Lakewood Fellow,
There are two issues here. One is what the experiments show, i.e. what has been observed, and the second is whether macro evolution follows as a matter of inductive logic from micro evolution.
The experiments have not been able to demonstrate macro-evolution. While changes to fruit flies, who reproduce in much quicker cycles than mammals, can be achieved and groups can be isolated in to what is arguably different species of fruit fly, they have not be able to turn a fruit fly into something that wouldn’t be characterized as fruit fly under our current system of classification (and often mutations reverse themselves in later generations).
This phenomenon, that change can be achieved relatively easily, but it remains with in bounds is not uncommon with biological organisms. For example there is great variation among humans in intelligence but in subsequent generations the offspring of super-smart and super-dumb humans trends back to the mean. They do not keep on getting smarter and keep on getting dumber.
Similarly, with artificial selection, while great variation can be achieved by breeding dogs, breeders are still limited in how far they can change dogs. They cannot get them to no longer be dogs.
I can think of two biological explanation for why this might be. First, most mutations are the switching on or off of genes that are already present, or the deletion of genes altogether. To make a leap from fish to lizard, however would require mutations that create new genes, which are relatively rare. (Furthermore if there is a base norm of an organism, the mutations might just be random variations of norm and will eventually revert back to the norm over time especially if they are not isolated).
Second, to create a large scale change you will often need numerous mutations working in concert, one-point mutations may not be sufficient. So small change of the one or two-point variety (such as is common with bacteria) might be easy, but large scale change might be very difficult.
I was not making statement of belief or fact as to myself when I described the different things people mean when they say “evolution.” I am just trying to clear up confusion and to help in the defining of terms.
I am personally uncertain about the validity of the Neo-Darwinian theory as an explanation of life’s diversity. There are a lot of questions on it that are better than the answers. On the other hand there is pretty decent evidence for common descent. If one dispenses with the Modern Synthesis, what is there to replace it?
I have some ideas but that is well beyond the scope of this post.