Natural Selection Lab Report
Introduction
This experiment is based upon the findings and research on Darwin’s Finches on the Galapagos Islands.
These finches share a common ancestor from the mainland of South America. These finches are all
similar in appearance except for the notable difference in beak types. In an article by Dr. Robert
Rothman it states, “Darwin's finches share similar size, coloration, and habits. Their salient difference is
in the size and shape of their beak “(Rothman 1). It is these beak types that demonstrate
“microevolution” by natural selection and enable others to document and truly understand how the
theory of evolution works. Recent experiments have been conducted on Darwin’s finches by Peter R.
Grant and Rosemary Grant on the effects of evolution and how there are many factors that contribute
to it. “Evolution can be predicted in the short term from a knowledge of selection and inheritance.
However, in the long term evolution is unpredictable because environments, which determine the
directions and magnitudes of selection coefficients, fluctuate unpredictably. These two features of
evolution, the predictable and unpredictable, are demonstrated in a study of two populations of
Darwin's finches on the Galápagos island of Daphne Major.” (Grant 1) This study of Darwin’s finches has
truly opened the doors to understanding evolution and the process of natural selection.
Hypothesis
The Chopsticks will decrease in frequency due to the lack of skill in using them and the bulkiness of the
sticks in picking up the peanuts.
Materials and Methods
Materials
The materials used in this experiment included various “beak types” namely, tongs, clothes pins,
chopsticks, binder clips, tweezers, chip clips, large hair clips, and small hair clips. The food supply was
also provided it being peanuts. A cup and timer were also used in this experiment.
Methods
In this experiment, peanuts were distributed on rows of tables and various “beak types” were handed
out one to each student. The students were then told to grab as many peanuts, one by one, as they
could with their “beak” and to put these peanuts in their stomach (cup). After a minute had gone by, the
students were asked to count how many peanuts they had and then the three students with the lowest
number of peanuts gathered were asked to go stand on the side and the three students with the highest
number of peanuts were asked to go stand on the side with their “beaks.” The students with the lowest
number of peanuts then “died” and their “beak type” did not carry on and they were given another
“beak type” that had been one of the winners since the winners “reproduced” with two offspring with
that same “beak type.” After the round is over the data is recorded on a table and a new round is
started. This process went on for five rounds. However, in the second round a mutation was added, the
small hair clip, in place of a chip clip, but it only survived for two rounds and then died off. At the end of
the experiment the data was collected, and conclusions were drawn.
Results
Narrative Summary
The tongs, clothes pins, and chip clips increased in frequency. The tongs increased by 1, the clothes pins
increased by 5, and the chip clips increased by 3. The chopsticks, binder clips, and large hair clips
decreased in frequency. The chopsticks and binder clips decreased by 4, and the large hair clips
decreased by 2. The small chip clip “mutation” did not survive during the experiment and only remained
for 2 rounds. The tweezers frequency remained the same throughout the procedure staying at 5. The
clothes pins had the most increased frequency success and the chopsticks and binder clips had the
lowest decreased frequency.
Rounds
Natural Selection Beak Experiment
12
10
8
6
4
2
0
Beginning
Round 1
Round 2
Round 3
Round 4
Round 5
Beak Types
Conclusion
The hypothesis stated above is supported in the data results that the chopsticks decreased in frequency.
The data shows a constant decrease in the chopsticks after the first round resulting in only one pair of
chopsticks remaining at the end. A possible error during this experiment may derive from the skill level
of those using the chopsticks although this played a huge factor in the outcome of the experiment.
Other errors that could have occurred would be in the process of the counting. It is highly probable that
one of the students miscounted and another student could have been a “winner” or a “loser” affecting
the overall results of the experiment. A replication of this experiment by other researchers would
evaluate whether or not this experiment and its results are valid by determining from their results
where the errors could be and how the data sample affects the experiment.
Discussion
The scientific method is the process of making an observation or finding a problem, determining a
hypothesis that can be tested and falsified explaining the observation, creating an experiment to test
the hypothesis and to gather data, draw conclusions from the data, communicate the results, and to
have others retest the hypothesis using the same experimental method to evaluate the validity of the
experiment and results.
Some other fields that use the scientific method are: medical, engineering, pharmaceutical, physics,
astronomy, and environmental. All these fields encounter problems or observations in which they need
to make a hypothesis that can be tested and falsified through an experiment. These experiments are
then retested over and over again to provide results and information for decisions to be made upon and
for theories to be based upon.
This activity demonstrated my use of the scientific method because it required me to make an
observation and form a hypothesis. I then tested that hypothesis for falsification and collected data
based on the number of beak types there were remaining in each category after each round. In the end I
was able to draw conclusions and support my initial hypothesis. Others will be able to replicate this
experiment and determine whether my results were valid.
The theory of evolution by natural selection is essentially the survival of those whose genetic variations
are most favorable to the environmental pressures. The favorable variations will increase in frequency in
the population by helping that particular animal survive and compete with others for its needs and then
passing those favorable variations to the next generation. Those who do not have favorable variations
will most likely not survive and pass those variations on to next generation allowing for a natural
selection to occur of those who are most suited for the situation at hand.
This activity supported the theory of evolution by natural selection because it demonstrated how
natural selection would have occurred among Darwin’s finches in a simpler context by having various
“beak types” and having various rounds where competition for food and the “environment” had an
impact on how much food one got. The losers did not reproduce just like how the finches with less
favorable variations did survive and did not reproduce. Over the rounds there began to be an increase in
the “beak types” that were most favorable to grab that particular food item because those traits were
passed on to the next generation showing how the favorable traits increase in frequency over time in a
population.
References
Grant, Peter R. "Unpredictable Evolution in a 30-Year Study of Darwin's Finches." Unpredictable
Evolution in a 30-Year Study of Darwin's Finches. Science AAAS, 26 Apr. 2002. Web. 07 Feb.
2015. <http://www.sciencemag.org/content/296/5568/707.short>.
Rothman, Robert, Dr. "Land Birds." Darwin's Finches. N.p., n.d. Web. 07 Feb. 2015.
<http://people.rit.edu/rhrsbi/GalapagosPages/DarwinFinch2.html>.