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Sex and the Single Guppy

Intro | Discovery | Hypotheses | Simulation 1 | Analysis 1 | Simulation 2 | Analysis 2 | Conclusion | Gallery

Analysis of Simulation One:

Your settings:

Initial population: Mostly drab
Predators: 30 rivulus

After maintaining our simulation pool for about two years, we find that the composition of the population has changed considerably. Not only have guppy numbers more than doubled under the relatively low level of predation, but also, after only four guppy generations, the percentages of drab males to bright males have evened out considerably.

Number of guppies: 227
Number of generations: 5
Number of weeks: 112
Male color types:
    Brightest: 42%
    Bright: 7%
    Drab: 18%
    Drabbest: 34%

guppy simulation after 2 years

After 12 guppy generations, the pendulum has swung heavily in favor of the brightest males, who now make up more than 70 percent of the guppy population. Endler observed these trends in the headwater pools where there are relatively few predators.

Number of guppies: 232
Number of generations: 12
Number of weeks: 407
Male color types:
    Brightest: 95%
    Bright: 1%
    Drab: 3%
    Drabbest: 2%

guppy simulation after 12 generations

Can you tell yet what is happening? Or why? How about examining another simulation with a different set of guppies and predator fish to find out?

-> Go to another simulation

Intro | Discovery | Hypotheses | Simulation 1 | Analysis 1 | Simulation 2 | Analysis 2 | Conclusion | Gallery

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