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RAZD Member (Idle past 1427 days)  Posts: 20714 From: the other end of the sidewalk Joined:
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Hi Gregory Rogers, and welcome to the fray.
I will add my 2-cents worth to this discussion and try to avoid repeating what others have said.
A year ago I set myself the task of plumbing the depths of the debate to ascertain, if I could, the truth about this issue (bearing in mind that my field is theology, not science). To this end I would like to pose a series of questions, and would appreciate input from all sides. Excellent way to start.
My first question relates to the extent and depth of which mutations are capable, that is, of genetic ‘elasticity’, as it were. Namely: Is there any known process or element in the genetic make-up of animal organisms, or else anything within biology, that would actively stop or act as a barrier to so-called 'macroevolution’. In other words, anything known to genetics that would prevent transformation or mutation from one animal category to another, i.e., any process that would preclude, for example, an ape-like form evolving into a human being, a dinosaur evolving into a bird, and so forth. None known to date, and several instances of speciation have been observed, where a species branches into two species that no longer interbreed and share genetic material. This kind of branching is what lead to humans and chimps in the last 10 million years or so, and what lead to birds and flightless dinosaurs (birds are flying dinosaurs) over a longer time period. But I suspect that your question is not so much about common ancestry, as it is about changing one known type of animal into another known type of animal, and that is a different question.
It goes without saying that adaptation occurs on a lower level, eg, adaptation can result in different types of finches within the finch species, or else different breeds of dog within the dog species, etc. I believe all sides are agreed on this (so-called 'microevolution'). And that dogs evolved from wolves, yes agreed.
The crux of the debate, of course, is whether organisms can adapt significantly beyond this, from one animal to a different animal form altogether (ie, so-called 'macroevolution'). Thus I would be interested to know if there is any known genetic barrier that would actively prevent this larger step to a different animal form. Part of the problem here is the definition of what is a "different animal form" and how do you determine when that has occurred. To the biologist a "different animal form" occurs when a new species evolves, which is easy to determine when daughter populations no longer interbreed. Obviously there is no barrier to this happening, as it has been observed to actually in fact happen. Creationists seem to think a much larger change is required, but I have had trouble getting a good definition of that change from them.
As a layperson, I am struck by the inventive adaptations within the dog family (eg Great Dane compared with Maltese, etc.) Looking at this level of inventiveness, it might seem that the inventive step from one to another animal type as such is not unreasonable. Indeed, the variety in dog physiology is a testament to what mutations can evolve and survive when selection pressure is managed. The issue of selection pressure is important, as many breeds would not survive long in the wild, so what would appear in a fossil record would be a much smaller pool of variations. Dogs being artificial breeds selected by people protects them from natural selection purges. Remember that evolution is a two-step feedback response system that is repeated in each generation:
Like walking on first one foot and then the next. Both steps are necessary to the evolutionary path.
However, the creationist counter-argument is, I believe, that DNA make-up is like a computer software programme, and that it cannot develop outside of its basic programming. Thus a cat could never evolve into a dog, etc. This is what I was referring to previously about changing one known type of animal into another known type of animal. The answer is two-fold: (1) evolution works in nested hierarchies: multiple speciation events, result in a pattern that looks like a branching bush or tree:
For "D" to evolve into an "I" it would have to un-evolve to an "A" and then repeat the evolution steps to "I" -- which is highly improbable and unlikely. (2) theoretically it could occur with the right selection, as you can take the genetics of a cat and move them around and match the genetics of a dog (ie - you could build a dog DNA strand from a cat DNA strand by cutting and pasting -- which is what mutations do), but the problem is that selection pressure is not that precise a tool and evolution does not need to replicate an existing species DNA. When selection pressure pushes for development of an animal similar to another known animal what you end up with is convergent evolution. For example, flying squirrels and sugar gliders:
Flying squirrels are placental mammals while Sugar gliders are marsupial mammals, their common ancestor is back at the division of mammalia into these two fundamentally different branches and while they have superficially similar appearances their internal physiologies are different and they cannot interbreed. There are many examples of convergent evolution.
