Download Darwin`s Finches and Natural Selection in the Galapagos

Chandler Midgley
Human Origins Mon. and Wed. 8:30-10:50
Title:
Darwin’s Finches Lab Report/ ePortfolio Signature Assignment
Introduction:
A finch is a species of bird very common in the Galapagos Islands – a group of
islands along the coast of Ecuador. These birds play a huge roll in Charles Darwin’s
theory of natural selection. In 1835, Darwin visited the islands for about five weeks.
During these weeks, he studies the different kinds of finches that were on different
islands. He noticed that the birds were slightly different depending on which island
he was on, but the birds were all still from the same species. Darwin noticed that the
birds had adapted their beak shape to fit their diet. Birds that ate insects generally
had longer, thinner beaks, and birds that ate seeds and nuts had shorter, wider
beaks. [1]
On the Galapagos Islands, one team of volunteers is researching how Finches are
still evolving. With the introduction of the Philornis downsi fly, which have been
present on the islands since the 1960’s. These flies lay eggs in the Finches nests and
eat the blood and tissue of the young birds. These researchers have noticed that
anywhere between 30-98% of all Finch chicks die each year. [2] The research
focused on two related issues:

How best to control the Philornis parasite

How physical changes due to Philornis are shaping evolutionary change in
Darwin’s finches.
Although this study is ongoing, they have increased their volunteer numbers to
monitor more birds and they are using tactics to control the Philornis downsi fly and
help the finches from going extinct.
Hypothesis: The chopsticks will be the least successful and be the first beaks
to go extinct.
I chose this hypothesis because I believe it will be harder to pick up seeds
with a longer, very narrow beak. Also, that it will be much easier to pick them up
with a shorter, wider beak.
Materials and Methods:
In class, we performed a Natural selection activity with all thirty students. Each
student was given their own “beak” and had to pick up seeds from the table. The
three students with the most seed at the end of 90 seconds would “pass their beak
to their offspring.” Meaning that they would keep their beak, but also give one to one
of the three people who got the least seeds, who would lose their original beaks. We
did this for 5 rounds.
The 7 (8 after a mutation) beaks were as follows:

5 Chopsticks

5 Large hair clips

2 Small hair clips

5 Clothes pins

5 Chip clips

5 Tweezers

3 Tongs

1 Binder clip (an unfavorable mutation in round 3)
Results:
Findings for each round:
Beak Type
Beginning
Round 1
Round 2
Round 3
Round 4
Round 5
Chopsticks
#5
#3
#2
#1
#1
#1
Freq: 17%
Freq: 10%
Freq: 10%
Freq: 3%
Freq: 3%
Freq: 3%
Lg. Hair
#5
#6
#6
#5
#5
#4
Clips
Freq: 17%
Freq: 20%
Freq: 20%
Freq: 17%
Freq: 17%
Freq: 13%
Sm. Hair
#2
#2
#2
#2
#2
#2
Clips
Freq: 10%
Freq: 10%
Freq: 10%
Freq: 10%
Freq: 10%
Freq: 10%
#4
#4
#3
#1
#1
Freq: 17%
Freq: 13%
Freq: 13%
Freq: 10%
Freq: 3%
Freq: 3%
#5
#7
#9
# 10
# 11
# 11
Freq: 17%
Freq: 23%
Freq: 30%
Freq: 33%
Freq: 37%
Freq: 37%
#5
#5
#3
#4
#4
#5
Freq: 17%
Freq: 17%
Freq: 10%
Freq: 13%
Freq: 13%
Freq: 17%
#3
#3
#4
#4
#6
#6
Freq: 10%
Freq: 10%
Freq: 13%
Freq: 13%
Freq: 20%
Freq: 20%
#1
#0
#0
Freq: 3%
Freq: 0%
Freq: 0%
Clothes Pins # 5
Chip Clips
Tweezers
Tongs
Binder Clips
Not
Not
Not
Present
Present
Present
Binder Clips
Tongs
Tweezers
Round 5
Round 4
Chip Clips
Round 3
Clothes Pins
Round 2
Sm. Hair Clips
Round 1
Beginning
Lg. Hair Clips
Chopsticks
0
2
4
6
8
10
12
Beginning
Chopsticks
Lg. Hair Clips
Sm. Hair Clips
Clothes Pins
Chip Clips
Tweezers
Tongs
5th Round
Chopsticks
Lg. Hair Clips
Sm. Hair Clips
Clothes Pins
Chip Clips
Tweezers
Tongs
As shown in the above chart and graphs, the chip clips were the most
effective in picking up the seeds. It was a tie between chopsticks and clothespins for
the least effective, both ending with one remaining of each.
Conclusion:
My hypothesis that chopsticks would be the least effective in picking up
seeds was proved correct. Chopsticks tied with clothespins for last place, both
ending with only one after starting with two.
There are several different factors that contributed to this study. Mostly, is
that everyone is at a different skill level with their beaks. For example, several
people didn’t even know how to use chopsticks, while others were very skilled with
them. Also, the number of seeds available affected the outcome a little. Some people
had more seeds in front of them, and some had to go elsewhere to find seeds. Some
beaks also provided protection from other people trying to steal their seeds.
Discussion:
The Scientific Method is a very important method to use when researching
anything.
The steps are as follows:

