I don't want to get into the weeds on this but I just have to point out that this is just such a great example of bias confirmation/blindness. "The first to ever exist with bones"? You couldn't possibly know that, first of all, but more importantly, does it ever occur to evolutionists to ask where the bones came from? Did the bones come as a result of the fish's attempts to use their fins as legs or was it that the use of their fins as legs was made possible and thereby indirectly caused by the existence of the bones? In either case, was is just pure blind chance that it was the pectoral fins that got the bone or is it that the whole skeleton was bone and if so, why? Where is the survival advantage for the oddball first fish with bone vs. the fish's mother who had no bone but managed to reproduce and make him? Who would the first bone fish have reproduced with in order to have bone fish babies?Ok!
1. Lobe-finned fish are the first to ever exist with bones. Prior to them, it was just sharks, skates, rays, and fish that either have no rigid internal structure (think hagfish) or those with osteoderms (natural plate armor) on the outer surface
Such questions are as endless as they unanswerable but the evolutionist just goes right along on his merry way believing that, "Lobe-finned fish are the first to ever exist with bones." or a thousand other similar unfounded presumptions and call it a scientific theory.
"Their fins have become..."2. Lobe-finned fish are called so due to their stubby, almost leg-like appendages. Their fins have become more rigid and compact. Look up a coelacanth to see a good example. Some lobe-finned fish (henceforth called lobies) alive today use their stubs to "walk" along the bottom of the ocean. That is exactly what happened to shallow water lobies: some started to crawl.
It just astounds me that, what I think are, for the most part, well meaning, scientifically minded people, just do seem to be able to detect their confirmation biases.
Okay. Complete fantasy but, okay.3. After millions of years of evolution, we have a lobie that has adapted to breathe air briefly, a fantastic way to avoid predators in a world where all of those predators are underwater. Likely this occurred via the swim ladder being co-opted into a simple lung (something that lungfish today, as well as arapaima, and some catfish, can still do now: breathe air with their swim bladder or lungs). The stubby fins become more and more leg-like as the eons pass, because the lobies that CAN get out of the water don't get eaten as often as those that cannot, and they survive and reproduce.
No competition for food on the surface?4. A few million more years and we have a creature that needs water to survive, but can also come out of it if necessary and for long periods of time. There is no competition on the land for food because nobody else is here yet, other than Arthropods. This creature flourishes with its stubby legs that it uses to drag its body along (like a mudskipper).
Just how many unverifiable assertions are we going to need on this journey toward legs?
5. Those stubs are refined over millions of years until they are primitive legs, like those that a newt would have. And in fact, this is where the fish become amphibians. The legs get refined over time due to this: those creatures with a better ability to move around on land are better adapted to survive and reproduce. You start with a knub, and in the next few thousand years a mutation produces lengthened fin bones, which over many more millions of years become digits (think: whale fin bones for a crude example). And voila, you have a working leg.
Hope that was helpful.
Okay, yes, actually, it was.
The critical point being that there was a long list of amazingly lucky genetic mutations that just so happen to coincide with circumstances that would just so happen to allow them to be useful and thereby continue to exist which led to the next astoundingly lucky mutation that just happened to be of use to the already multiple time genetic lottery winning line of fish. One might wonder why none of the land animals look anything like fish with vestigial dorsal fins and gill plates but that's a discussion for another time.
The point of my question was to get exactly the sort of thing you've offered. So, let me ask you two questions...
First, is there any other path that legs have taken on their evolutionary journey to legdom? How, for example, did spider legs or insect legs evolve?
And lastly, if, while using legs to get around, you occasionally encounter obstacles that you have to step over (not around, only over); would sufficiently long legs evolve all at once or would some have legs that are too short (and/or too long) leaving only the 'just right' legs to reproduce?
Clete