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Different Types of Bird Beaks in Helianthus annuss
(Sunflower) Seed Environment
By: Cindy Giang
Introduction
Charles Darwin, the “father” of evolutionary thoughts ("History of Evolutionary Theory,
The”, 2016), set sail in 1831 on the Darwin’s voyage, for five years. On his journey he observed
and documented many different types of species that shared similar traits, (“Darwin's Great
Voyage of Discovery.", 2016). He also realized that birds in different food source areas had
different beak shapes, for example tree finches were insect eaters and ground finches grazed on
seeds, (“Adaptive Radiation: Darwin’s Finches”, 2016). Therefore, “Density variation in bone
can be expected and might result in a locally higher strength at high stress locations…” (Soons,
2015) this shows that beaks are indeed shaped to resist forceful feeding on harder food sources
from different places.
After many years of research and studies Darwin proposes that population of species is
determined by something he called “Natural Selection”. Natural Selection states
“Favorable/unfavorable variations increase/decrease in frequency in a population” (M.Schaefer,
Professor, 2016). A good example of natural selection would be, “Small host populations of
endemic species [remains] particularly vulnerable because extinction can occur before the hosts
have a chance to evolve effective defenses” (Cimadom, 2014).
Another factor to include in
this experiment is Malthus’ theory; he stated “Population growth would exceed resource growth,
leading to catastrophic checks on overpopulation, (“Malthus' Theory of Population Growth”,
2015). If food source were endless then bird beaks in any given environment would have little to
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no importance because competition is not necessary. Therefore, Malthus theory is a critical
source to Darwin’s Natural Selection theory.
Students in Anthropology 1020 from Salt Lake Community College decided to do the
“Bird Beak in Helianthus annuss (Sunflower) Seed Environment” experiment because they
wanted to personally see the result of natural selection first handed.
Hypothesis
If bird beaks are related to the bird’s survival ability in a given sunflower seed
environment, then Tweezers-Beaked birds will have a higher frequency in the population. This
hypothesis is developed by the beak’s mobility. After observing all the samples, TweezersBeaked seems to have the quickest open/close motion compared to the rest of the samples.
Materials and Methods
Materials
35 - Students
35 - Chairs
35 - 3 Ounces Paper cups
10 - Chopsticks (Pairs)
10 - Clothes Pins
10 - Large Hair Clips
10 - Tweezers
10 - Small Hair Clips
10 - Chip Clips
5 - Binder Clips
5 - Tongs
4 – Rows of Desk (19 Desks)
1 – Sunflower Seed (Large Bag)
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Methods
The experiment area was set up according to the guidelines in order to control the food
placement and flow of traffic when birds attempt to migrate from table to table. It is critical to
mimic the environment for each test to get the most accurate result possible. There will be four
rows of tables, the first three rows will have five tables and the last row will have four tables.
Each row should be placed approximately two and half feet away from each other, leaving space
for chairs. Place two chairs next to each table, which create space for the students to sit down
during the experiment. Spread 1/3 to 1/2 bag of sunflower seed unevenly throughout the rows
and tables. Let the students sit randomly and pass out bird beaks.
For the control round, there will be five students testing the same beak type except for
Chip Clips (start with four) and Tongs (start with zero). Give each student a cup for the
sunflower seeds; the cup will act as the bird’s stomach. For each round the students will have
one-minute to quickly use their beak type to pick up and place the sunflower seed, one by one, in
to the paper cup as fast as they can.
After the control round, let the student count how many sunflower seeds they have
collected within that one-minute window. Ask the three students with the lowest, and the three
students with the highest amount of sunflower seeds to come up to the front of the classroom.
Revoke the three lowest beaks from the population and match the three highest beaks, this will
double the number of winner beaks in the population; this is an example of survival of the fittest
and reproduction success.
Repeat the control round for rounds one through five, however do not reset the number of
beaks after each round continue with the number of beaks that was provided from the previous
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round. After round one, add the Tong-beaked bird type into the pool. Remember to record your
data after each round to for accuracy.
