Wednesday, October 27, 2010

Guppies

1. If being flashy and colorful attracts predators, why do you think guppies are so colorful?

Guppy populations are evolving to more closely match or stand out from their environment.

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.

Guppy or millions fish, Poecilia Reticulata, Brazil. Large patch of shiny black coloration on the top of its back, yellow, white, green, and red spots throughout the bottom of the bottom and fin.


3. After viewing the predator gallery, pick the fish you find most interesting. What is the fish’s common name, scientific name, and origin?
Fat Sleeper, Dormitator maculatus, Southern North America, Bahamas, and Latin America
4. View the guppy’s habitats, what habitat conditions would affect the predator populations?

Some habitats that would affect that predator population most would be the dams which keep out predators so they can't reach the guppies and some of the smaller deeper lakes/ponds would keep lots of guppies as well as predators.


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 a professor who is also a ethologist and evolutionary bioligist noted for his work on the adaptation of vertebrates to their unique environments
6. For each of the three stream areas, describe the guppy coloration:

Pool 1: Brightly multi-colored with large spots. Pool 2: Medium coloration on body and tail, with medium-sized spots. Pool 3: Drab coloration, very small spots concentrated near tail.

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)

Predators are causing guppy generations to become more drab by preying on the most brightly-colored individuals and eliminating them from the gene pool.




Guppy Simulation


% of Brightest Guppies
(10 generations)

% of Bright Guppies
(10 generations)
% of Drab Guppies
(10 generations)
% of DrabbestGuppies
(10 generations)

Trial 1

Guppy: Even Mix
Predators
: 30 Rivulus

42%
25% 28% 5%

Trial 2

Guppy: Even Mix
Predators
: 30 Rivulus, 30 Acara

43%
41% 16%
0%

Trial 3

Guppy: Even Mix
Predators
: 30 Rivulus, 30 Acara, 30 Cichlid

2%
0%
8%
90%

Trial 4

Guppy: Mostly Bright
Predators
: 30 Rivulus

75%
20%
4%
1%

Trial 5

Guppy: Mostly Drab
Predators
: 30 Rivulus, 30 Acara, 30 Cichlid

0%
0%
7%
93%

Summary

8. Describe how predators influence guppy coloration.

Predators influence guppy coloration because the predators eat the brightest most colorful guppies therefore the guppy coloration is slowly leaning towards the drab side.

9. Was your hypothesis correct, use your data to justify your answer.

Our hypothesis was correct because the predators eating the brightest fish cause the population of them to fall while the drab population rizes.

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 while being bright and attracting mates, they also attract predators so they are stuck between mating and being pray to other fish.


11. Why do you think guppies in different areas of the stream have different coloration?

The further down the stream the drabber the guppies get because the lower they are the fewer predators that are able to reach that area. If you go to the top of a stream fewer predators will be there so there will be more bright guppies.


12. What would happen to mostly drab guppies that were placed in a stream with very few predators?

They would most likely survive a long time because they won't stand out as much as other bright guppies.

13. What would happen to brightly colored guppies that were placed in a stream with many predators?

They would most likely be eaten soon after and the drabbest of those guppies would survive the longest time.

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