Of course, I have also heard the evolutionist argument that two different genes can merge and share their differences, resulting in a new genetic direction, and in this way new animal classes develop. Species, not classes. This would be one kind of mutation. We even have evidence of chromosomes merging and creating new species: donkeys and horses differ in this way, as do humans and chimps.
I hope I have stated the science correctly, as per above. So then, I would greatly appreciate all input on this point. A good start, and hopefully the responses are helpful to you. Enjoy
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined:
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined:
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Micro- and macroevolution are not so-called. The terms were coined by an evolutionist and I have found them in common use even at university level. However there is no precise universally agreed definition. Treat them as general rather than exact terms. Micro-evolution is the evolution within a species population. Macro-evolution is the divergence of species that no longer share genetic material via interbreeding. ie speciation is the demarcation line.
There is nothing that will actively stop mutations, although we also know that in some circumstances mutations are actively promoted in hot spots. ... Correct, mutation rates vary with location.
... There is however a passive barrier and that is the extreme rarity of beneficial mutations within the space of all possibilities. ... Irrelevant. Beneficial mutations occur.
... A change that requires several mutations before a benefit is produced are essentially beyond the reach of [neo-]Darwinian evolution. Demonstrably false. Neutral mutations and non-lethal but harmful (handicapping) mutations can persist in the breeding population, especially when carried on a beneficial gene. This allows later mutations to build beneficial aspects on them, especially when the ecology changes. There is actual observed documented instances of this happening (E.coli cloning experiment). Perhaps you are referring to Irreducible Complexity ... ? see ID acid test Indeed there is considerable variation possible within the dog kind. Similarly from hybrids we can infer that all cats, from tabby to tiger, are all part of the cat kind. ... Let's talk about clades and cladistics: With multiple speciation events, a pattern is formed that looks like a branching bush or tree: the tree of descent from common ancestor populations. Each branching point is a node for a clade of the parent species at the node point and all their descendants, and with multiple speciation events we see a pattern form of clades branching from parent ancestor species and nesting within larger clades branching from older parent ancestor species.
Where A, B, C and G represent speciation events and the common ancestor populations of a clade that includes the common ancestor species and all their descendants: C and below form a clade that is part of the B clade, B and below form a clade that is also part of the A clade; G and below also form a clade that is also part of the A clade, but the G clade is not part of the B clade. The process of forming a nested hierarchy by descent of new species from common ancestor populations, via the combination of anagenesis and cladogenesis, and resulting in an increase in the diversity of life, is what biologists call macroevolution. A "kind" would then be a clade with no previous ancestor. If (A) did not exist then (B) and (G) would be different "kinds" but (C) would still be descendant from (B).
... However we have never observed evolution from one kind into another. Nor does evolution ever in any way claim that this occurs -- because all evolution occurs within a species population, the descendants will always be offspring of their clade parent population: dogs will always be dogs and cats will always be cats. Nor would there be selection pressure in such direction, because all evolution needs accomplish is convergent evolution as noted in Message 26:
quote: Gene merging or gene duplication and conversion has never been observed. The closest they have come is identifying a family of similar genes that are assumed to have evolved from a common ancestor. Gene duplication has been observed in formation of polyploidy species. Gene fusion has been identified in several species, not just because the genes are similar but because they carry neutral insert markers that are identical, and the chance of that occurring is virtually zero. Assuming common origin is a robust and valid conclusion. Enjoyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
First I'd like to ask what is a species? Although some people may wish for a black-and-white criterion for defining species, this is unrealistic. [ Encyclopedia of Life ] See Definition of Species for a discussion of this fascinating topic.
The biological species concept is popular but many use the phylogenetic concept and it is often difficult to precisely define boundaries between species. ... It is difficult to use a biological or genetic definition of species for fossils, and the biological definition cannot be used on asexual species, and in these cases a phylogenetic definition is more useful -- to people (other species don't seem to care ... beyond 'mate-able' and 'non-mate-able'). It is also worth noting that the phlogenetic definition works well with cladistics even though it developed from classic taxonometric classifications.