Results
Data
Beak
Chopsticks
Clothes Pins
Hair Clips (L)
Tweezers
Hair Clips (S)
Binder Clips
Chip Clips
Tongs
Total
Table 1.1 Beak Testing with Sunflower Seeds
Control
Round 1
Round 2
Round 3
Round 4
5
5
4
3
2
5
4
4
2
2
5
5
6
7
7
5
7
8
10
11
5
5
5
5
5
5
4
2
2
2
4
4
5
5
5
1
1
1
34
34
35
35
35
Beak
Chopsticks
Clothes Pins
Hair Clips (L)
Tweezers
Hair Clip (S)
Binder Clips
Chip Clip
Tongs
Table 1.2 Frequency Differences
Round 5
Control
Difference
5.71
14.29
-8.58
5.71
14.29
-8.58
20
14.29
5.71
34.29
14.29
20
11.43
14.29
-2.86
5.71
14.29
-8.58
14.29
11.76
2.53
2.8
2.8
Graph 1.1 Beak Testing with
Sunflower Seeds
14
12
10
8
6
4
2
0
Control
Round 1
Round 2
Round 3
Round 4
Round 5
Round 5
2
2
7
12
4
2
5
1
35
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Graph 1.2 Frequency Differences
25
20
15
10
Population Increase
5
Population Decrease
0
-5
-10
-15
Analysis
The test comparing birds with different beaks concluded, Tweezers-Beaked birds are the
best fit for sunflower seed environments. Refer to Table 1.1 for data collected or refer to Graph
1.1 for a visual understanding of the experiment. Data in Table 1.2 suggest that larger negative
(red) differences determine a population decrease, while a greater positive difference (green)
shows a growth in population. However, Tong-Beaked birds display a special scenario. The
control group originally started with zero Tong-Beaked but as time went by the new species was
introducing to the environment. Graph 1.2 also shows a common decrease between Chopsticks,
Clothes Pins and Binder Clips- Beaked, which suggest that these types of birds are not ideal for
the environment and there is a possible tie between these species due to their drastic decrease in
population.
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Conclusion
In conclusions, the most effective specie for the given environment would be the one that
shows a strong increase in the population for the given time frame, five rounds. In this
experiment, the Tweezers-Beaked birds had the most population growth, for the environment
provided, followed by Hair Clips and Chip Clips-Beaked. After the following experiment it
proves that the original hypothesis, if bird beaks are related to the bird’s survival ability in a
given sunflower seed environment, then Tweezers-Beaked birds will have a higher frequency in
the population, is correct.
The data collected from the experiment is valid to a certain point. For example, food
sources were limited like Malthus theory states so it mimics the realistic habitat. However, there
is always room for improvement in all experiment. Human error is a great factor in this
experiment, for example some students was picking up each seed aggressively while others
peacefully acquire each individual seeds with grace, sometimes it’s not now affective the tool is
but how the user approaches it. Various samples of birds will adapt to the environment
differently therefore more samples should be gathered for an improved experiment.
Discussion
The theory of evolution by Natural Selection states that species with the advantage in
their environment are more likely to survive and produce offspring, while those who are poorly
fitted will be eliminated therefore their chance of producing and passing on the genes to
offspring are limited due to death.
Natural Selection: Tweezers-Beaked birds, favorable variation, will increase in frequency in
population over time.
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Natural Biological Variation: The Tweezers-Beaked Birds is the most favorable with the
sunflower seed environment.
Inheritance: Tweezers-Beaked is inherited their genes from their best-fit parents.
Competition: In ever generations there are more Tweezers-Beaked birds’ produce than
survival.
Individual: Tweezers-Beaked birds are more likely to survive in a sunflower seed environment
and produce more offspring due to their beak shape advantage.
In this activity the theory of evolution was used to imitate natural selection. The bird
beaks with the favorable trait, inherited from their parents, enable them to have a better
advantage against their peers when they are seeking for food. In this experiment, students used
different types of tools to mimic different beak types and eliminated the ones that lagged behind,
survival of the fittest. Beaks that benefit the environment will live to reproductive age producing
more offspring, however each generation will produce more offspring but not all will live.
Therefore, beaks that develop the favorable trait to the sunflower seed environment prove that
natural biological variation is factual.
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References
"Adaptive Radiation: Darwin's Finches." PBS. Clear Blue Sky Production, Inc., n.d. Web.
29 Jan. 2016.
Cimadom, Arno, Angel Ulloa, Patrick Meidl, Markus Zöttl, Elisabet Zöttl, Birgit Fessl,
Erwin Nemeth, Michael Dvorak, Francesca Cunninghame, and Sabine Tebbich. "Invasive
Parasites, Habitat Change and Heavy Rainfall Reduce Breeding Success in Darwin's
Finches." PLoS ONE 9.9 (2014): 1. Web. 04 Feb. 2016.
"Darwin's Great Voyage of Discovery." PBS. Clear Blue Sky Production, Inc., n.d. Web.
29 Jan. 2016.
"History of Evolutionary Theory, The." Science NetLinks. AAAS, n.d. Web. 29 Jan.
2016.
“Malthus' Theory of Population Growth.” Boundless Sociology. Boundless, 21 Jul.
2015.Web. 05 Feb. 2016
Melissa Schaefer, Ph.D, Professor. Jan. 2016.
Soons, Joris, Annelies Genbrugge, Jeffrey Podos, Dominique Adriaens, Peter Aerts, Joris
Dirckx, and Anthony Herrel. "Is Beak Morphology in Darwin’s Finches Tuned to Loading
Demands?" PLOS ONE PLoS ONE 10.6 (2015): 10. Web. 04 Feb. 2016.