The Definition and Description of a "Transitional"

Ah, but the theory does not say (and the evidence does not indicate) that you are an updated version of the chimp. You and the chimp are different updated versions of a common ancestor. As such, we can do things that the common ancestor couldn't and the chimp can do things that the common ancestor couldn't.And, of course, there's no reason why we should retain all the abilities of our distant ancestors if they're not evolutionarily advantageous. For example, blind cave fish (which have non-functional eyes) have obviously lost an ability that their distant ancestors had ... because they have no use for it and there's an advantage in their particular environment to not putting any energy into operating eyes. Eventually they'll probably lose the eyes altogether.So don't assume that we can do all that our distant ancestors could, or that we can do all that our distant cousins can.

Nope. The new version is just different. The differences can, and do, include new abilities or loss of old abilities. Because we have lost those abilities. It's difficult to come up with a solid answer to that question. It appears that our ancestors lived in savannahs, and were cursorial hunters. They didn't need to climb trees ('cause there weren't a lot of trees, and there wasn't a lot of food in the trees that there were), but they did need to run; it's quite possible that the changes that made us better runners required losing the good climbing abilities, because good climbing ability was neither advantageous nor disadvantageous in the environment in which our ancestors found themselves. Or perhaps good climbing ability in a human-like frame is incompatible with good running ability.Remember, we do not develop or lose abilities because it would be cool to develop or lose them; it happens because there is a difference in reproductive success in the current environment. Also remember that all changes work on already-existing structures, and that the process of evolution tends to find solutions that are good enough (seldom best) and similar to existing solutions to other problems. Perhaps good climbing ability would help to harvest fruits and suchlike, perhaps the ability to fly would help in geting away from predators. We don't have those abilities because they did not confer better reproductive success on the savannah (and, in the case of flying, it would probably be too far away from the existing structures to develop at all). I do believe that humans and fish have a common ancestor, but that's not the subject of this discussion. (Of course, we share a very large percentage of our DNA with fish, and we can trace the morphological changes through the fossil record). The point of my example is that there are obvious cases when an ability of an ancestor has been lost in a descendant.