Help Me Understand

[TheRocketSurgeon]

Bumping this because I think all of you would do well to check out those two links I grabbed, above, especially the PDF of the bone and embryological homologies.

[loganonekenobi]

I too have seen some of the scientific debate vrs evolution. What i take from it is this ... science doesn't know everything and probably never will. That's okay. Science is an ever changing entity just like life. The scientists in this field can and always should challenge their theories and build up on them.

The contention comes when the literalists come thumping their book and say "quit looking we don't need anymore answers." and for a long time they did. Back then the evolutionist was considered the retard but now the creationist is. There is no constant except change.

I say throw the theory of evolution on the fire of scrutiny now and always...not to throw it away but to improve on it.

Science has the power to admit when it is wrong and change... religion...not so much.

[RoadRunner79]

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Sorry for the delayed response.  I have been meaning to get back to this thread, and have been side tracked.  I have not read "The Origin of the Species" (I have downloaded it, and would like to, but since the theory has changed much since, it's hasn't been a priority).
First, the comment on extinct species being found alive and kicking, wasn't an argument against common descent, just that I find it interesting, and is evidence that the fossil record has large gaps by nature.  As I had said I do consider myself skeptical in regards to common descent, and consistent with that I'm not really make claims against it.  
As to evolving upwards or towards something, I have seen studies which may indicate that this may be the case.  I'm going to try and find some links, as my current search didn't produce the results I was looking for.
I am familiar with the tree or bush comparisons to evolution.  However the part that I question is the branches.  I do not see these in the fossil record.  

Part of the reason, that I did take a while to respond is; because I was re-researching Tiktaalik Rosea.  It does seem that this is no longer believed to be a common ancestor to tetrapod’s, but a relation (according to some evolutionist).  There is also a claim of tetrapod tracks prior to Tiktaalik Rosea.  However when searching for walking fish, it seems that there where a number of animals found in the fossil record which share some traits with tetrapods, but they are all different features.  Science shows that the hox gene for tetrapod development of hands and feet are present in paddlefish.  

There are gaps in the fossil record, and I don’t see the connection made in the fossil record.  It is more of this feature in an animal is similar to this feature in another, and it is assumed that common descent is the cause (I don’t think this has been shown).  I would love to see a chart that shows common descent similar to the tetrapod features I found in fish. Something similar to this graph I found on walking fish, but showing more of a progression towards the claims of common descent.  https://en.wikipedia.org/wiki/Walking_fish
I also question some of the claims of broad speciation made from the fossil record.   And in the context of this discussion, I don’t think that the definition of speciation in regards to reproduction is adequate.  

A large problem I believe is that I do not believe that similar features necessitates common descent, and I have not seen the evidence presented in a way which connects the dots across the timeline.  In regards to Tiktaalik Rosea, I had seen on image, in which the fin of a whale was remarkably similar (or more so) than the link to tetrapod's.

No problem. I think you still have a mild misunderstanding of what the implications are, when you say "the gene exists in fish", since it's not really the comparison of the features that makes species related in the evolutionary sense, but common gene-pools which differentiated. Whether they look similar is, as you noted, a side-effect of those genetics, and hox genes (also noted) can make things appear to vary quite rapidly, when selection gets hold of them. A better way to look at the "related features" thing, in terms of common descent, is to ask how that feature came to be a feature of that population-- in other words, "did it inherit the DNA for that feature from an ancestor, perhaps one who used the DNA in a different way or perhaps one who had the same set of features, modifying that feature as the population of the descendant species continued to evolve in its environment?"

Similar features does not  indicate common descent... you are quite correct. BUT, and this is an important qualifier, when we find features of similarity, we must ask whether or not that is the result of common descent or simply a coincidence.  As with the eyes of octopi versus those of vertebrates, we note that while the features are highly similar (called convergent evolution, as you know; there are notable differences in basic architecture and genetics to form that architecture, which allow us to make that distinction). 

I do actually recommend that you read that link; it will give you a good idea of the degree of analysis that such convergence claims undergo, which (respectfully) I think you are too-lightly brushing off.

Also, I cannot stress enough how important Neil Shubin's book Your Inner Fish  is for understanding much of the topic you're bringing up. You might be shocked to learn how much of our body-plan genetics goes clear back to those myriad ancestors, and how our plan-form was selected for and modified over millions of generations. Please, if you want to have an in-depth discussion of developmental genetics and its import for describing/understanding the Common Descent model, nothing would please me more. I often strive to use "common language" in here instead of slipping into technical-speak, but I'd relish the opportunity to speak on a more detailed level about it but if and only if  I can feel confident that I won't waste half the conversational effort on filling in "basic" (to me) knowledge which would prevent misconceptions before and misdirection within the discussion.

You should also check out this PDF series of graphics from the book, via the Tiktaalik website at University of Chicago's website:

http://tiktaalik.uchicago.edu/downloads/...re.ppt.pdf

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TRS,


Thank you for the links.  I have seen similar things before, and did I mention, that I hate drawings presented as evidence.  It does seem to be more of the same.  When similar things are found, and they agree with the common descent model, it shows evolution.  When similar things appear, and they do not agree with the common descent model, then it shows evolution.  I do understand that this is not an inconsistency as there are other factors in the making of the determination, however for one who is skeptical of common descent; I think the second claim takes away from the first.  I also do not think it has been demonstrated, that because these ridges which turn into gills in one embryo look like these ridges which become something completely different in humans and other mammals is evidence of common descent.  It may fit with the story, but similarity as we have seen, does not show common descent necessarily.  Also in the early stages of embryo development, considering what you are going from, to what the end result is, I think it is reasonable to expect a great number of things, to have a similar appearance at certain points.   The fact is that in humans, these are never gills, and do not have anything more than a similar appearance at a certain stage of development.

