KerrMetric
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Er.... how can you know this? What criteria gives you a measure of niche adaptation?
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The critters in the fossil record are fully adapted to their ecological niches.
Elephants loosing their trunks could be considered gross positive morphological changes.
(losing, not loosing -- pet peeve of mine)
Yes, in certain circumstances it could be. However, it is a loss of information and structure, not a gain.
Simply not true. Any duplication with additional point mutations fits a definition of increased information.What has never been demonstrated is an increase in information and structure.
Thank you for listing these examples of gross morphological changes.Why? If supposedly it has happened trillions upon trillions of times, why do we not have a single clear example? We do have some....sort of. Flys that develop a duplicate set of wings (they fly more poorly, would not have made it through natural selection). Deformities, such as cows with the rare, but existent extra leg,etc. So we do have some cases where existing structures are duplicated. But new structures -- new information -- spring fully formed in the fossil record.
Which of course explains why 90 percent of them are extinct.What we see in the fossil record is fully formed organisms appropriate for an ecological niche.
You do understand how long the cambrian was and that there are certainly pre-cambrian fossils of ancestors of trilobites right?. The cambrian layer as an example of fully formed organisms simply appearing is funny. There is a whole history of evolution for the creatures that appear there. It may have been the first place the eye appears but it certainly didn't simply appear with the creatures that we know as trilobites without an evolutionary record of the evolution that led to trilobites.If you accept the conventional geologic time frame for the geologic column, then in many cases rich, complex structures spring fully formed. Where are the fossils of things leading up to the trilobite eye? Why is there an explosion of complex life at the cambrian layer?
The record is in the genetics of every living organism.We now know that life is much much more complex than Darwin ever imagined. The wonderful self-replicating machinery inside every cell -- we're still puzzling it all out. Where did this come from? How did it develop? Why is there no record?
Very reasonable questions. I have more "reason" than "research" - and, as always, I'm prepared to adapt, learn and grow.laptoppop -- I noticed that you think that DNA correction kicks in for an unknown reason at an unknown threshold. Can you point me to some resources that might define either the activation mechanism of the correction mechanisms (as far as I've been able to establish, correction is always active though not perfect) or what the range of allowed variation might be.
It seems to me that in all the time we've been inducing mutations in organisms, we might have noticed one or two mutations that are always corrected because they pass the threshold of allowed variability. I wonder how you can justify a conclusion of such a limit or claim that repair mechanisms kick in at some point when we have no information suggesting fixed limits and all research suggests that every mutation has a chance of bypassing correction mechanisms (some more than others due to chemistry, not the future expression of the mutation).
I believe the variation is not coming from mutations, but from combinations of differing DNA, right?
Until YECs can define what counts as a gross positive morphological change, then it is not really much of an argument against evolution. And you would have to show that this change should be expected over the last 150 years to show any significance in not finding it. Realistically we are stuck with looking at the fossil record to show how small changes mount up to what you call gross positive morphological changes over million of years. Gish had some interesting comment on what he calls revolution in structure.These are valid questions. It requires a difference in the structures and how they are laid out, etc., not just a change in size. There is an ICR project just starting where they are specifically looking at determining the allowed variation range. Dr. Behe's new book describes his take on some of the limits of variation. Of course, he allows for more variation in history, but ends up with a goddidit answer because he doesn't want to deny common ancestry.
Yet it is exactly in this seemingly impossible transition from a YEC point of view, that we have an amazing series of transitions between jaw and ears in reptiles and mammals http://www.talkorigins.org/faqs/comdesc/section1.html#morphological_intermediates_ex2Originally Posted by Duane Gish
Gish, D. T. (1973) Evolution? The Fossils Say No! p57
The conversion of an invertebrate into a vertebrate, a fish into a tetrapod with feet and legs, or a non-flying animals into a flying animal are a few of examples of changes that would require a revolution in structure. Such transformations should provide readily recognizable transitional series in the fossil record if they occurred through evolutionary processes. On the other hand, if the creation model is the true model, it is at just such boundaries that the absence of transitional forms would be most evident.
