IB Bio HL
Sex and the Single Guppy – a investigation
Research Question: How does the colour of a guppy affect the population size with 30
acra and 30 rivulus as predators over 8 generations of
Independent Variable: The colour of the guppy and the concentration of that colour in the
Dependent Variable: The population of guppies left after 8 generations of being in the
Controlled Variable: The amount and type of predators used (30 rivulus and 30 acra)
Observations: The results would differ each time when running the simulations, sometimes
slightly, but in order to get the most precise results, 3 simulations had
to be run. After that I took an average, so the results were reliable.
This is the data I collected from watching the simulations. After recording this, i then averaged all the data to form the table below. [pic]
The table shows the overall growth of population, as well as the colour ratio dependent growth. The red bar shows the growth of population with an even mix at the start of the simulation, the blue one shows an mainly bright mix.
If the population starts with an even mix, the overall growth after 150 weeks is lower than if you start with an mainly bright mix.
Furthermore it is noticeable that, if you start with a mainly bright mix the brightest and the bright guppies will breed more than the others. If you start with an even mix, the amount of the brightest and drab guppies will exceed the amount of the brightest guppies.
This has its reason within the fact that the brightest guppies are more likely to breed than the other guppies. But since they are also more likely to be eaten by the predators, they will not exceed the number of bright guppies. Therefore the mixture of guppies in the beginning affects the colour ratio of guppies.
If we assume that the...
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