[TheRocketSurgeon]

TRS,


Thank you for the links.  I have seen similar things before, and did I mention, that I hate drawings presented as evidence.  It does seem to be more of the same.  When similar things are found, and they agree with the common descent model, it shows evolution.  When similar things appear, and they do not agree with the common descent model, then it shows evolution.  I do understand that this is not an inconsistency as there are other factors in the making of the determination, however for one who is skeptical of common descent; I think the second claim takes away from the first.  I also do not think it has been demonstrated, that because these ridges which turn into gills in one embryo look like these ridges which become something completely different in humans and other mammals is evidence of common descent.  It may fit with the story, but similarity as we have seen, does not show common descent necessarily.  Also in the early stages of embryo development, considering what you are going from, to what the end result is, I think it is reasonable to expect a great number of things, to have a similar appearance at certain points.   The fact is that in humans, these are never gills, and do not have anything more than a similar appearance at a certain stage of development.

With respect, I think you have their reasons for 1) illustrating what can only otherwise be known by data, since you can't easily (or at all) photograph some of these things that warrant visual representation-- in other words, something is not fake simply because I draw it to show how all the pieces come together; it's why we draw the center of the earth, to show the core, mantle, etc.-- and 2) their reasons for making the comparison to development, both very confused.

DNA does not represent a blueprint for an animal. What it represents are a set of "dividing, differentiating, and folding instructions" as the embryo goes from being a ball of stem cells (by simple division) to a hollow sphere and then folds in on itself to form the layers which begin to differentiate into new types of cell. At every stage, it keeps folding and copying and making new types of tissue in order to form that system. We can now "read" those instructions in the DNA, but we already knew they were there from embryology, because we could watch each stage and see the same processes  at work, and only later  processes turned those embryos through the necessary additional folds and changes to become something further down the chain of evolutionary development. We can SEE it, even though it's hard represent visually because in real life, tissues are hard to differentiate because everything's nearly the same color. So we make nice, pretty drawkings; bird and fish (etc) identification books are often done by artistic renderings rather than photographs, to help highlight some of the features that identify the real thing.

So you're right, the gill slits "never become gills"; what they do is start forming the same way that tissues in fishes, which have the DNA to make it keep developing into gills, form. They later will take a different path in the "switching and folding game", and turn into the structures we have in our throats to make sound. Evolution often works like that, taking sets of instructions and turning them in a new direction.

In other words, we share (from our common ancestry) the developmental Steps 1-58, say, but at Step 59 our DNA says to do something different, and the switch-and-fold process turns in a new direction that continues via the "updated" set of instructions that developed in one of our ancestors, after the split from the creature that doesn't have that set of instructions. There may even be other aspects of development that remain mostly unchanged from the set inherited equally-intact by our relatives; that's why Neil Shubin's book is called Your Inner Fish.

You're quite right, that just because similar things appear it does not mean they arrived by common descent; that's what convergent evolution is, period. Closer examination can tell you, via other traits, whether or not the similar design emerged because the creatures share common gene pools that passed the trait down, or whether it is the result of convergence-- an organ or system that works so well that it will be heavily selected for, in gene pools that produce that structure. One of the most famous ways we can show this is to look at the eyes of octopi and those of humans. They seem extremely similar, at first glace, but a closer examination shows that they develop in completely different ways, especially with regard to how the light-sensitive nerves grow and develop; ours run from the retina to the inside of the eyeball and back out through the "blind spot" in our vision, which our brains correct for so we do not see it without covering one eye, while the nerves from the retina of an octopus go straight back to the brain, and thus produce no blind spot.

Finally, common descent can also be demonstrated by looking at the genomes, in which non-coding sections (ones that don't do active things that can be acted upon by Natural Selection pressure) are simply passed down relatively intact, generation to generation, and thus contain "markers" which can be used to track family-tree patterns and see if species are related in that way. It is something that would have shown evolution via common ancestry to be 100% false, if it had been false; instead, it validated the Theory to a degree that was not possible, before. There is no question in anyone's mind that we know how this works.

It's not a "story". It's not something they're throwing out evidence to confirm as true. It simply is the way things are, and all signs point to it.

[jenny1972]

Okay, so in that case- how can you be sure that other parts of the bible are to be taken literally? What are the rules to determine what is literal and what is metaphorical?

Before the NT scriptures were written and the canon of the Bible finalized, God established an infallible Church which He continues to guide by His Holy Spirit.

That Church studies these things very, very carefully.

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It was an official Church position.

And even if infallibility refers to faith and morals rather than facts, you'd still have to explain the moral lapses that caused even the highest members of the Church hierarchy to shelter criminals. You'd have to explain the popes who in the past maintained mistresses, or came into the position by foul play. I know what you're going to say, "The Church is infallible, but the people are human", but the Church is the people.

The idea that your church is infallible is laughable. You should know better.

I agree, PT. The only positions that we claim are infallible are Church doctrine. The people within the Church can and do still make mistakes or do things that are very wrong. No Catholic should claim otherwise.

yes but the PEOPLE within the church , you know the ones who do things that are very wrong , are the ones who determine church doctrine . Church Doctrine was created by humans not God .