Thursday, December 19, 2013

"Evolutionist" - A Reddit debate

I apologize for the scarcity of news articles this week; news relating to origins has been slow lately.  In the meantime, I have been involved in a debate on Reddit about the validity of the term "evolutionist" and the supposed proofs of evolution.  The thread can be found here, but I will post a copy in case you are unfamiliar with the site:

[Original post by a former creationist (user we_are_sex_bobomb) about becoming an evolutionist] 
PurpleSharkS***:
I really don't like that word. Being an "evolutionist" shouldn't be a thing, it implies that evolution is a belief. It's just a thing that happens. I wouldn't call myself a radiationist or an eatist or a toasterist. Radiation, eating, toasters, and evolution all exist and can be proven to exist. Calling yourself an evolutionist validates YEC by implying that evolution is a belief, and not a reality. Okay, I'll get off my soapbox now. Good for you, and I'm glad things went well with your family. Love is certainly stronger than opinion. 

HonestCreationist:
I normally use the term "evolutionist" to refer to someone who relies on evolution to explain current biodiversity, not necessarily someone who simply believes in evolution. Likewise, if I was involved in a debate over whether toasters or toaster ovens are more effective in making toast, I would call one side "toasterists" and the other side "ovenists." The "-ist" ending does not imply belief, but support. 

intravenus_de_milo: 
"evolutionist" to refer to someone who relies on evolution to explain current biodiversity, not necessarily someone who simply believes in evolution. 
I'm probably going to regret asking, but what is this supposed to mean exactly? I know some creationists maintain that there have been several creation "episodes" that account for biodiversity repeatedly through Earth's history, from the Cambrian explosion to the KT event, to the PT even and so forth , but let's not conflate that with evolution at all. Evolution is not something that can exist within "punctuated creationism." If you want to be an "honest creationist," don't go co-opting the term evolution to describe something it's not. 

HonestCreationist:
Ultimately, it depends on the definition of "evolution," as you alluded to. For example, I believe in evolution when it is defined as a shift in gene frequencies within a population, frequently expressed as phenotypic changes in response to environmental pressures. I think it is a scientifically observable fact. However, I don't think that all life is related by evolution. Some, but not all. I think that discrete kinds of life were created by God (about 6000 years ago, but the timing is irrelevant in this discussion), and that those kinds underwent evolution to produce the diversity of life we see today. Because I refer to special creation to account for the majority of biodiversity, I am a creationist. Someone who explains the majority or entirety of biodiversity with evolution would be called an evolutionist, even though we both accept evolution as fact. It is not the validity of the theory, but the application that determines the label. 

intravenus_de_milo: 
However, I don't think that all life is related by evolution. 
Well, the evidence is overwhelmingly pointing in that direction. If life was created independently, they should look independent don't you think? Yet we share something like 50% of our genome with bananas. And indeed if you overlay genetic similarity over taxonomical similarity over the fossil record, you have a very convincing portrait of common descent -- as you can arrive at the same "tree" three totally different ways. Consider taxonomical categorization predates Darwin, and yet when you look at the cutting edge of modern genetics, you get the same branches. You can deny it, but there's no sound scientific nor theological reason for some convoluted view of creation. 

HonestCreationist: 
Well, the evidence is overwhelmingly pointing in that direction. 
That's beside the point. Regardless of the truth, some people believe in evolution and use it to describe all biodiversity, and some people don't. 
If life was created independently, they should look independent don't you think? 
Not necessarily. I have a hard time distinguishing some cars made by independent companies. 
Yet we share something like 50% of our genome with bananas. 
If that is indeed true, it just goes to show that genetic similarity isn't very indicative of close relationships. 
And indeed if you overlay genetic similarity over taxonomical similarity over the fossil record, you have a very convincing portrait of common descent -- as you can arrive at the same "tree" three totally different ways. 
I've heard this claim many times, but I have yet to see evidence for it. Do you have any sources that compile three independent trees using these methods? 
Consider taxonomical categorization predates Darwin, and yet when you look at the cutting edge of modern genetics, you get the same branches. 
Do you think taxonomic groupings remained unchanged since Darwin's time? 
You can deny it, but there's no sound scientific nor theological reason for some convoluted view of creation.
I agree. We apparently just disagree on which view is "convoluted."   
schwuppdiwupp: 
 Yet we share something like 50% of our genome with bananas. 
If that is indeed true, it just goes to show that genetic similarity isn't very indicative of close relationships.
Except that as you look at more and more similar species, that number rises.
A banana and a human being significantly genetically similar is simply evidence for relation. However, the fact that a lizard is more genetically similar to a human than the banana, and a dog is even more similar, and a chimp is even more similar, goes to show that genetic similarity is indicative of close relationships.  