The opposite is true at the amphibian-reptilian and reptilian-mammalian boundaries, particularly he former. While it is feasible to distinguish between living reptiles and amphibians on the basis of skeletal features, they are much more readily distinguishable by means of their soft parts and, in fact,, the major defining characteristic which separates reptiles from amphibians is the possession by the reptile, in contrast to the amphibian, of the amniotic egg.
p 58 (p 80 in some editions)
Many of the diagnostic features of mammals, of course, reside in their soft anatomy or physiology. These include their mode of reproduction, warm bloodedness, mode of breathing due to possession of a diaphragm, suckling of the young, and possession of hair.
The two most easily distinguishable osteological differences between reptiles and mammals, however, have never been bridged by transitional series. All mammals, living or fossil, have a single bone, the dentary, on each side of the lower jaw, and all mammals, living or fossil, have three auditory ossicles or ear bones, the malleus, incus and stapes. In some fossil reptiles the number and size of the bones of the lower jaw are reduced compared to living reptiles. Every reptile, living or fossil, however, has at least four bones in the lower jaw and only one auditory ossicle, the stapes.
There are no transitional fossil forms showing, for instance, three or two jawbones, or two ear bones. No one has explained yet, for that matter, how the transitional form would have managed to chew while his jaw was being unhinged and rearticulated, or how he would hear while dragging two of his jaw bones up into his ear.
Whether these can be explained by common designer is another question. Clearly according to Gish the transition between reptile and mammal is not what was expected from creation of kinds. But the issue here is where gross morphological change would be expected and whether it should be observed over 150 years if evolution is correct, or over longer periods and only in the fossil record, as has been foundIndeed. Here we have many similar structures in function, but a ton of variations and differing structures. Of course, to some similarity means common descent, while to me it means common designer and building blocks.
Isn't the YEC argument here that evolution could not take place because of limits in the ability of mutation to produce positive change. Even if rare individual mutations may occasionally have positive effects, they also have negative side effects. You cannot keep adding these partially positive mutations because the negative ones will build up too. The problem is that if there were purely positive mutations, or is negative side effects can be overcome by further mutation, then there is no barrier to continuous mutation. Going from "all the ones I've looked at have had negative side effects" to "virtually always come with negative effects" somewhat down plays the fact that this discovery shows what YEC thought showed evolution was impossible, actually happens.Yes, my terminology and understanding has changed. Thank you. I seek the truth, and I am glad to learn and be corrected and grow. I desire to be more accurate in both my understanding and my terminology over time.
Is the "tiny shift" not truthful? Is it not accurate to say that only the tiniest of percentages of mutations are positive, with the bulk being neutral and a large percentage being harmful? Tiny shifts represent learning and growth. I do not say "all" because "all" is not necessarily true.
The changes as recorded in the fossil record are much too big. The critters in the fossil record are fully adapted to their ecological niches. Why, with all the fossils, is that all we have?
Goal-shifting.Notto, I don't get the picture.
Genetic variation comes from both mutations and recombination. If you wish to know how recombination takes place, I suggest searching for 'meiosis'.I would claim that there is a range of allowed variation. If I breed dogs or cows or horses or whatever, I can emphasize certain traits. These ultimately have to be DNA changes, right? I believe the variation is not coming from mutations, but from combinations of differing DNA, right? How they combine, etc. is something I don't understand right now.
There's a reason why evolution in domesticated animals take place over 'reasonable amounts' of time. Our selective 'forcings' are more powerful than nature's selection. In nature, a combination of traits may determine the survival of the organism. A mutation changing the colour of a fur coat may not affect how that organism survives. But in artificial selection, we are only looking for one or two traits. Our selection is much more rigorous and strict. Not big enough? Doesn't get to pass its genes on. Not small enough? Doesn't get to pass its genes on. Ears flattened? Not what we're looking for, it's gone.Over time - a reasonable amount of time, not millions of years, I would bet that the dog I end up with would be indistinguishable from today's chihuahua.
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