Feature Investigation Summary
Ole Seehausen and Jacques van Alphen did an experiment with P. pundamilia and P. nyererei, which are two types of African Cichlids. They noticed that in certain lakes the two species will interbreed, while in others they will not. They noticed that though the two species are very distinct, they look basically identical under an orange monochromatic light. Seehausen and van Alphen did a series of tests with a female from one of the species and two males (one from each species) in a fish tank. They wanted to see whether the type of lighting would affect the females' choice. They noticed that females of both species typicallly preferred males of their own species when the tank was lit with normal light. However, the females lost that preference and were drawn to males of either species under the orange monochromatic light. We can connect these results to the real life situation. One can draw the conclusion that some lakes have "normal lighting" while others have light conditions with the same effect as the orange monochromatic light. This is what would cause the two species to interbreed in some lakes, but not in others. This experiment is important because it shows how much of an effect the environment can have on a species. The light conditions are single handedly causing two species to become increasingly distinct from each other.
Powerpoint Presentation
Virtual Lectures
Useful Materials
This website is about identifying what kind of Cichlid you might have. This is pretty interesting. It gives a picture of how many different types of Cichlids there are and how different they are from each other.
Speciation Through Sensory Drive in Cichlid Fish
This is more work from Seehausen. Though it talks about this experiment, there is no mention of van Alphen. It talks about how the experiment is a type of speciation through sensory drive.
 |
| A side by side comparison of Cichlids in Lake Malawi and Lake Tanganyika. |
 |
| An anatomical diagram of the Malawi Cichlid. |