Frequently, anti-evolution proponents criticize the lack of direct evidence for new speciation.  While the Talk Origins website has some good examples, they're a little unsatisfying.  My question is about a possible experiment. Suppose a population of a species with a relatively fast generation time (e.g. bacteria or possible fruit flies or somethjing like that) were split into two different groups, and then those two groups were placed in increasingly different environments (temp., pH, salinity, sunlight, food source, etc.), gradually so as to select for the individuals best able to survive the gradual change.  Eventually, the two groups would diverge enough to constitute different species, correct?  I assume it would take  too many generations to be practically tested; otherwise someone surely would have tried this already.  Has anyone ever estimated how many generations it would take before the two groups would be considered different species?  Even if they weren't different species, at what point would a measureable genetic change be observable?  Thanks.

Hi Al,

I am sure that several different people on the site will answer this and give very in depth answers, which will be good.  I will give a quick answer that is something I saw in the media last week.  A canadian team looking at birds in North America found that several species of easily recognisable, well known birds, actualy represented more than one species in easch case. 
643 species of birds were catalogued, as known species, but their were 15 new DNA 'signatures' suggesting that separating some of the species into multiple species could be argued for.  It was observed that although the 'different species' look the same to humans they do not interbreed.
It should also be noted that the DNA from several Gull species suggested that the mulitple species could be 'collapsed' into a single species.
The upshot of this, is that it is possible that speciation is going on all around us.  We just don't always recognise it.
A separate study, by another Canadian group, found 8 new species of bat in Guyana, amongst the '87 known species'.  A link to the (Victoria) Times Colonist news paper is below. … mp;k=17112

This doesn't really answer your question, but I hope that you find it interesting.

Last edited by Neil Gostling (1st Mar 2007 12:38:44)