... There are many cases where animals classified as separate species can produce viable and fertile offspring, e.g. lion-tiger, although their offspring is more often infertile. ... As in camels and llamas, but as has been pointed out there is also an element of opportunity, and there are instances where new species arise from mating of distantly related populations. So yes there is not black and white answer. But we also need to ask what is the purpose of making these definitions? What are they used for? And this is a purely human occupation in trying to make rational sense of the natural world, how we organize the information available in a way that makes sense. Now, I hope you would agree that the phylogenetic tree that shows clades and the patterns of descent of breeding populations is clearer when we label populations with the names of species.
I think this shows that current taxonomic classifications are only an approximation to biological reality. Of course, but a fairly accurate one when we can also construct a genetic tree and find that there are only a few areas of disagreement, that the basic picture is correct, and with two sources of such information that otherwise would not need to agree, fairly robust. Changes found were minor alterations not whole-sale revisions.
Similarly there is no universally accepted definition of kind. ... And I have not seen one (1) definition accepted by two creationists that is workable in identifying a single 'kind' - rather it is opinion (I don't know what a 'kind' is, but I know one when I see one). Again I refer you to cladistics and clades that, imho, is the clearest example of what creationists mean by 'kind' -- as I noted in Message 70:
quote: ... It is the nature of scientific research that sometimes (often) we have to adjust what we think to be true. Indeed, it is the nature of rational thought that "sometimes (often) we have to adjust what we think to be true" ... and that this holds for all areas of thought, even including religious opinions. Enjoyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
It makes you wonder whether all/most species whilst they're in the process of speciation meet up breed, move away, meet again etc etc and either finally separate for good like lions and tigers but can in principal interbreed or one outcompetes the others - as H. sapiens sapiens. Indeed, when llamas and camels can be bred it shows that genetic reproductive isolation does not always occur as populations diverge over time, and the ability to breed may survive thousands of years while populations spread to opposite sides of the globe. I remember a study of stickleback minnows done when I was at uni, and it showed that the hornier the male sticklebacks were, the more likely they were to attempt breeding with things that looked less and less like female stickleback minnows, ultimately trying to mate with a twig. This could be part of how biology encourages mating. When we look at the fossil record for Pelycodus we see some arbitrary species designations (linear speciation) and one speciation event dividing the breeding population into two separate populations.
The area between depths 1200 and 1400 could be a braided interaction period, where packs would divide, meet up, divide again, depending on ecological changes (droughts, floods, normal weather, etc) Were they fully reproductively isolated when they did finally divide for good? Or did they just move into different habitates and never met up again? Enjoyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined:
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First most of your post involves PRATTS -- points refuted a thousand times -- and I suggest you peruse An Index to Creationist Claims and
Arguments to Avoid Topic
| Answers in Genesis
... these should give you an idea about how bad creationist arguments are.
A section of DNA is a string of coded information and a random change will probably damage that information; far more likely than producing an improvement. Like making a random change to a software subroutine there are many more ways to do damage than to improve it. Similarly a random mutation is far more likely to damage the genetic code than to add beneficial genetic information. This just illustrates why a computer program is not a good analogy for DNA. It is actually more like a cooking recipe, where results vary with variations in following the recipe: change the amount of sugar in a cake recipe and you still have cake, just some variations will be more appealing than others, and thus that variation will be more likely to be repeated. Computer programs do not reproduce themselves so there is no natural selection.
Wild populations of bacteria often have a very small proportion of resistant individuals and the reason it is so small is that normally the mutation is harmful and is constantly being removed by selection. Only when exposed to antibiotics do these mutations give a net benefit allowing their proportion to increase and antibiotic resistant strains to develop. When antibiotics are removed the bacteria tend to revert to the original proportions. How quickly bacteria become resistant and how quickly they lose it depends on the selection coefficients in different environments. So.Wrong. Normally the proportion of any "wild" bacteria that are resistant to antibiotics is small because they are not exposed to it. When they are exposed, then natural selection favors the ones with resistance. When they are no longer exposed, then there is no selection pressure to maintain the resistance, and it fades in the population. For an example of how evolution actually works in situations like this look at Peppered Moths and Natural Selection.