HonestCreationist: Isn't genetic similarity used to determine these relationships though? Saying, then, that there is a correlation between genetic similarity and evolutionary relationship is meaningless.  
schwuppdiwupp: Nope. This is what /u/intravenus_de_milo means when he talks about overlaying genetic similarity with taxonomical similarity. Methods exist to classify organisms based on morphological similarity, for example. When you compare these relationships with those determined by genetic similarity, there is a high degree of correlation. 

HonestCreationist: So I ask again, is there a source for this "high degree of correlation?" 

schwuppdiwupp: 
I'm pretty sure this is where I remember reading about it (section 1.3). 

HonestCreationist: I'll give you credit, that's probably the best one I've been shown, but I still see some problems.
  • It is claimed that the morphologic and genetic trees match with a "high degree of statistical significance," but the author later notes that such a degree of significance can be achieved even if 10 of 16 branches did not match. Therefore, I can't say I'm impressed by statistical significance.
  • As the author mentions, analysis of a single gene is not particularly rigorous, whereas congruence demonstrated with multiple genes would be much more convincing. Multiple studies are then cited:
  1. Baldauf et al. 2000: Curiously, the link to the full text appears to be broken, but the title and abstract indicate that that this is a kingdom-level phylogeny, which is hardly specific. I am not surprised that genetics would reflect the claimed evolutionary relationships on such a large scale. Rather, the smaller-scale branches are where it appears to break down. Furthermore, the abstract says that the protein-based phylogeny has "striking differences" from the rRNA phylogeny, implying an incongruence between the molecular data itself, let alone between molecular and morphological data.
  2. Hedges 1994: I am not sure why the author cited this article. While it does involve analysis of multiple genes, the abstract and introduction clearly state that the molecular data does not support the morphological data.
  3. Hedges and Poling 1999: As above, the abstract shows that molecular analysis defies the classical morphological phylogeny, and adds that "morphological and paleontological evidence for this molecular phylogeny is unclear."
  4. Penny et al. 1982: This study does not compare molecular data to morphological data, but it compares 5 different proteins to each other. Only 11 species were used, but I cannot access enough of the article to see which 11 species these were. I also can't see how well the trees matched, as the authors only state that their "results are consistent with the theory of evolution."
  • Most of the sources cited are pre-2000, before genome sequencing of different species was really underway. They rely more on sequences of amino acids than on actual genetic data, which do not necessarily correlate, as placement of genes and structure of introns and exons can vary widely.

schwuppdiwupp: 
It is claimed that the morphologic and genetic trees match with a "high degree of statistical significance," but the author later notes that such a degree of significance can be achieved even if 10 of 16 branches did not match. Therefore, I can't say I'm impressed by statistical significance.
I agree that that doesnt sound very impressive on its own. But in light of this quote: 
Biologists seem to seek the 'The One Tree' and appear not to be satisfied by a range of options. However, there is no logical difficulty in having a range of trees. There are 34,459,425 possible [unrooted] trees for 11 taxa (Penny et al. 1982), and to reduce this to the order of 10-50 trees is analogous to an accuracy of measurement of approximately one part in 106.
- (Penny and Hendy 1986, p. 414) It sounds much more significant. Plus, the author goes on to say: 
For a more realistic universal phylogenetic tree with dozens of taxa including all known phyla, the accuracy is better by many orders of magnitude. 
the standard phylogenetic tree is known to 38 decimal places, which is a much greater precision than that of even the most well-determined physical constants. 
the relationships given in Figure 1, as determined from morphological characters, are completely congruent with the relationships determined independently from cytochrome c molecular studies
The tree in question, consisting of 30 taxa I might try to find some more recent papers later, but for now but I have some Christmas shopping to do. Have a good one!

I am waiting to see if schwuppdiwupp comes up with any more evidence or rebuttals.  In the meantime, I did some more research on the study in question and found that several studies of the cytochrome c protein place animals in strange places in the tree of life, such as putting turtles as more closely related to birds than any other reptiles, and placing kangaroos after the split of monkeys from other mammals.  Finding more recent studies has been difficult, likely because the field of genetics is focusing on sequencing genomes before any comparisons can be made.

As usual, if you have any questions, feel free to leave them in the comments or send an email to admin@honestcreationist.com!


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