RAPPING EVOLUTION, WITH STAN

Stan sums up his feelings regarding the theory of evolution by natural selection (TENS, for short):

First, evolution resulting in speciation requires mutation; possibly introgression; and sexual selection. I am now able quote sources on this.

I'd like to see them. As far as I can see, there's absolutely no requirement for sexual selection. Asexual populations evolve as well. And, I think Stan's too hung up on mutations, especially in terms of their randomness. Mutations happen constantly, whether the populations in question speciate, or no. You might say it is a built-in feature of living things. One could just as well say that 'evolution resulting in speciation requires reproduction.'

Second, I am still unaware of real examples of true speciation, with the single possible exception of ring species, which I still have under study. I am not convinced that the species ever really were the same identical creature; that is not empirically provable. It appears to be another extrapolation of fortuitous circumstances, ie, circumstantial evidence.

The classic unlooked-for case of incipient speciation was stumbled upon, quite by accident, by Dobzhansky's group in the late 1950's and spawned a fascinating series of articles, many of which are available at the PNAS archives. The Drosophila literature is filled with this stuff, but what makes the Llanos B strain of D. paulistorium so intriguing is that it appears to be sympatric with other populations. It's been suggested that somewhere between the Orinoco basin and the lab that some of the flies got 'jet lag', and habitually bred later than other varieties whose internal clocks were less brittle. These flies were effectively separated from other flies with which they might have interbred in the wild.

Whether or not a mutation was instrumental was not actually determined in the initial research, though I should confess for Stan's benefit that I am certain that mutations occurred both before and after the speciation event. For me, bottom line, there are other mechanisms besides point mutations which, when coupled with some form of isolation, can lead to speciation. Stan, I would encourage you to go to the PNAS site and just search under 'Drosophila paulistorium' or 'Dobzhansky' and enjoy the reads. They are surprisingly accessible, tokens of an earlier time in biology before the molecular revolution had hit its stride.

And, for a very specific and recent instance of Drosophila sp. undergoing speciation in the wild, check out this article. It's part of a burgeoning literature on in situ evolution in various taxa from a model site in Israel that's been christened 'Evolution Canyon', whose usefulness can be seen in this graphic, from Johannes Sikorski's home page:



If the usefulness of this location doesn't immediately suggest itself, Sikorski has a very thorough explanation on his site which I commend to everyone.

ATHEISM'S JAY LENO?

Some may recall that early on his Tonight Show career, talk show host Jay Leno was not above a covert operation:

Jay Leno has admitted that soon after he debuted as host of the Tonight show, he was so worried about negative critical and audience reaction -- and about being replaced -- that he hid in the closets of NBC executives so that he could eavesdrop on their conversations about him.

Now, low and behold, Science Blogger and All-Around Evil Atheist Conspirator PZ Myers has pulled a similar stunt. The gall! The chutzpah! The envy that I'm feeling!

Separated at birth?

(Be warned: the comments are a bit hot and heavy. I probably should've distinguished between Dr. Myers's opportunity to be a 'fly on the wall'---which I did envy----and the way he reacted. But, as I see it, I might have well reacted the same way under the circumstances. We're all capable of being provoked,and I certainly provoked some commenters, sad to say)

MILESTONES

This is my 300th post since beginning this blog about 11 months ago. I've somehow managed to average a post a day. Not that big a deal when compared to the profligacy of some, but something of a surprise to me. I never imagined I would end up posting so often.

Also, I've had about 8,000 visitors in the last 72 hours, largely due to my glomming onto the hubbub about 'Expelled.' I hope most of my visitors found what I had to share helpful or interesting, and it tickles me to get that amount of traffic. Again, a surprise to me, and again a definite milestone.

I would like to thank two people, especially, for encouraging me to start blogging on my own. One is my friend and colleague Madhusudan Khatti. The other is my friend Calladus of CVASS. Thanks, gentlemen. You were right, and I'm glad that I listened to your advice.