Help Me Understand

[rexbeccarox]

Can all christians that don't believe in evolution explain to me your problems with it. It is just really hard for me to rap my head around someone not believeing in evolution in the 21st century, so it would make it easier if I understood exactly why you don't. And maybe I can help you through your confusions, maybe not.

Thanks!

lol i dont think there are many christians here maybe try posting this question on >snip<

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There are three Christians contributing on the previous page alone.

[TheRocketSurgeon]

So... on to the second category - the fossil record.

The fossil record shows the appearance and for many the disappearance of creatures and plants throughout geological time.  This begs the question of how these creatures came to be.  The fossil record is still incomplete, and by it's very nature shows us snapshots in time.  I always like when a creature which is believed to be extinct for millennia suddenly shows up. 

Charles Darwin said

Geology assuredly does not reveal any such finely-graduated organic chain; and this, perhaps, is the most obvious and serious objection which can be urged against the theory. (The Origin of Species)

And despite a largely expanded fossil record this is still true.  We do see some similarities, in which we can imagine a common lineage, but I am not persuaded by the evidence I have seen.  It is still not a finely graduated chain which is described.  I have also become leery of drawings presented as evidence.  I have found at times, where claims and similarities are greatly exaggerated based on scant fossil evidence.  I do want to know what they are basing their conclusion on what are the similarities and differences, and what fossil they have. This is often lacking at least in the popular articles.

Also, I do believe that the fossil record does show a punctuated equilibrium.  Where creatures suddenly appear fully formed, and remain largely unchanged for their time in the fossil record.  Similarly in events such as the Cambrian explosion we see major changes in a relatively short period of time.

Also just to be up front - I do question some of the assumptions in dating.  We are assuming that the daughter isotope is completely removed during formation of the rock.  Also the dating is not done on the fossils themselves, nor the rock in which they are found (you cannot date sedimentary rock in which most fossils remain).

Well, I'll start with your Darwin quote. The fact that you listed that tells me you have not read his book. Creationists are fond of quoting Darwin's "this is a problem for my theory" statements, found in On the Origin of Species  and elsewhere in his writings, but it's just the way he wrote. He would start with the objections he expected to hear, from those to whom he was showing his radical new idea, and then continue on to explain why it was not a valid objection. For some reason, there are entire organizations that delight in quoting his opening line, and then ignoring everything he says after it. Secondly, there are lots of things which were not known to Charles Darwin in the mid-1800s, when he was writing his ideas down, compared to our knowledge today. Not one scientist on earth uses Darwin as the basis for his understanding of biology, except for the law of Natural Selection, one of the four major mechanisms by which the percentages of genes expressed in a population are altered from generation to generation (the other "reducing" element being genetic drift, while mutation and recombination increase the variety of genotypes/phenotypes available for NS to operate upon).

I'm not really sure what you mean by "how they came to be". We know how species come to be; it's not a really complex question... though defining a "bright line" of what exactly constitutes speciation and/or a distinctive species can be problematic, depending on how one defines several factors in considering it so. Populations expand and fragment, and if behavioral changes or territorial separation cause two groups of the same population to cease exchanging genes within the gene pool of that species, then Group A and Group B will begin to diverge from one another with each generation, until at some point they are no longer able to interbreed and produce fertile offspring. As we know with mules and ligers, there can be quite a distinct difference between recently-related species before they cease to at least have the ability to produce viable offspring. Perhaps the easiest analogy for understanding species "creation" is to think of a family tree, and with isolated species groups as sharing a grandparent. "Cousin" species are distinct from one another, yet share a common ancestral population (the grandfather, in this analogy). Go back far enough, and every species on earth is a distant cousin.

The objection that species once thought extinct sometimes show back up isn't really an objection against evolution, but against zoology.

Seriously, though, it's a common misconception that things are trying to "evolve upward", or "toward" something. Older types which experienced insufficient selection pressure (being already well-adapted to their environments to the point that very few things caused them to lose members due to fitness problems), like sharks or alligators or turtles, stick around just fine as they were, as long as their environment does not change radically enough to place them under pressure, while other species may be under such selection pressure that they change fairly radically through each generation (though still by incremental degrees; even punctuated equilibria is slow, only appearing fast on a geological timescale). Humans are not any "more evolved" than a worm, or a monkey. 

