Download Guppies – Quang Anh

Natural Selection and Sexual Selection Influence On Guppies
Coloration
Aim: To what degree do predation and sexual selection affect guppy coloration?
Hypothesis: If there are mostly bright guppies in an area with a high predation level, then after 10
generations, the gene frequency of the bright guppies will drop drastically to 0.1. The gene frequency of
the bright guppies will decrease tremendously because those guppies don’t have the trait of drabcolored, so the predators will be attracted to them more as they don’t blend in with the environment.
But at the same time, the gene frequency of the bright guppies will not decrease to zero because of the
theory of sexual selection. This theory states that female guppies will be attracted to the bright male
guppies. This means the bright guppies have higher chances of passing down their genes as they are
more attractive and this would result in a certain amount of bright guppies reproduced in every
generation.
Simulation 1: Data Table
Predation Level
High
Medium
Low
Average Beginning
when no guppies
was eaten
Gene Frequency
of Brightest
Guppies
0.12
0.34
0.78
0.43
Gene Frequency of
Bright Guppies
Gene Frequency of
Drab Guppies
Gene Frequency of
Drabbest Guppies
0.15
0.53
0.15
0.33
0.07
0.13
0.08
0.17
0.65
0
0
0.08
Natural Selection and Sexual Selection Influence
on Guppies Coloration
- Simulation 1
0.9
0.8
Gene Frequency
0.7
Gene Frequency of the Brightest
Guppies
0.6
0.5
Gene Frequency of the Bright
Guppies
0.4
0.3
Gene Frequency of the Drab
Guppies
0.2
0.1
Gene Frequency of the Drabbest
Guppies
0
High
Medium
Low
Predation (Level)
Calculation:
The changes in gene frequency of the bright guppies between the beginning and the end:
- High level of predation: 0.15-0.33=-0.18
- Medium level of predation 0.53-0.33=0.2
- Low level of predation: 0.15-0.33= -0.18
The total gene frequency of both the brightest and bright guppies:
- High level of predation: 0.15+0.12=0.27
- Medium level of predation 0.53+0.34=0.87
- Low level of predation: 0.15+0.78=0.93
Conclusion:
Through this simulation, the data shows the effect of both natural and sexual selection. When
the predation level, representing the force that creates natural selection, is high, the gene
frequency of the brightest guppies is 0.12 and for the bright guppies, it is 0.15, dominated by
the gene frequency of the drabbest guppies which is 0.65. This proves that although the bright
color makes the male guppies more attractive and have a higher reproductive success rate,
they are the most easily spotted, not only to the female guppies but also the predators.
Because of that, the rate of bright guppies being is much greater than the reproductive rate of
the guppies, ending up in the gene frequency of the brightest guppies and the bright guppies
reducing drastically.
During this simulation, sexual selection also played an important part and it is most noticeable
during the third simulation, when the predation level is low. During the third simulation, the
gene frequency of the brightest guppies was the highest, at 0.78, and so, it proves that those
are the ones seen as the most attractive by the female guppies. And although the predation,
natural force, played a role in the simulation, it was overwhelmed by sexual selection and even
though the brightest guppies are the most noticeable, their reproductive rate was much higher
than the rate of them getting eaten so their gene frequency still rose to the top.
For this certain simulation, the conjecture is that the sexual selection and natural selection both
played a great role in evolution but for this certain guppies, sexual selection was much more
powerful. This is because when the guppies are evenly mixed in color and the predation level is
medium, the gene frequency of bright guppies was the highest, followed by the brightest
guppies, then the drab and at the end was the drabbest guppies with the gene frequency of 0.
This proves that although the bright guppies are much more noticeable than the drab guppies,
the female guppies find them more attractive and so, their reproductive rates was so high that
they kept on increasing, overwhelming the rate of them getting eaten by the predators.
I believe that although not perfectly correct, my hypothesis was somewhat supported by the
data collected. In the hypothesis, a prediction being made was that the gene frequency of the
bright guppies will by 0.1 while the data shows that it is 0.15. Although the numbers weren’t
exact, they were closely the same, not too different. But in the general view, my hypothesis was
supported by the data, not perfectly. In the hypothesis, it is predicted that the gene frequency
of the bright guppies will decrease tremendously and the data showed the same trend.
Evaluation: I believe that my hypothesis is very testable because of different reasons. The first reason
being that the hypothesis contains specific level of predation (high predation level) and a specific level of
coloration (mostly bright) that the simulation starts with and also the end result (gene frequency of the
bright guppies is 0.1). This is one of the main factors that make the hypothesis testable as it has specific
values that any reader can apply on the simulation. Another reason is because it has a prediction: “the
gene frequency of the bright guppies will drop drastically to 0.1”. This tells the readers whether the
hypothesis is valid or not after they’ve done the simulation. If there wasn’t any prediction then the
readers won’t know if the hypothesis is supported by the data as they don’t know the expected
outcomes for the hypothesis.
This is not a fair test because the data was recorded at different weeks. This means the data is changed
as each week, the gene frequency of the brightest, bright, drab and drabbest guppies would be changed.
It is also not a fair test because for each simulation, the number of each type of guppies is different. An
example of this is when the simulation had high predation level, the gene frequency of the brightest
guppies was 0.49 but when it was with low predation level, the gene frequency of the same type of
guppies was only 0.42. This creates a slight change in the final result and hence, the simulation won’t be
a valid fair test.
I believe that not enough data was collected as there was only one trial for each of the simulation.
Because of this, an average gene frequency for each type of guppies won’t be found as there weren’t
more than two trials. If there was more data collected, I could find the average and more pattern/trend
in the data like how the trials had the same data and what the average changes in the gene frequency is.
More than one trial
Same recording week
Having more than one trial would get more
accurate data and you can find the average which
is much more accurate.
By recording at the same week, it would be a fair
test as there is no change in the time when the
data is recorded in.