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Evolution much faster than previously assumed

It has taken lake cichlids in Nicaragua just 100 generations and the same number of years to evolve an entirely new physical feature: very fat lips perched on a narrow, pointy head. These evolutionary processes observed by Professor Dr. Axel Meyer, Head of the Department of Zoology and Evolutionary Biology at the University of Constance, in a remote crater lake in Nicaragua, are a lot faster than they were previously believed to be. The team of researchers from Constance, Ireland and Australia have shown that evolutionary change can happen within a few decades.

It has taken lake cichlids in Nicaragua just 100 years to evolve fat lips perched on a narrow, pointy head. © University of Constance

The fat-lipped fish occupy a different ecological niche from their thin-lipped cousins despite living in the same lake. The researchers found that the different types of fish do not eat the same diet. Observations of captive fish in a tank suggest that the fish avoid mating with each other, although laboratory experiments show that they can still interbreed. “If they also avoid mating with each other in the wild, which is most probably the case, they are well on the way to becoming two different species,” said Professor Meyer.

The new fish variety has a narrower, pointy head, which is ideal for extracting insects and larvae from crevices in volcanic rock. The fat lips act as a kind of protective cushion against the sharp crags. The thin-lipped variety has sturdier jaws and extra teeth to crack the shells of the snails they feed on.

"It is important for scientists to catch incipient species in the process of divergence, otherwise visualising the process in action would be difficult. This new work nicely matches theories that were developed in the 1990s suggesting that new species were able to develop rapidly even when they share the same environment as other species,” said Todd Streelman, evolutionary scientist at the Georgia Institute of Technology in Atlanta, commenting on the Constance researchers’ findings that were recently published in the journal BMC Biology.

Original publication:
Elmer, K. R., Lehtonen, T. P., Kautt, A. F., Harrod, C. & Meyer, A.: "Rapid sympatric ecological differentiation of crater lake cichlid fishes within historic times", in: BMC Biology 2010, 8:60 download from: www.biomedcentral.com/1741-7007/8/60/abstract

Further information
Prof. Dr. Axel Meyer
University of Constance
Department of Zoology and Evolutionary Biology
Universitätsstraße 10
78464 Konstanz
Tel.: +49 (0)7531 / 88-4163
E-mail: Axel.Meyer(at)uni-konstanz.de

Website address: https://www.gesundheitsindustrie-bw.de/en/article/press-release/evolution-much-faster-than-previously-assumed