the field.
Also, be sure you are wearing warm clothes and shoes you don’t
mind getting wet since we’ll be walking around in the woods for up to
an hour. This is snow, rain or shine. Consider yourselves warned.
Background:
Introduction: Asking “Why?” is arguably one of the central characteristics of
human behavior. We have a natural curiosity about the world around
us. Indeed, our knowledge and understanding of the world around us
has progressed increasingly rapidly over the last 200 years. How is it that
so much has been learned in such a relatively short period of time?
Scientists have formalized a process that enables them to solve
problems and gain knowledge in a consistent and repeatable fashion.
Because science is inherently a public activity, this consistency and
repeatability are vital and allow others (scientists and non-scientists
alike) to evaluate the results. All good science has a similar structure,
referred to as the Scientific Method . Although scientists and textbooks
will vary in the actual words used to describe the different stages of this
method, the ideas are the same. In lab, we are going to use the
language described in the figure below.
THE SCIENTIFIC METHOD
Observations
Questions
Evaluations
Hypotheses
Experiments
Using the Scientific Method:
In today’s lab, we will be working our way through the scientific method
by experiencing nature first-hand. What we learn will be used in every lab we
do for the rest of the semester and beyond.
Today as is any scientific exploration, we will begin by making
observations about the natural world. Observations can be made by using any
of our five senses and are nothing more than descriptive statements. These
often relate to patterns or exceptions to patterns. You will begin to understand
this better as we move through the rest of the lab.
After observations are made, we are able to develop research questions.
These are questions about the observations we have made and can usually be
formed by putting a “why” before our observation or by questioning our
observations themselves.
The third step in the scientific method is forming a testable and
falsifiable hypothesis from our research questions. We then design an
experiment or collect data in support of or that contradicts this hypothesis.
Notice that we do not prove a hypothesis is true by gathering data, but can
only show that a hypothesis is false. Therefore, science relies upon the
development of hypotheses and the subsequent rejection of hypotheses to
advance. The reason we can’t unequivocally demonstrate that any single
hypothesis is true is that there is may be a better model of how the world
works that is also consistent with our observations. Multiple hypotheses are
formed from careful consideration of the processes that may underlie your
field observations and subsequent research question. You will get a chance to
practice creating your own multiple hypotheses later on in lab.
Once we have decided upon the hypotheses we would like to examine,
we can design an experiment that will generate data, which can then be used
to reject some of our hypotheses. Experimental design can be very complicated
and there are whole classes dedicated to the subject, but there are some
important components of any experiment you should be aware of. Perhaps
the most important of which is a control. A control is a segment of the
experiment in which nothing is manipulated. This can help determine natural
levels of variation and provides a baseline from which to compare results.
Another important component of experimental design is random sampling.
Since in a vast majority of situations every inch of land or every individual in a
population is not feasibly accounted for, samples are taken. These are meant to
be representative of the whole population, but in order to make these samples
accurate estimations of the original population, the samples need to be
random and unbiased. And last, but certainly not least is replication. This is
important because with replication comes reliability and repeatability. In field
research, replication is important in order to account for random variations in
the environment so that they will not be seen as patterns or results.
Evaluation is the next step of the Scientific Method and involves
comparing the data generated from your experiment to the predictions made
in your hypotheses. This step often involves statistical testing of your data.
There are often multiple ways to statistically analyze a data set so comparison
of methods is also important in evaluation.
Often, once evaluations have been made of the data collected and
conclusions have been generated, new questions are raised that require further
exploration and the cycle repeats itself. This is how science advances itself and
continues to expand our knowledge in every direction imaginable.
Objectives:
1) To practice using the scientific method first-hand.
2) To learn how scientists seek to improve our understanding of
natural phenomena.
Winter Ecology Walk: Even in winter, life in a forest is bustling with activity, it
just may be hard to see. We will be going to East Woods in Shelburne
to take a look around and see what we can see. While we walk, be sure
to take notes on observations you are making about the forest.
Remember, observations are just statements about what you see, hear,
feel or smell. (We can avoid taste for this lab.) What lets you know that
there are still living things in the forest? Do you see any tracks? Can you
identify them? Do you hear anything? Where would things still in the
forest be living to keep warm?
What step of the Scientific Method is this? What is the next step?
Back in the Lab: Let’s take a look at and share some of the observations we
made on the Winter Ecology Walk. Can observations be put into
different groups? Do any patterns emerge?
The Scientific Method says that after we observe, we should develop
research questions. Look over the examples below and then choose
three of your most interesting observations and turn them into research
questions.
