acorns have the potential to grow into oaks
Seeds to trees: Have you really observed potential, or have you concluded potential by what you’ve observed? We can repeatedly test and observe in the present a seed producing a tree, and then be satisfied that a seed grows into whatever kind of tree the seed originated from. Over successive generations, limited varieties appear. This is not the same proposition of common descent of that tree and all life, which you can only hypothesize without observing it in the past or anything like it in the present.
If you are going to count speciation as a step "backwards", what are you going to count as a step forwards"
The much celebrated arrival of the salamander to new species status is not the step backwards. It's the fact that what earned him that status is fewer options for breeding. "Forward" would be the ability to breed with other species of salamander with which he had been previously unable. Or a significant increase in body size. Or development of scales for protection. Or wings. Big teeth. Lose the cumbersome tail and walk upright. Of course, all this would take way to much time to be able to completely observe, yet you still assume that it has occurred.
I don’t know for certain that the end taxa of the ring species refusing to breed with each other is from a loss of genetic information by mutation or otherwise. My point was that it seems at least a small step backwards in an evolutionary scheme, and my original question (in response to the top post in this thread proposing "Is there a better proof for evolution [than] the ring species?") is how this demonstrates the potential of big changes forward. You did state upthread that "ring species don't demonstrate that potential, so in a way you have answered. It's been suggested that I visit a different thread for discussion of "new major structures" so I may do that. Thanks for the discussion, it was interesting.