They have succeeded in their goal. None of their constructs have a different activity. They conclude that evolution is disproved.
This may seem a bit illogical, and indeed it is. Nevertheless, Ann Gauger set out to show that her logic is sound in a post entitled "Is Evolution True? Laying Out the Logic." In that post she made up a strawman version of an evolutionary argument. It goes like this ...
Ann Gauger thinks this is a flawed argument because it assumes the very thing that one is attempting to prove; namely, evolution.
- Evolution is true. That is, enzymes have evolved new functions by a process of random mutation and natural selection.
- Modern enzymes can't evolve genuinely new functions by random mutation and natural selection but can only tinker with existing functions.
- Therefore, ancient enzymes must have been different, capable of carrying out a broad range of enzyme activities.
- Those enzymes underwent duplication and diverged from one another, becoming specialized.
- How do we know this happened? Because we now see a broad array of specialized enzymes. Evolution is the explanation.
This begs the question of whether evolution is true. It is a circular argument unsubstantiated by the evidence and unfalsifiable. No one can know what ancient enzymes actually looked like, and whether they really had such broad catalytic specificities.I wanted to discuss the logic of her argument that evolution can't happen so I posted a comment on the same day that her post appeared [A creationist argument against the evolution of new enzymes]. I outlined a more reasonable argument in support of the evolution of two enzymes with different functions from a common promiscuous ancestor. Here's my reasoning ...
Before looking at her version of logic, let me outline the standard evolutionary explanation for the evolution of enzymes with new functions from pre-existing enzymes with different functions.I think you can see the difference between what Ann Gauger wrote and what I wrote. I don't ASSUME that evolution occurs, I state that it is a proven fact. It has been shown repeatedly that the frequencies of alleles in a population change over time and that natural selection and random genetic drift are responsible for those changes.
- Evolution is a proven fact. It can be easily observed in the lab.
- The evidence that evolution has occurred in the past is overwhelming. This is especially true of molecular evolution. It would be perverse to ignore all this evidence and claim that genes have not evolved over billions of years.
- Primitive enzymes were probably promiscuous—they were able to catalyze reactions with a large range of related substrates [The Evolution of Enzymes from Promiscuous Precursors]. Many modern enzymes have broad specificity.
- Homologous enzymes with different, but related, specificities probably evolved from promiscuous ancestral enzymes following a gene duplication event and subsequent specialization of the two copies. Evolution in the two lineages occurs by a combination of natural selection and random genetic drift.
- It's possible to deduce the amino acid sequence of an ancient enzyme from a phylogenetic tree. Some ancient enzymes have been constructed and some of them react with multiple related substrates (promiscuous) as predicted.
- Therefore, it's reasonable to conclude that homologous enzymes with different specificities can evolve from promisuous enzymes in this manner.
I then go on to say that there is overwhelming evidence to support the idea that genes have evolved in the past over a period of billions of years. This is not an assumption. It is supported by scientific evidence.
Given that evolution occurs, I then go on to outline a scenario for the evolution of two related enzymes with different specificities. In several case those predictions have been proven by reconstructing the ancestral enzyme and showing that it can catalyze a broad range of reactions. I've posted one example of duplicated genes caught in the act of diverging [Evolution of a New Enzyme]. In another case, you have the related enzymes lactate dehydrogenase and malate dehydrogenase that catalyze different reactions but you can convert lactate dehydrogenase to malate dehydrogenase by changing only one amino acid [The Evolution of Enzymes from Promiscuous Precursors].
Seems like a pretty sound argument to me.
Ann Gauger doesn't think so: Is Evolution True? Laying Out the Logic, Part 2. Here's why she thinks I am mistaken ...
Moran's statements #1 and #2 amply indicate that he believes evolution is true. The evidence for evolution that Moran says is so overwhelming is no doubt based on how similar things are, on the observation that they can (sometimes, considering some traits) be arranged in hierarchical groupings, and that they have changed over time. I acknowledge those facts. But that does not prove things got that way by a process of random mutation, selection, and drift. That has to be demonstrated.That's a very interesting kind of logic. I assume she accepts the fact that antibiotic resistance can evolve by mutation and natural selection but balks at the idea that this process took place in the past. Even Michael Behe agrees that chloroquine resistance can evolve by mutation and natural selection.
I assume she knows that the genetic differences between humans and chimps are consistent with mutations and fixation of neutral alleles and that this data is roughly consistent with known mutation rates and rates of fixation according to population genetics [Why are the human and chimpanzee/bonobo genomes so similar? ]. I can only imagine how she manages to accept these facts but reject evolution.
Is she really saying that she accepts all the scientific facts but that she has a better explanation that accounts for all the data?
You see? Moran begins by assuming evolution is true, then hypothesizes a mechanism for how enzymes must have evolved, then concludes that his explanation is reasonable. But how much would he accept the story about ancestral proteins being promiscuous if he didn't believe wholeheartedly that enzymes had evolved by the standard evolutionary mechanism? His conclusion is based on his stated assumption.Do the IDiots actually believe this nonsense? Is she really saying that all evolutionary biologists are wrong because their entire field is based on a false assumption and false logic that is patently obvious to Intelligent Design Creationists but not to scientists?
That circularity, you may have noticed, is precisely what I said about evolutionary logic.