Generating research questions
Generating research questions is easy. In fact, we do it all the time. Each time
you notice a trend or pattern, and each time you wonder 'Why is it like this?"
(or) "Why is this happening?" - you have generated the raw ingredients of a
research question and, ultimately, a research hypothesis. This does not mean,
of course, that all research questions are worth pursuing -- deciding which
question is worth pursuing is another issue entirely. But the essential first step
is having lots of research questions from which to choose. This lab is intended
to help you in this first step of the research effort.
How to do it? In many cases you can simply place a "Why" in front of your
observations. Here are some examples.
OBSERVATION 1: Most of the overstory trees here are evergreen.
RESEARCH QUESTIONS 1: Why are most of the overstory trees here evergreen?
OBSERVATION 2: Most of the understory plants here are ferns.
RESEARCH QUESTION 2: Why are most of the understory plants here ferns?
OBSERVATION 3: Very few of the herbs are producing flowers.
RESEARCH QUESTION 3: Why are very few of the herbs producing flowers?
OBSERVATION 4: It appears that white pines on this site are taller than white
pines on that site.
RESEARCH QUESTION 4: Are the white pines on this site taller than the white
pines on that site?
OBSERVATION 5: I'm not sure, but it seems that periphyton cover is higher in
some reaches of the stream than in others.
RESEARCH QUESTION 5: Is periphyton cover higher in some reaches of the
stream than in others?
The next step in the Scientific Method is perhaps the most important.
We need to turn our questions into testable hypotheses. Complete the
exercise below before turning your own research questions into
hypotheses.
Translating Research Questions Into Research Hypotheses
Generating questions about the natural world is easy, deciding which ones to
pursue is sometimes a bit more difficult (especially if you think you have a
million great things to figure out!). But, once you have chosen a winning
research question, the next step -- translating it into a research hypotheses -also is easy: Simply write down -- in complete, declarative sentence form -what you think the "correct answers" are to your research question.
These will be your hypotheses. Remember that good scientists, like good
detectives, do not put all their eggs in one basket. Instead, they try to identify
all possible "correct answers" (i.e., "multiple hypotheses"). Here are some
hypotheses for the questions above:
RESEARCH QUESTION 3: Why are very few of the herbs producing flowers?
HYPOTHESES:
1) Seasonal input of light on the site is insufficient.
2) People pick them.
3) The plants are not of reproductive age.
4) They produced their flowers earlier in the summer (or they have not yet
produced them).
5) etc.
RESEARCH QUESTION 5: Is periphyton cover higher in some reaches of the
stream than in others?
HYPOTHESES:
1) Periphyton cover is highest on rocky substrates.
2) Periphyton cover is highest in reaches with low stream velocity.
3) Periphyton is lowest where predators are highest.
4) Periphyton is lowest in headwater reaches, lowest in floodplain reaches, and
intermediate in midwater reaches.
5) etc.
For the following research question, develop 4 hypotheses with a partner.
(Remember to introduce yourself first….it’s only polite.)
RESEARCH QUESTION 1: Why are most of the overstory trees observed at East
Woods evergreen?
HYPOTHESES:
1)
2)
3)
4)
Now it’s time for us to turn our own observations and questions into
hypotheses. On the worksheet below, choose two of your selected research
questions and develop three hypotheses or predictions for each one.
With multiple research hypotheses in hand and a great research question
under your belt, you are ready to figure out how to test your hypotheses. But
before that happens, it usually is necessary to think carefully about your
hypotheses. We will help you in this next stage.
Let’s go over as a class how we could test the hypotheses given for Research
Question 3: Why are very few of the herbs producing flowers?
For each alternate hypothesis let’s brainstorm how we would design an
experiment or collect data that could address that hypothesis. Is there a
control? How could we ensure we are collecting good samples?
To help you do this with your own hypotheses here is a quick exercise.
*Take hypothesis #2 of Research Question 5 given above. Draw a graph
of the results you might expect to find. Be sure to label the axis. How do
those axis influence what you need to measure in an experiment?
*Now choose 2 of your own hypotheses and on your worksheet make a
graph of your expected results for each just like you did with Hypothesis
5-2. Then briefly describe to your partner how you would address each.
What variables would be important to include?
Thanks to Jeffery Hughes and Linden Higgens for contributing to this lab.
Name:____________________________
Scientific Method Worksheet:
OBSERVATIONS
1)
2)
3)
RESEARCH QUESTIONS
1)
2)
3)
MULTIPLE HYPOTHESES
1a)
Expected Result Graphs
______
1b)
1c)
2a)
2b)
2c)
______