Speciation accidental

Just saw this in the New Scientist...
http://www.newscientist.com/article/mg20527511.400-accidental-origins-where-species-come-from.html

Mark Pagel shows that speciation occurs at a random rate not something you would expect if it required the accumulation of genetic errors and selection. Obviously random events like geological or climate changes would effect speciation but whole trees exhibit this character of exponentially reducing length of non-speciation e.g. 1/5, 1/5*1/5, 1/5*1/5*1/5, 5^-4, 5^-5 ... (if probability of speciation is 1/5).

Now this strikes me as correct. The forms that we see in nature are a combination of developmental restraints (symmetry) , adaptation (evolution of water-tight coverings) and accident (why are female peacocks like big tail displays?)

Just looking at some excellent VRML models of insects yesterday really showed up the extraordinary shape of nature... and also its arbitrariness. Why did this help consider the problem? In VRML the possibilities are infinite save only the creativity of the modeller. Thus when the modeller copies natural forms they are inadvertently copying shapes that have hidden causes. A butterfly is a very complex form - with a long, long, long genetic history and unnumerable physical, chemical, biological restraints: none of which are present in a VRML environment. The only restraint in that environment is physical consistency so that for example a keg cannot spiral around through the body. The shape that is being copied is the product of an as yet incompletely defined function: life. It makes it more vivid how undefined it is when we see the modeller having to apply his skills to all those legs and hairs and joints without necessarily understanding why this is this and that is that.

Does it "have" to look like this is the question? What would aliens look like given the same raw physical environment, but a different family tree and random events?

here also...

http://scienceblogs.com/evolvingthoughts/2007/03/evolution_and_accident.php