How much is too much evolution?

You are operating under an assumption that all of these changes are handled within life, due to life's systems that are built to take care of such things. I'm telling you like OOL this isn't the case, something new like producing overtime generations upon generations acquiring a new system or limb is outside of a living system's normal operations. There are functions within an established lifeform that handle changes, yes, but that does not mean however that they will make additional changes and build on each one until something like a heart appears where there wasn't one before without destroying what was already there.

So far the only point I've made is that major morphological changes don't require major genetic changes.

If you are going to add a limb, a lot of resources will go into that endeavor suggesting it's no big deal sort of defies logic at every level.

By all means please educate me on the genetics and development of limb formation.  What does 'a lot of resources' mean?  What are these specific 'resources' of which you speak?  Do go beyond generalities and ambiguous statements like 'a lot of resources'.  Please expound and lay out the details for me of what's required to go from fins to limbs.  How many new genes do we need?  How much new genetic information (or new 'code' as you say) do we need?  Give us some numbers to work with.

Well, let's see, since you don't seem to be able to figure it out for yourself! Anything that keeps an arm or a leg alive is pulling from the resources that the body has are resources that beforehand wouldn't have been required. 

I do know quite a bit about the genetics and development of limb formation and the fin to limb transition.  Quite a bit more than you.  This major change in morphology does *not* require massive genetic changes or major changes in 'code' or major increases of new information and new 'coding'.  But you keep insisting that I'm wrong, so by all means set me straight.  If I'm wrong then how many new genes and how much new 'code'/genetic information *do* we need to change a fish fin into a tetrapod limb?  Do tell.

As I said before, something new verse something in a well-established system are two different things. This is why I referenced OOL, nothing about it was established it has to come from scratch and when you alter an established system to do something it has never done before, this isn't a small tweak to code.

First, you are the one who brought up the vertebrate limb, not me.  So let's avoid speaking in ambiguous generalities and talk specifics.  Second, no evolutionary biologist on the planet claims (or has ever claimed!) that the tetrapod limb was a new structure or novelty that originated *de novo* ('from scratch').  It has long been held that the tetrapod limb arose by modifications to the fish fin.  This is supported by both paleontological evidence and evidence from genetics and developmental biology.  And as it turns out the underlying genetics *is* a matter of 'small tweaks', so to speak.  You again continue to insist that I'm wrong, so by all means set me straight.  If I'm wrong and it's not just a matter of 'small tweaks', then please tell me how big the genetic changes in 'code' need to be in order to modify a fin to a limb. How many new genes do we need?  How much new information (new 'code') do we need?  

.....Or do you not actually know?

I was under the impression that you believed there was a common ancestor for all life, this lifeform, in the beginning, was structured; how? Was it a multi-cell creature, a single-cell creature, and from there, you believe all modifications started and continued, correct?

One subject at a time.  You brought up the vertebrate limb so I am addressing it.  The underlying genetics from fin to limb involves genetic 'tweaks' or 'tinkering'; *not* massive amounts of new information 'code'.  You keep insisting I'm wrong and that such changes do not involve minor tweaks, but major informational changes.  So how big, then, do these genetic changes actually need to be to change a fin into a limb?  How many new genes are needed?

Do you or do you not actually know???

I'm still on topic; from a single cell, we go to limbs, systems, organs, and so on. These were programmed into the first cell right off the bat, or did they show up later as far as code is a concern?

Actually,  as I noted in post #67 you raised a number of different issues, which I suggested we take in turn one at a time starting first with the point that major phenotypic changes usually don't require major genetic changes.  I repeated this point again in post #82.  You continually insist that I am dead wrong about this and that major phenotypic changes require major genetic/informational changes and brought up the example of the vertebrate limb where in post #83 you wrote:

"If you are going to add a limb, a lot of resources will go into that endeavor suggesting it's no big deal sort of defies logic at every level."

Since that post I've simply been trying to get you to clarify what you mean by 'a lot of resources' and what specific 'resources' you're speaking of, and if I am wrong about small genetic changes needed to go from fin to limb, then asking you to set me straight by telling me how large the genetic/informational changes need to be, how many new genes are needed, etc.

Your responses have been ambiguous at best to evasive imho.  I see no reason to move on when we still haven't got past the first point.  That is, unless you've changed your mind.

Have you?  Are we now both in agreement that changing a fin into a limb does not require major changes in genetic information/'code'?

No, a limb requires muscles, bone, ligaments; if it has paws, there will be claws, fur, veins, arteries, and so on. The form is different, the functions are different, so the ability to use one will be different from the other. So I'm afraid I have to disagree.

Then we are back to my original question.  The scientific evidence shows that the change from fin to limb is *not* due to any substantial increase in genetic information or suites of brand new genes, but is mainly due to 'tweaks' and 'tinkering' with genes and genetic regulatory systems that already exist.  You, however, keep insisting that I am wrong, and by extension the scientific evidence, which you show no awareness of nor interest in learning about, but just simply dismiss it out of hand and as a matter of course without even knowing anything about it.  

Now usually it is customary for the person who disagrees to not just simply be contrarian, but to provide correction, so I'm waiting for you to do so.  If I'm wrong and the fin to limb change requires major genetic/informational changes and not minor 'tweaks' and 'tinkering' with what already exists, then I'm waiting for you to tell me how large the genetic/informational changes need to be.  How many new genes are needed?  How much additional information/'code' is needed?  And how you know all this? 

Please tell me that you have some actual evidence to back up your claims.  Please tell me that your argument goes beyond computer programming analogies and your personal opinion of how you think things must be, and that you have some actual facts to support your claims.

