Thanks for the warm welcome. I’m still reading through the book in my free time. I’ll write down any questions I have along the way. Also, I look forward to your next apperance on Capturing Christianity.
You said, “That formula + common ancestry predicts a large range of patterns in DNA. Common ancestry is important because it means that all the clocks have the same starting point in the past. That is why scientists think common ancestry is true. To reject it we would need to see a mathematical theory of equivalent rigor that makes predictions this well or better.”
First, so what I understand is that because when we assume common ancestry one can predict DNA patterns, thus common ancestry is viable, is that correct? What exactly do you mean by “a large range of patterns”?
Second, do I understand you to mean by “That formula + common ancestry” that if you assume the difference between two creatures being compared is accounted for by the observed rate of mutation, then the time of divergence was distance/rate = time? This could conceivably be done with creatures that do not have the same parentage and you still get an answer. That would suggest that your assumption determines your answer. Or do you maybe mean that the morphological chronology (found in fossils) and the DNA based time confirm one another?
-Here is my train of thought for correction. As it relates to molecular clocks. Are these clocks not calibrated by observing the mutations? I assume this is most effective with tiny creatures with quick life cycles and reproduction rates. However, for calibrating based on creatures that evolve more slowly, observing mutation is not an observable process except in a historical sense. (Am I wrong?) This seems to me to be problematic. I imagine calibration for these creatures is based on the fossil record, which is likely dated based on morphology patterns. Dates are approximate or even pliable to some degree. This seems to me to be self-fulfilling.
Also, are the dates for fossils not also dated in the same manner? If so, this is what I think confuses me. It seems as if the mutation rate, is based on a sample of mutation over time, and for more slowly evolving creatures this is determined by the fossil record (by nodes or tips). In such a case, the dates of the fossils help determine the rate of change, and these dates may be determined by that rate of change. That is self-fulfilling: The date determines the rate of mutation and hence that rate confirms that same date and vice versa. This is obviously circular. I’m confused.
In addition to that, it occurs to me that by choosing what you are comparing (in DNA or morphology) to determine distance you could conceivably, choose data that matches what you are looking for. You can prove whatever you want in this manner. This is something done in statistics sometimes. I conclude that I must be missing something.
" Common ancestry is important because…scientists think common ancestry is true."
Yes, but what I think you mean logically sounds circular to me. I’m having trouble understanding it.
“To reject it we would need to see a mathematical theory of equivalent rigor that makes predictions this well or better.”
So, do you mean to say that this formula represents accurately what we find in the fossil record, and/or predicts accurately the projection of evolution? (Future or past predictions?) It certainly seems less complex to assume common descent. However, it seems feasible, off the cuff, that one could come up with a new form of the theory to account for diversity. Like I said, I’m not sure what kinds of predictions you are referring to.
In light of the fact things evolve similarly yet separately like seals and sea lions, what if there were primordial oozes rather than just one? Or imagine if single celled life forms piggy backed on a meteorite and landed on earth and began evolving alongside life on earth for billions of years how might we distinguish them?
“I am familiar with the claim but unfamiliar with evidence supporting it.”
Regarding examples of genetic limitations: So, “since we know the number of alleles in the genetic code is limited and the natural variation that occurs as a part of reproduction is limited, therefore the variation a species can experience is not unlimited. It is limited by the number and type of alleles in the species genetic code…( if) a life form has unlimited ability to change it means that some process must exist to add information. There are only a certain number of genes and alleles of those genes there is therefore only a certain number of possible variations in genotype, and therefore a limited number of phenotypes.”-Wiles and Durnell
Different criteria give different relations, so if you look at one particular point in the code you might get a different looking evolutionary tree. For example, there are different ways of making an amino acid- case and point, Cytochrome C production. “Certain proteins are common to many species like cytochrome C, but each individual species has its own sequence to make cytochrome C. The cytochrome C that is in a bacterium is sequenced a bit different from the one in a human. The sequence is a little different for each species. One would assume the process of evolution would show that the sequences with the least amount of differences would be the species that are more closely related. Most of the time this is not the case” -paraphrase of pg 285 of Exploring Creation with Biology by Wiles and Durnell.
Other questions I had while reading:
As I understand it so far, ubiquitous genes are genes in common between all life forms. Do ubiquitous genes make making an evolutionary tree based off DNA easier or more difficult? What I mean to say is if everything is related, how do you know what gave rise to what?
Would you personally describe evolution as a random process? If so, what do you mean by random?
Can the evolutionary tree not be reformed based on different criteria? How can there be consensus then?
Why don’t we see other evolutionary processes popping up on earth from a different (molecular) composition?
Is it feasible to make DNA using different polymers and make a different kind of life?
How can you even compare DNAs with different numbers of chromosomes? For example crawdads have 200 and people have 46.