Friday, 4 September 2015

Idiotic Antics of the Unintelligent Designer.

Arizona’s virgin ant queens could shed light on the predictability of evolution | Science/AAAS | News

It makes you wonder just how many examples of the sheer stupidity and lack of intelligence in so much of biological 'design' it will take to force creationists to abandon their notion that a magic man intelligently designed everything.

I mean, it's like continually showing them the flat surfaces, sharp edges and corners on a cube to convince them it's not a sphere and have them tell you you're the one with the problem; you're the one who can't recognise a sphere when you see one.

Here's yet another example of stupidity, this time in the evolution of isolated populations of ants (Monomorium emersoni), where the same solution is arrived at in different ways, although, to be fair, there is some commonality due to the limited ways the solution can be achieved. But you can rely on the Unintelligent Designer to find two or more different solutions to the same problem if there are two or more solutions.

10,000 years ago, these ants inhabited an area of meadow and forest in what is now the Arizona, USA. Like most ants, the virgin queens of this species were winged and mated in nuptial flights then dispersed to found new colonies. This ensure a continuous mixing of the genome across the range. Rising above this fertile area were five 2,400 metre high mountains, then a warmer climate turned the lowlands into desert and the mountains into virtual islands of forest surrounded by desert.

Now, whilst it's a distinct advantage to have wings for dispersal in a continuous fertile area, living on islands surrounded by desert makes this distinctly disadvantageous because there are far more ways for a mated queen to find herself in a desert than to find herself on an island of vegetation. So now being wingless was distinctly advantageous so, as would be expected in this situation, the ants evolved to become wingless.

But, as research by Marie-Julie Favé, a biologist at the University of Montreal in Canada, and colleagues has shown, not surprisingly, the five populations have diverged considerably, the way they have evolved flightlessness involves changes in the same genes associated with wing development and flight, but there are differences in the details.

The Arizona Sky Islands. a Satellite image of North America showing the location of the Arizona Sky Islands (yellow box). b A picture taken on a Sky Island from high elevation. Across the desert at the horizon, a second Sky Island can be distinguished. Alternative phenotypes of Monomorium emersoni queens: c winged queen and d wingless queen. e Map of Southeastern Arizona showing the relative location of the five Sky Islands indicating our sampling sites (black dots) and 500m topographic contour lines. f Representation of the highly conserved gene network that controls wing development in Drosophila melanogaster. Arrows indicate activation and bars indicate repression. Genes examined in this study are shown in black.*
Abstract*

Background
A fundamental and enduring problem in evolutionary biology is to understand how populations differentiate in the wild, yet little is known about what role organismal development plays in this process. Organismal development integrates environmental inputs with the action of gene regulatory networks to generate the phenotype. Core developmental gene networks have been highly conserved for millions of years across all animals, and therefore, organismal development may bias variation available for selection to work on. Biased variation may facilitate repeatable phenotypic responses when exposed to similar environmental inputs and ecological changes. To gain a more complete understanding of population differentiation in the wild, we integrated evolutionary developmental biology with population genetics, morphology, paleoecology and ecology. This integration was made possible by studying how populations of the ant species Monomorium emersoni respond to climatic and ecological changes across five ‘Sky Islands’ in Arizona, which are mountain ranges separated by vast ‘seas’ of desert. Sky Islands represent a replicated natural experiment allowing us to determine how repeatable is the response of M. emersoni populations to climate and ecological changes at the phenotypic, developmental, and gene network levels.

Results
We show that a core developmental gene network and its phenotype has kept pace with ecological and climate change on each Sky Island over the last ∼90,000 years before present (BP). This response has produced two types of evolutionary change within an ant species: one type is unpredictable and contingent on the pattern of isolation of Sky lsland populations by climate warming, resulting in slight changes in gene expression, organ growth, and morphology. The other type is predictable and deterministic, resulting in the repeated evolution of a novel wingless queen phenotype and its underlying gene network in response to habitat changes induced by climate warming.

Conclusion
Our findings reveal dynamics of developmental gene network evolution in wild populations. This holds important implications: (1) for understanding how phenotypic novelty is generated in the wild; (2) for providing a possible bridge between micro- and macroevolution; and (3) for understanding how development mediates the response of organisms to past, and potentially, future climate change.



The authors were actually trying to resolve the debate amongst evolutionary biologists over whether evolution is predictable, in other words, if we could re-run it, would it produce the same results again, or is there too much randomness in the process? What this study shows is that, where the opportunities are limited (there are only so many genes involved in making wings) and the selection pressure is highly directional (in this case flightlessness was almost an imperative if a huge attrition in queens was to be avoided), the outcome can be predictable, however, the precise mechanism can vary.

In my humble opinion, this hasn't really answered the question, but the implications of variance even where the options are so limited and the advantageous outcome is clear, suggests a great deal of randomness, so a re-run of evolution is far less likely to produce the same results again than to follow the same path exactly. The longer the period and the lower the strength of the environmental selectors, the more the re-runs will tend to diverge.

But, the interesting question for the unfortunate dupes of the Intelligent (sic) Design hoax to answer is why there were these small differences. Having blundered in making the climate change to produce the hostile desert surrounding these isolated 'islands' of vegetation, and so creating the need to change these ants to avoid them becoming extinct in the first place, why did this supposed 'Intelligent (sic) Designer' come up with five slightly different ways to do the same thing, almost exactly as though it were five different designers who didn't talk to one another?

Any offers, or is to be the blind eye, deaf ear, and denialism yet again?


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2 comments :

  1. Hi Rosa, I referenced this blog post, and several other posts of yours, in my Blasphemy Rant, announced on Google+ today, in celebration of Blasphemy Rights Day.

    http://blasphemy-rant.blogspot.com/

    ReplyDelete

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