[49th]

It's happening....

An interesting example of evolution at work is the case of the hawthorn fly, Rhagoletis pomonella, which appears to be undergoing sympatric speciation. Different populations of hawthorn fly feed on different fruits. A distinct population emerged in North America in the 19th century some time after apples, a non-native species, were introduced. This apple-feeding population normally feeds only on apples and not on the historically preferred fruit of hawthorns. The current hawthorn feeding population does not normally feed on apples. Scientists are investigating whether or not the apple-feeding subspecies may further evolve into a new species.

Some evidence, such as the fact that six out of thirteen alozyme loci are different, that hawthorn flies mature later in the season and take longer to mature than apple flies; and that there is little evidence of interbreeding (researchers have documented a 4-6% hybridization rate) suggests that this is occurring. The emergence of the new hawthorn fly is an example of evolution in progress.

[DonaldC]

Interesting example of adaptation, not evolution.

[JSDude1]

Yeah, but the same example that you sighted is an example of of the "loss of genetic information" in both populations, and they are (neither of them) significantly different from the original hawthorn fly; there is no new species because there hasn't really been a change in kind (and additional genetic information), only a loss, only a difference.