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Good TV show

MonteSS

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Sci-fi channel. Mutant Planet-Africas Rift valley lakes

I'm watching now but looks like it replays at 10pm tonight. (monday}
 

neut

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I've seen the episode a few times. Underwater footage was nice but the problem I had was with the science. Basically, as sometimes happens, what was presented was only the theory favored by the particular scientist(s) consulted for the program or interviewed on camera-- or the theory known to or favored by the program producers-- the program saying 'this is the story of African cichlids', as though what was presented was confirmed and established fact, or at least currently agreed upon by the scientific community.

As I remember it, the theory presented in the program was that some millions of years ago several lineages of cichlids entered Lake Tanganyika from surrounding rivers, and from there they colonized Lake Malawi, Lake Victoria, and other regional (and smaller) lakes. However, just as scientists debate whether Tyrannosaurus Rex was a hunter or scavenger, this scenario regarding African cichlids is debated within the scientific community (it's the same with the more fundamental major theories regarding the age, origin, and worldwide dispersal of cichlids as a whole, there is not a single confirmed and proven theory, there's more than one theory, each with its own difficulties). A virtually opposite and “widely accepted” theory is that the currently existing lineages of east African cichlids originated or developed within Lake Tanganyika and from there colonized both surrounding lakes and rivers.

By contrast with the Mutant Planet program, some scientific papers are equally confident in stating this opposing theory...
Nature
Evolutionary Biology: Cichlid species flocks of the past and present
More modern haplochromine lineages, some of which also live in the rivers of eastern Africa, derive their origin from the endemic Tropheini of Lake Tanganyika (Salzburger et al, 2005), and some of those were the seeds for the lineages that now form the exceedingly diverse species flocks of Lakes Malawi and Victoria.

While other sources that favor one theory at least acknowledge there's another prominent theory and use more cautious wording, along the lines of 'this suggests' rather than being so dogmatic:
Oxford Journals
Age of Cichlids: New Dates for Ancient Lake Fish Radiations
These calibrations also suggest Lake Tanganyika was colonized independently by the major radiating cichlid tribes that then began to accumulate genetic diversity thereafter. These results contrast with the widely accepted theory that diversification into major lineages took place within the Tanganyika basin.

But, there's a problem with the theory favored by this last reference:
As noted on page 15 of the book “Patterns and Processes of Speciation in Ancient Lakes” Proceedings of the Fourth Symposium on Speciation in Ancient Lakes, Berlin, Germany, September 4-8, 2006 (ISBN reference: 9789048181629)
...the absence of ancient lamprologines and ectodines outside Lake Tanganyika remains unexplained. Although a number of lamprologine species are found in the Congo system and one species in the Malagarazi River, the split of these species from their sister lineages in Lake Tanganyika is, regardless of the calibration used, too recent for them to represent the remnants of an originally riverine species assemblage (Koblmuller et al unpublished data), suggesting that lamprologines secondarily colonized the river systems from Lake Tanganyika...
In other words, in the case of the Lamprologine lineage, making up 40% of Lake Tanganyika species, as well as the Ectodine lineage, evidence of these colonizing the lake from surrounding waters is lacking or problematic. Instead it appears that these fish originated in the lake and from there some of them moved into surrounding waters-- opposite the theory presented in the Mutant Planet program.

Bottom line, whichever theory makes most sense to you, the theory presented in Mutant Planet is not the 'story' or the theory. It's one of the theories being considered, not something that's has been conclusively proven. Might seem nit-picky, but with my interest in science it bugs me when I see science programs that are not objective or that present an incomplete or misleading picture of the actual science by offering only one side of the story or by implying scientific confirmation and consensus where there is actually scientific debate. I'd like to expect more from a science program, but in the end you can't believe everything you see on TV, even on some science programs.
 
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