Think of a sperical-shaped tree full of branches, ever expanding outward and branching new offshoots, but only having leaves (existing species) on the very tips. Some branches are thick and some are thin, depending on how populous that species is, but all are "expressed" only at the tip. Some branches dwindle and die out, no longer reaching the surface. Some split off in directions so radical it takes an expert to find the branch from which they originated, especially if the central vein of that old branch no longer reaches the surface. Pick any leaf on that tree to look at, and another from the far side of the tree, and you find two "equally-evolved" species. The old view of climbing a great ladder toward compexity, as described by Aristotle, is almost entirely mistaken, yet continues to inform our common view of how species evolve.

I'm curious to know exactly what your questions are about the fossil record, because I'm unfamiliar with any major problems with it. Sure, there are gaps, but one of the biggest finds in evolutionary biology's history, Tiktaalik roseae, was found as a direct result of our understanding of the fossil record and its geological stratification, because of another (descendant) species that was found that suggested it should have an ancestor like Tiktaalik.

[TheRocketSurgeon]

Just for fun, this addendum, an interview on The Colbert Report  with one of my all-time favorite evolutionary biologists, Neil Shubin, the discoverer of Tiktaalik and author of Your Inner Fish.

http://www.cc.com/video-clips/xgsf42/the...eil-shubin

Edit, with apologies... the original link didn't work as a video.

[Thumpalumpacus]

[...] Neil Shubin, the discoverer of Tiktaalik and author of Your Inner Fish.

A brilliant read.

[TheRocketSurgeon]

[...] Neil Shubin, the discoverer of Tiktaalik and author of Your Inner Fish.

A brilliant read.

It's what sold me on liking him so much. He just has a wit and a way with words; it made me look at some things with a fresh eye, and with a smile, a rare combination.  I cannot recommend his book enough.  His interviews are often just as remarkable... especially with Colbert, who kinda overruns him a bit because he's relatively soft-spoken, but for good comedic effect.

[Thumpalumpacus]

As for radiometric dating, I'll have to get home and on my computer. It's a little too complex to handle on my phone without clear references handy.

Given that we have several different checks on the accuracy of radiometric dating, the fact that a few percent of those samples return anomalous dates is quickly discovered -- that is exactly where the data touted by YECers comes from: double-checking.

Firstly, many rocks are susceptible to multiple types of radiometric dating. In the vast majority of cases, the different decay cycles agree with each other. In order to argue that one method is wrong, you would have to argue that all the other methods used on a given rock were not only wrong, but somehow produced the same error.

Secondly, we can observe radiometric decay in progress by viewing supernovae. Such stellar explosions produce copious amount of decaying elements, and by spectrographic analysis over time, we can mark the decay of one element into another. Not surprisingly, since all elements heavier than lithium we created in the bowels of such an explosion, we can see the decay rates of radiometric yardsticks used here on Earth out in space, where they aren't affected by climate of terrestrial geology. The decay rates we see in supernovae support what is seen here on Earth.

Thirdly, it is true that anomalous geology can affect decay rates. However, if our understanding of decay rates were so badly off, what would we expect to see with the dates extrapolated? What are the odds that every mistake the world over just happened to produce an older age, and moreover, roughly the same error? If would seem more reasonable to me that the dates would be more widely scattershot, given the varied geology from which samples are collected. After all, if, say, vulcanism produces pressures and heat which advances the decay of potassium into argon, why should K-Ar errors from non-volcanic regions mirror that error, in the absence of such influences?

eta: By the way, Roadrunner, thanks for getting me to dig back into the matter. It's been a couple of decades since college geology, and the rereading was good brainfood. Thanks.

[Thumpalumpacus]

A brilliant read.

It's what sold me on liking him so much. He just has a wit and a way with words; it made me look at some things with a fresh eye, and with a smile, a rare combination.  I cannot recommend his book enough.  His interviews are often just as remarkable... especially with Colbert, who kinda overruns him a bit because he's relatively soft-spoken, but for good comedic effect.

He conveys a wealth of information with a panache that, as a writer, I can admire for its craft as well as insight.

[robvalue]

It's perfectly reasonable to have doubts about any particular scientific theory. It's healthy, in fact, to investigate problems people say it has.

