There is an attempt of late to save the crumbling faith of evolution by redefining it. One of these redefinitions is an attempt to claim that evolution is nothing more than the changing of alleles over time.
But Darwin did not know about genetics, so would it be reasonable for us to expect him to have explained evolution with this in mind? Science has to keep pace with new evidence continually coming to light.
For those who are reading, this is another recycled topic: RAZD started one about the definition of evolution and set out how you could test it: you can read it
here.
In short and simple terms, if we want to deal with the transformation of a cell to a human body, the information that has to be assembled to properly sequence genes is mind boggling. Of course, evolutionists like to break the complexity down into really tiny steps to make it more manageable.
Yet we see species changing in steps in the fossil record. The horse and the whale have been discussed several times here. We also know that for 3 billion years, the only fossils we find are simple single-celled organisms. It is speculated that the very first organisms were not cells, but the components of cells that reproduce, like RNA. But you are getting into the theory of abiogenesis here. We know that organisms change over time and this knowledge does not predicate that we also must know how it started.
Here's a thought. There is a great deal of evidence for the process of evolution in the natural world. There are a variety of ways by which evolution is known to occur, for example natural selection and genetic drift, and at the core of this is mutations in genes.
That given, intuition tells me that there are still more ways that aren't yet a part of that list. I believe that consciousness is capable of a lot more than most people give it credit for. What if a consciousness has directed evolution as well -- a group (species) consciousness, or maybe even a divine consciousness. A knowledge that certain changes to an organism would benefit that organism, for example if a new habitat has opened up (as indeed it did after the extinction of the dinosaurs). Consciousness (or maybe more correctly subconsciousness or superconsciousness) could guide those changes to happen in a way we could empirically see as evolution. Scientists would not like this idea because it would be difficult to test, but it's my own little idea at the moment.
As for symmetry, it's been done to death here. There are genes responsible for symmetry and some simple changes in those can result in dramatic morphological changes.
If you have something new to say, Russ, and not recycled comments like (in a nutshell) "it's impossible" or "it's against common sense," I'll perk my ears up.