"Within just four weeks, the two types of guppies drove the parameters of the artificial streams in very different directions," said Travis, the dean of Florida State's College of Arts and Sciences and a distinguished professor in its Department of Biological Science.
The study is described in the Feb. 1, 2010, online edition of the journal PNAS (Proceedings of the National Academy of Sciences). It was funded by a five-year, $5 million grant from the National Science Foundation's Integrative Biological Research (FIBR) program.
It is essential that scientists better understand the evolution-ecology feedback loop and the surprising speed with which an ecosystem can be altered by adaptations in a species that populates it, said Travis, because so many animals and plants are evolving in response to ecosystem changes caused by humans. As an example, he points to the overharvesting of fish, which can cause some species to get smaller and die younger, which in turn could alter their ecosystem via a feedback loop that might eventually mean no fish to harvest at all.
"Evolution can be very fast," he said. "When our research team started this project, we already knew that downstream guppies mature earlier, make more and smaller babies, have less colorful males, and tend to be more carnivorous and less herbivorous than upstream guppies. Past work by David Reznick, our study's principal investigator, showed that if you take downstream guppies and introduce them to pools upstream with no guppies, the descendents of those founders will evolve to look like upstream guppies in a few dozen generations."
Travis and team hoped that their experiment would reveal whether the two types of guppies, upstream and downstream, were different enough that switching out one for the other would cause substantial changes in ecosyste
|Contact: Joseph Travis|
Florida State University