January 21, 2007 - January 27, 2007 Archives
Yesterday’s post on evolutionary speed limits and Haldane’s Dilemma has sparked some interesting discussion, and some of the comments have already started to move beyond the very simple scenario that I outlined. Next week, I’ll post a couple of more complex examples, and look at the effect of things like a lower frequency of mutants in the starting population, what can happen with two mutations being selected at the same time, and whether mutations need to be fixed to be evolutionarily meaningful. I’ll also go over a couple of basic concepts that might help in understanding those scenarios.
Today, I’m just going to respond to part of one of the comments that was left on the last post. This is mostly because it’s an interesting question that deserves a thorough response, partly because the question involves some basic concepts that should be explained before I dive into more detail, and partly because it’s Friday and I really don’t want to spend the time plugging numbers in to work up another example.
Caligula, fairly early on in the comments, raises a point that involves a concept that is very basic to evolutionary biology: fitness:
There’s been a bit of talk about “Evolutionary Speed Limits” over at the Intelligent Design weblog Uncommon Descent. Most of the discussion involves “Haldane’s Dilemma.” This concept is rooted in an article written by the noted evolutionary geneticist J. B. S Haldane in 1957. There’s a lot of math involved, and you can see it over at the Wikipedia page I linked above. The bottom line, for those not interested in the math, is this: according to Haldane’s calculations, a species cannot reasonably fix beneficial mutations (a particular mutation becomes “fixed” when it is present in all of the population) at a rate any faster than 1 mutation per 300 generations.
A number of anti-evolutionists have taken this as evidence against evolution. If, they argue, genetic changes can only be fixed at a rate of 1 per 300 generations, how can evolution possibly explain the differences between species like humans and chimps, where not nearly enough generations have passed to account for the number of differences that we observe. There are a number of problems with using Haldane’s calculations in this way, and in this post I’m going to look at one of those - the one that I think is the most important. For clarity, I should probably make sure that I am very explicit about what, exactly, the problem is before I start, so here it is:
Using Haldane’s 1 substitution per 300 generations as a speed limit for all evolution is wrong because Haldane’s calculations and concerns only apply under certain very specific circumstances.
Yesterday, I pointed out that Jonathan Wells was grossly ignorant of basic ideas in evo-devo. This isn't too surprising; he's a creationist, he has an agenda to destroy evolutionary biology, and he's going to rail against evolution…same ol', same ol'. That's nothing, though. Wells and his fellows at the Discovery Institute have an even more radical goal of fighting natural, material explanations of many other phenomena, and his latest screed at the DI house organ is against natural explanations of development. Not evolution, not evo-devo, just plain basic developmental biology—apparently, he wants to imply that the development of the embryo requires the intervention of a Designer, or as he refers to that busy being in this essay, a postmaster.
PZ reports on Wells: Jonathan Wells knows nothing about development, part I
If one were asked who the very worst advocate for Intelligent Design creationism was, it would be a difficult decision—there are so many choices! Should we go back to first principles and pick PJ Johnson, the cunning lawyer who has the goal of undermining all of science? Smarmy and obtuse Sal Cordova? Pompous and vacuous William Dembski? I’m afraid my personal most loathed ID creationist has got to be Jonathan Wells.
The reason? The man claims to be a developmental biologist, my favorite field of science, and actually has some credentials in the discipline…but every time he speaks out on the subject, he stuns me with his ignorance. Here he is, trying to explain the Cambrian explosion.
Read the rest of the story at Pharyngula
Note that this is part I, apparently Jonathan Wells has written an even more outrageous claim.
The NCSE reports on an Antievolution bill in Mississippi
Mississippi’s House Bill 625, introduced by Representative Mike Lott (R-District 104) on January 9, 2007, and referred to the House Committee on Education, would provide, if enacted, “The school board of a school district may allow the teaching of creationism or intelligent design in the schools within the district. However, if the theory of evolution is required to be taught as part of the school district’s science curriculum, in order to provide students with a comprehensive education in science, the school board also must include the teaching of creationism or intelligent design in the science curriculum.” A similar provision was part of 2005’s House Bill 953, of which Lott was the chief sponsor; HB 953 died in committee on January 31, 2006.
Comment: Seems that the faithful have not gotten the Discovery Institute’s memo. However, the link between ID and creationism seems undeniable once again.
The East African Standard has a new (well, a week and a half old, but new to me) article concerning the attempts by evangelicals to suppress the hominid fossils currently on display in Kenya’s National Museum. You may remember when this ruckus first began several months ago. We now learn that churches are planning on holding “major demonstrations to the museum to press for the removal of the bones.”
On UncommonDescent, GilDodgen quotes from Denyse’s comments
GilDodgen Wrote:Denyse Wrote:
Bear with a simple lay hack here a moment: Why must we know a designer’s intentions in order to detect design?
If the fire marshall’s office suspects arson, do the investigators worry much about WHY?
Surely they investigate, confirm their finding, and turn the information over to other authorities and interested parties, without having the least idea why someone torched the joint.
ALL they need to be sure of is that the joint did not torch itself, via natural causes.
The observation Denyse makes is so obvious that one would need a Ph.D. in obfuscation not to see it. Common sense is not so common, at least among those with a foundational commitment to materialism.
Gil is right, Denyse’s observation is so obvious and wrong. Of course, in order for this to understand, it requires one to shed the veil of ignorance and determine how design is detected in real life and furthermore how intelligent design wants to detect “Design”. Note that I am distinguishing between design and Design to avoid the equivocation so commonly found in ID literature, leading to much confusion amongst its followers.
On Pandasthumb, our dear friend Salvador Cordova (YEC) presents us with the following “argument”
Pellionisz FractoGene has demonstrated at least one layer of linguistic architecture for the junk DNA. A linguistic structure suggest function even if the structure is not fully understood (like seeing an undecoded communication, the communication has function, but it is not understood). Furthermore, Fracis Collins called it hubris to say any part of the genome is junk.
Salvador may perhaps not be familiar with the term ‘non-coding DNA’ which describes much better the scientific thinking on the somewhat unfortunate term “junk DNA”, especially since the term seems to be used for cherry picking rhetoric. In this posting I will explore the term junk DNA, address some of the findings in research that DNA and junk DNA show “linguistic features” and show why ID remains fully vacuous since it cannot predict let alone explain “junk DNA”.