But what about nylonase (and similar examples)? Adaptations like this appear to be part of the genetic toolkit of bacteria. E. coli have been found to develop the ability to eat nylon reliably and quickly, sometimes within days. This is relatively simple mutation and bacteria have the advantage of very large populations and rapid reproduction. I wonder if you read what you write ... certainly it appears that you do not see the irony of arguing that this occurs fast and reliably after starting out talking about how difficult it is to evolve a beneficial mutation ... " ... a random mutation is far more likely to damage the genetic code than to add beneficial genetic information." Oh but you pretend that there is a "genetic toolkit" to explain this. Curiously there isn't any evidence of any "toolkit" other than mutation and selection. If you disagree then demonstrate it, show the evidence for it.
Is this information adding? Genes that are programmed to be adaptable have the information pre-loaded into their design, and in gaining the ability to eat nylon it loses the previous function; so No. Wrong.Again. First let's deal with the information issue: see Irreducible Complexity, Information Loss and Barry Hall's experiments -- either "information" is added OR the concept of "information" is irrelevant to the process of evolution and to what can and does occur. There is no evidence of any such thing as "pre-loaded genes" ... and again, if you disagree then demonstrate it, show the evidence for it. If there are "pre-loaded genes" then (a) why does it take several generations for it to turn on and (b) why is it only turned on in a small set of the bacteria and not all of them? Inquiring minds want to know.
Now look at it from another point of view. How frequent are functional proteins in the sequence space of all possible combinations. Ann Gauger offers a neat analogy about the rarity of functional protein folds, calculated by her colleague Doug Axe. Hitting upon one is akin to standing outside the Milky Way and trying to strike a single quark held in the hand of a bather lying on the shore of Lake Michigan. It's that specific, mind-bogglingly beyond the reach of blind, unguided evolutionary groping. http://www.evolutionnews.org/...biologist_ann_g_2103194.html . Where there is a chain of beneficial mutations a result is achievable but a chain of a few neutral steps will blow the waiting time out of practical possibility, even for bacteria let alone humans. Here's a hint: when a mathematical calculation purports to show that something is nearly impossible but we have evidence that, for instance, there are enough proteins for life to go on, then the math is missing some critical element. Math does not prove what can and cannot happen in the real world, it can only model it. If the answer doesn't match reality it is the math that is wrong, not reality. See the old improbable probability problem for more on this type of pratt.
This is not a case of we don’t know; therefore God. We have the data and we can say we do know; therefore not Evolution. And yet, curiously, reality is not impressed with your argument, and life continues to evolve.
Evolution can achieve the trivial but is inadequate to achieve changes of even moderate complexity. What is the meaning of "complexity" and is it used by biologists? What do you think the evolutionary limits are for this creature:
Care to discuss? Now I can go into the errors you make in more detail when I have more time, but this should give you something to chew on. Enjoy Edited by RAZD, : added infoby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
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RAZD Member (Idle past 1427 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Let's see your math.
Seriously? This is basic stuff. It's why Lenski is using bacteria and not elephants for his experiment. Yes, show your maths, because you have made a mistake. Or this is your chance to show you haven't ... Again I refer you to the old improbable probability problem for examples of common creationist probability calculation errors. Or we can take another approach: This is a generation evolution cycle:
This is a two-step feedback response system that is repeated in each generation, like walking on first one foot and then the next. It repeats every generation. Based on evidence observed this occurs in virtually every breeding population in every generation, and we can thus say with high confidence that at least one new mutation survives in at least one individual from one generation to the next. For the purpose of maths we can say that this has a probability of >0.99, so we can use 0.99 and be conservative. The probability of another new mutation surviving in the following population is also, conservatively speaking, 0.99 The probability of both occurring is not 0.98, because they are separate instances and one does not depend on the other. This is like flipping a coin, each flip has an 0.5 probability of being heads (or tails) and every subsequent flip has the same probability because it does not rely on the results of the first flip. Now we can do a calculation of, say 10 flips of the coin, where each flip has a 50-50 chance, and then calculate the probability of precisely that pattern being reproduced, but that is irrelevant to the probability of the actual pattern having happened in the first place is 1.0 -- because it happened. Similarly the probability of all existing life forms having the genetic makeup they have is 1.0 ... they all happened. It's the difference between the probability that you will win the lottery and the probability that someone will win the lottery. Enjoyby our ability to understand Rebel☮American☆Zen☯Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
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