New York: Dismissing the common perception that evolution happens only over time, a team of US researchers says they have observed an episode of evolution happening under their nose.
In research with a population of guppies, the scientists observed male colour patterns impacting their ability to make babies and survive longer.
Working in a river in Trinidad, the researchers determined which male guppies would contribute more offspring to the population as well as which would live longer and which would have a shorter lifespan.
"We are detailing how evolution happens," said David Reznick, professor of biology at University of California, Riverside.
"Usually people look at evolution as change over time but they do not know the details of how it changes," Reznick noted.
The new work is part of research that Reznick has been doing since 1978.
It involved transplanting guppies from a river with a diverse community of predators into a river with no predators - except for one other fish species, an occasional predator - to record how the guppies would evolve and how they might impact their environment.
To do this, the team used scales from the guppies to archive their DNA.
When they returned the guppies to the river and new unmarked guppies showed up, the latter were marked and samples of their scales were taken for study.
In this way the team tracked the guppies' differential success in making babies and surviving.
"We could look at their appearance and see how male colour pattern affected their ability to make babies or to survive," Reznick said.
The research also found that males with more or larger orange and black spots produce more offspring, while males with black spots have a higher risk of mortality.
"People think of evolution as historical. They do not think of it as something that's happening under our nose. It is a contemporary process. People are skeptical; they don't believe in evolution because they can't see it. Here, we see it. We can see if something makes you better able to make babies and live longer," Reznick said.
Reznick emphasized that evolution is not a linear process.
"It is a series of episodes," he said.
The findings appeared online in the journal Proceedings of the Royal Society B.