Observation/Research

Hypothesis

Prediction

Experiment

Conclusion
By using these five steps, ideas become more thought through and calculated, and
are proven correct or false. Almost every field in science uses the Scientific Method;
in fact, anyone who is trying to test anything out should be using it.
In this experiment, we used the Scientific Method to make an educated guess
on what beak would me the most or least effective for picking up seeds. We then got
to test it out and see the results for ourselves. After, we got to make conclusions
about what we saw happen, and state if our hypothesis was correct or incorrect.
The theory of Natural Selection explains that animals adapt to their
surroundings to survive. Throughout time, almost all species (if not all) have
adapted in one way or another to their surroundings. The Finches on the Galapagos
Islands are a good example, but not the only one. It is believed that Giraffes once had
shorter necks, but grew longer necks as the need to reach the leaves on the top of
trees increased. However, the example that makes it clear to me is that of the field
mice in New Mexico.
Tan field mice in a specific region of a New Mexico desert were very common,
because the tan grass and dirt would camouflage them from predators. But when
they would go onto the black lava rock that was also a big part of that region, they
would stand out to predators. Researchers noticed a rice in grey mice on the lava
rock. The mice had adapted to their surroundings and had started breeding dark
mice to protect them from predators when they lived on the lava rock.
The underlying assumptions of Natural Selection are as follows:
1. Natural Biological Variation – Favorable, Unfavorable, Neutral
2. Inheritance
3. Competition for Survival – There are more living things than there are
resources
4. Individuals with favorable variation are more likely to survive and leave
more offspring.
This activity was the perfect opportunity to explain Natural Selection. It showed that
the animals who are less able to obtain resources will die out and the ones who are
able to obtain more will thrive and have a lot of offspring. The offspring will
generally get some of the same traits as the original animals (like beak shape) and
also thrive and have a lot of offspring. Therefore, in that certain region, there will be
animals that are more adapted to living there and thriving.
References:
[1] "Darwin's Finches." Darwin's Finches. Truth in Science. Web. 29 Jan.
2015. <http://www.truthinscience.org.uk/tis2/index.php/evidence-forevolution-mainmenu-65/53-darwins-finches.html>.
[2] "Darwin's Finches and Natural Selection in the Galapagos." Darwin's
Finches and Natural Selection in the Galapagos. 1 Jan. 2014. Web. 30 Jan.
2015. <http://earthwatch.org/expeditions/darwins-finches-and-naturalselection-in-the-galapagos>.