1. If being flashy and colorful attracts predators, why do you think guppies are so colorful?
Guppies are very colorful so they can attract female guppies and mate.
2. After viewing the guppy gallery, pick the fish you find most interesting. What is the fish’s scientific name, origin and average size? Describe the coloration of the fish you chose.
Common Name: Guppy or Millions Fish
Scientific: Poecilia reticulata
Ave. Size: 1.4" or 3.5 cm
Coloration: Navy blue base, mottled pink, orange, and green. It has a green fin and bright fanned out tail.
3. After viewing the predator gallery, pick the fish you find most interesting. What is the fish’s common name, scientific name, and origin?
Common Name: Pike cichild
Scientific: Crenicichla alta
Origin: Trinidad and Latin America
4. View the guppy’s habitats, what habitat conditions would affect the predator populations?
If the habitat is a deep stream, then the predator populations will be very high. In a small dam habitat, predator populations would be little to none because there would be no room for predator movement. In a medium-small dam there would be a bearable predator population because there would be more room for predators to move around. Only small predators such as the rivulus could prosper in a shallow stream habitat.
Endler’s Discovery and Variations of Guppy’s in Pools
5. Who is John Endler? What did he study and where did he study it?
John Endler is an evolutionary biologist who studied Trinidad's wild guppies, probably in Trinidad. He studied guppie distribution, size, color, and spot sizes.
6. For each of the three stream areas, describe the guppy coloration:
Pool 1: The average male coloration would be very bright with lots of colors and large spots. There were very few predators, so guppies are able to have as flamboyant colors as they want.
Pool 2: In this pool there is a moderate predator population, so the average color is medium on the body and tail with medium spots.
Pool 3: There is very dull coloration in the guppies here because there is a high predator population. This means the guppies need to keep the colors and vibrancy to a bare minimum.
7. Develop your own hypothesis about guppy coloration. The hypothesis should answer the questions: Why do guppies in different areas of the stream have difference in coloration? (You can choose from the list on the simulation, or make up your own)
If there is a higher predator population in one area, then the guppies need to have a drabber/duller coloration because they will be eaten if they stand out too much.
If there is a lower predator population in another area, then the guppies can have very bright colors because they won't be eaten as frequently.
If the predator population is medium then so is the guppy coloration because they may be eaten or they may not.
Guppy Simulation Summary
% of Brightest Guppies
|% of Bright Guppies |
|% of Drab Guppies |
|% of DrabbestGuppies |
Guppy: Even Mix
Guppy: Even Mix
Guppy: Even Mix
|23%||13% ||16%||48% |
Guppy: Mostly Bright
Guppy: Mostly Drab
8. Describe how predators influence guppy coloration.
Predators influence the guppy coloration by making it brighter or drabber. If the predator population is high, then the guppy coloration is dull. If the predator population is low, then the guppy coloration is vibrant.
9. Was your hypothesis correct, use your data to justify your answer.
Yes it was correct because the data showed exactly what we had predicted. The coloration of the guppies was brighter with a smaller predator population. The coloration was also duller with a higher predator population. Lastly, when there was an even predator/guppy population there was medium coloration.
10. What does it mean that “male guppies live in a crossfire between their enemies and their would be mates”?
It means that male guppies live in situations where certain things are conflicting. For example they can either have a good fitness by being very bright and mating. Or they can be very dull and be able to camouflage from their predators. They can have one or the other, not both. So to be able to mate they are in danger of being spotted and becoming prey. By being dull they are in danger of not attracting a mate.
11. Why do you think guppies in different areas of the stream have different coloration?
The higher predator population in one area, the guppies need to have a drabber/duller coloration because they will be eaten if they stand out too much. The lower predator population in another area, the guppies can have very bright colors because they won't be eaten as frequently. The predator population is medium then so is the guppy coloration because they may be eaten or they may not.
12. What would happen to mostly drab guppies that were placed in a stream with very few predators?
They probably would be overpopulated because they would not have a high chance of being eaten by a predator anyways since they are so drab, but now that there are so few predators there would be an abundance of drab guppies.
13. What would happen to brightly colored guppies that were placed in a stream with many predators?
Their population might diminish because their flamboyancy would attract predators, and since there are a lot of predators, there will be very few guppies. Since they will all be eaten.