Evolutionary Processes Influence Ecology

Researchers have believed for a long time that species adapt, evolve, split, endure or disappear based on interactions with their ecosystems. In other words, the interaction between organisms and their environment, commonly known as ecology, shapes evolution. But many scientists have proposed over the years that the opposite also holds true, in the sense that the various species living in a certain ecosystem can influence that particular ecosystem as well. Now, a new research funded by the US National Science Foundation (NSF) lends further credence to that hypothesis.

The data basically provides a new template for understanding the intricate nature of the relationships that exists between evolution and ecology, and takes this field of study to an entirely new level. Details of the work presenting this fundamental shift in science appear in the latest online early edition of the respected journal Proceedings of the National Academy of Sciences (PNAS).

“By documenting that rapid, adaptive evolution within single species can cause substantial changes in ecosystem structure and function, this study makes a significant contribution to merging ecological and evolutionary theory,” the Program Director of the NSF Division of Environmental Biology, Alan Tessie, explains. The Deb provided the funding for this investigation, which was conducted by researchers at the University of California in Riverside (UCR). The group was led by evolutionary biologist David Reznick.

“Our results represent a first significant step in showing that evolution cannot be ignored when studying ecological interactions,” the expert says. In a series of studies, the researchers constructed two artificial streams alongside two natural streams. The original bodies of water featured small fish known as guppies that lived in very different ecosystems. One of the streams had predatory species in it, whereas the other had none. Fish from both these streams were then placed in the artificially constructed ones, which had the same make-up in terms of the invertebrates and algae they contained.

“Guppies from the more diverse fish communities ate more insect larvae, while the low-predation guppies – guppies from the simple fish communities – ate more algae. These differences in diet resulted in the artificial streams with guppies from diverse communities having more algae and fewer invertebrates than streams stocked with guppies from the simple communities,” UCR scientist Ronald Bassar, who has been the first author of the journal entry, explains.

“By doing our experiments in artificial streams we are able to pin down guppies as a likely cause of what we see in natural streams. The experiments show that local adaptation causes the evolution of differences in diet, which, in turn, causes differences in ecosystem structure. Our next step is to characterize how this changed ecosystem, in turn, shapes how the guppies adapt to it,” Bassar concludes.