Do you???

It is a simple matter of cause and effect where I have been talking about life's beginning, the first changes that have supposedly brought into life systems where there were none or limbs where there were none, you! You are talking about established systems where you suggest a little tweak could do it. Even that I disagree with because you are suggesting an established system will just take it upon itself to make changes that could amount to structural changes along with different functions all coming into play.

Yet there are instances of a limb growing as a result of one gene. I wouldn’t call that a “suggestion” that that is the case, more like experimental confirmation. If your claim is true, why do we see instances of one-gene controlling the growth of a limb?

@TruthMuse, 

So you don't actually have any facts to back up your claims.  Your argument is limited to computer programming analogies and your personal opinion of how you think things must be and what seems logical to you.  But you don't actually have any hard evidence to support it.  

If I or anyone is to be persuaded to adopt what you're saying as truth and reject the scientific evidence, then more is needed than just your personal say-so.  You must provide counter evidence that calls the scientific evidence into question.

Right now all you have is the equivalent of a hypothesis- an educated guess about how you think things should be based on computer programming analogies and what seems logical to you.  The problem is the facts don't actually support this but show otherwise.

The facts are that the development of all the different types of limbs and appendages that we see in vertebrates from fish to chickens to mice and so on is controlled by the same two sets of developmental regulatory gene clusters known as HoxA & HoxD.  The diagram below shows how different vertebrate appendages from limbs to fins are the product of the same sets of homebox genes that all vertebrates share in common.  The blue color shows where in the developing limb bud of an embryo the different HoxA & HoxD genes are expressed.  In other words, the facts show that the differences in appendages (from fins to limbs) is less the product of different genes and more due to how the same sets of genes are expressed differently spatiotemporally in embryos. 

Here is a closer view of the spatiotemporal expression of the same homeobox gene and how this changes the type of appendage that you end up with.  Thus, we see again that the diversity of vertebrate limbs is less about different genetic information and more about how the same genetic information is processed and expressed, where (spatially) in an embryo it is expressed and the timing of when (temporally) it is expressed during an embryo's development and for how long (duration).  Genes are like 'dimmer switches' that can be switched on and off, and also varied in intensity at different times and places in an embryo and for different durations.

This photo shows the development of a mouse hand and fish fin.  The 'autopod' of a vertebrate limb is the distal end where the digits are (fingers, toes; or fin rays in the case of fish).  A long standing problem with going from fish fin rays to fingers and toes is that they are constructed out of completely different bone.  Digits (fingers, toes) like in mice and humans and other terrestrial vertebrates develop from endochondral bone while fish fin rays develop from dermal bone.  You would be right to question whether such a change is possible and logically it would be reasonable for us to expect such a change to require completely different genes and different developmental pathways.  But as it turns out the facts of the situation are that the *same* genes are involved in both.  The proteins that are coded for by the genes were radioactively tagged so that they glow and their movement traced during embryo development.  The photo shows how in both cases the cells that make up the mouse toes and fish fin rays are due to the expression of the same genes; namely HoxA-13 & HoxD-13.  Here is an example of how the same gene in a different context yields a different result similar to how the word 'hang' has different meanings in Ben Franklin's famous quote "we must hang together or we will hang separately."  Thus, in the case of the fish embryo the HoxA-13 & HoxD-13 genes cause fin rays to develop from dermal bone, but in the mouse these same genes cause toes to develop from endochondral bone.

Just a few months ago there was another amazing discovery.  As you note there are major differences between fins and limbs.  Fins contain series of bones but there are no muscles attached to the bones (like there are in terrestrial vertebrate limbs like humans) and bones are not articulated with each other like we see with the radius & ulna (red) in humans.  I agree with you that it seems like the addition of extra bones with muscle attachments (where none existed before!) is a huge change that logically we would expect to require all sorts of new genes and changes in genetics and development.  But as it turns out the actual fact of the matter discovered just a couple months ago is that a *single* change to a *single* gene that has an important role in regulating the expression of developmental genes adds extra bones with *muscles* attached to the bones where no bones or muscles existed before!

There are many additional interesting studies I could cite.  They all tell the same story: contrary to what we might expect (i.e., that major changes in genetics and lots of new genes are needed), the actual facts show that the different vertebrate appendages from fish fins to limbs are less the result of increases in new genes and genetic information, and more the result of how the same clusters of genes are expressed differently spatiotemporally in embryos: i.e., where in an embryo genes are expressed (spatial), the timing of when genes are expressed during embryonic development (temporal), the length of time genes are expressed (duration), and the degree or intensity of expression (like a 'dimmer' switch).

The amount of information, the possible combinations are what here?

There's no significant change in information.  The change from fin to limb actually includes informational/gene loss (associated with dermal bone, for example).  As counterintuitive as it may seem, gene loss is often a creative force and patterns of gene loss are widespread in the animal kingdom.  But laying that aside the take home lesson here and one of the surprising discoveries over the past few decades is how contrary to expectation major phenotypic changes are often not associated with major genetic changes but tinkering with what already exists.  We see this particularly with the developmental regulatory homeobox genes common to all animals.  All animals essentially have the same developmental genetic 'toolkit' since before the Cambrian period.

(Regarding 'combinations' I'm not clear on what you're asking, but I would add that combinatorial genetics is also an important factor, where again it's less about mass amounts of new genes and genetic information.  Great differences in phenotypes result not only by how the same genes are regulated but how they interact with other genes in additive and combinatorial genetics.  This is how, for example, the same gene in one context will result in different phenotypes in another context just depending on what other genes it's associated with)