Revenge of the cichlids:
I used to feel quite smug about cichlids. They were little candy coated bits of chewing gum named after the chicle that makes them chewy. Life became more complicated when it turned out that was Chiclets. Cichlids were fish found notably in Lake Victoria in Africa. That lake, memory serves for a change, is about the size of Ireland. What was remarkable was that there were about 500 kinds of fish, mostly cichlids all these different species living close together. Then it turns out that Lake Malawi, about the length of the Nile valley from Luxor to Cairo and three times as wide, has a like number. So people wondered, and still wonder, how it happened.
I even had a friend who had some Lake Victoria cichlids in his fish tank, explaining that they were very popular.
Then there was a problem. Agriculture grew up around Lake Victoria. The fish had been sorting their mating by color, but in the murky water they couldn’t tell one color from the next. That meant that locally, the gene pool enlarged to an extent the fish had not adapted to, and they were going extinct. The learned boffins decided it was because predators had been introduced. Everybody, save me and thee, knows that diversity is always wonderful.
Well, there’s this other lake. (Milan Malinski et al. Genomic Islands of Speciation separate cichlid ecomorphs in and East African Crater Lake Science vol. 350 no. 6267 Decmber 18, 2015 page 1493) It’s like a half dozen football fields worth, Lake Massoko. There are only two species, so it’s a lot easier to figure out what is related to which.
Cichlids, by the way, are widely present throughout Africa.
They have done whole genome studies on these two kinds of fish and related them to physical and behavioral difference.
Thus the study of speciation proceeds. My hunch is that all forms tend to undergo speciation somewhere around 2,000 generations. I suspect that it will be a long time before science comes up with the right number.
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