No theory is presented as cast-iron 100% accurate no matter what new information may emerge. Every single one represents our best attempt to model reality, and will be subject to further modification given new findings. It's even possible (though somewhat unlikely) that new findings would show the entire basis for the theory to be flawed, and that a new hypothesis needs building up from scratch. This is all part of the scientific process.

What is not reasonable is to conclude that because there are (what you consider to be) some problems with the theory, that you not only disregard it but insert your own entirely unsupported ideas in its place. If a theory is wrong, we need new sensible, testable hypotheses. We don't need fall-back positions of made-up stuff in place of simply admitting we don't know yet.

This is the problem where creationists (I don't know if roadrunner is one or not) present a false dichotomy between evolution and goddidit. Wrong. Either the theory of evolution is well supported, or else it is not. That's as far as it goes. For one thing, if you're going to insert a story in its place, any story that anyone makes up is as good as another.

[RoadRunner79]

---

Well, I'll start with your Darwin quote. The fact that you listed that tells me you have not read his book. Creationists are fond of quoting Darwin's "this is a problem for my theory" statements, found in On the Origin of Species  and elsewhere in his writings, but it's just the way he wrote. He would start with the objections he expected to hear, from those to whom he was showing his radical new idea, and then continue on to explain why it was not a valid objection. For some reason, there are entire organizations that delight in quoting his opening line, and then ignoring everything he says after it. Secondly, there are lots of things which were not known to Charles Darwin in the mid-1800s, when he was writing his ideas down, compared to our knowledge today. Not one scientist on earth uses Darwin as the basis for his understanding of biology, except for the law of Natural Selection, one of the four major mechanisms by which the percentages of genes expressed in a population are altered from generation to generation (the other "reducing" element being genetic drift, while mutation and recombination increase the variety of genotypes/phenotypes available for NS to operate upon).

I'm not really sure what you mean by "how they came to be". We know how species come to be; it's not a really complex question... though defining a "bright line" of what exactly constitutes speciation and/or a distinctive species can be problematic, depending on how one defines several factors in considering it so. Populations expand and fragment, and if behavioral changes or territorial separation cause two groups of the same population to cease exchanging genes within the gene pool of that species, then Group A and Group B will begin to diverge from one another with each generation, until at some point they are no longer able to interbreed and produce fertile offspring. As we know with mules and ligers, there can be quite a distinct difference between recently-related species before they cease to at least have the ability to produce viable offspring. Perhaps the easiest analogy for understanding species "creation" is to think of a family tree, and with isolated species groups as sharing a grandparent. "Cousin" species are distinct from one another, yet share a common ancestral population (the grandfather, in this analogy). Go back far enough, and every species on earth is a distant cousin.

The objection that species once thought extinct sometimes show back up isn't really an objection against evolution, but against zoology.

Seriously, though, it's a common misconception that things are trying to "evolve upward", or "toward" something. Older types which experienced insufficient selection pressure (being already well-adapted to their environments to the point that very few things caused them to lose members due to fitness problems), like sharks or alligators or turtles, stick around just fine as they were, as long as their environment does not change radically enough to place them under pressure, while other species may be under such selection pressure that they change fairly radically through each generation (though still by incremental degrees; even punctuated equilibria is slow, only appearing fast on a geological timescale). Humans are not any "more evolved" than a worm, or a monkey.

Think of a sperical-shaped tree full of branches, ever expanding outward and branching new offshoots, but only having leaves (existing species) on the very tips. Some branches are thick and some are thin, depending on how populous that species is, but all are "expressed" only at the tip. Some branches dwindle and die out, no longer reaching the surface. Some split off in directions so radical it takes an expert to find the branch from which they originated, especially if the central vein of that old branch no longer reaches the surface. Pick any leaf on that tree to look at, and another from the far side of the tree, and you find two "equally-evolved" species. The old view of climbing a great ladder toward compexity, as described by Aristotle, is almost entirely mistaken, yet continues to inform our common view of how species evolve.

I'm curious to know exactly what your questions are about the fossil record, because I'm unfamiliar with any major problems with it. Sure, there are gaps, but one of the biggest finds in evolutionary biology's history, Tiktaalik roseae, was found as a direct result of our understanding of the fossil record and its geological stratification, because of another (descendant) species that was found that suggested it should have an ancestor like Tiktaalik.

---

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.

[TheRocketSurgeon]

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