We are all transitional species

There is a debate from ABC (link) between Kirk Cameron and Ray comfort and the Rational Response Squad, in which they discuss evolution. Cameron and Comfort have poor arguments against evolution even for creationists. Cameron bring out the standard "there are no transitional fossils" line, complete with silly pictures of what he thinks a transition should look like. Unfortunately, the response squad blew the response.

They said that we are all transitional species, everyone in the room is. Of course, that's wrong. I think I know the point they were trying to make, but they failed utterly to make it. What opponents of evolution never understand about transitional species, is that you can never tell a species is transitional by itself. If all you have is one organism, there is nothing about it that says it is transitional. It is only transitional in comparison to something that came before it and something that came after it.

That is why claiming that everyone in the room is transitional is wrong. There is nothing after us. I suppose for those of us with children, we could say that we are transitional between grandad and grandkid, but that isn't the point he was making. He wanted to make the point that a transition doesn't look transitional by itself, but only in reference to other species, I think.

A transitional fossil does not look incomplete. It is absolutely impossible to tell whether an organism is transitional by itself. It is well adapted for its way of life, every organ and structure is fully formed and functional. There is no difference at all between a species whose line will lead to extinction and one that will lead to other species. Only in retrospect can we see that this organism has some traits of species before it and some of those after it. Archeoptyryx is a transition only because birds eventually evolved. While it lived, it was fully formed, and it had no structure struggling to be something else. Perhaps seals today will eventually give rise to fully aquatic organisms. Then they will be transitional, in retrospect. Or perhaps they will change little.

There are many other ways in which transitions are not understood. People fail to understand that it is the traits that are transitional, not the organisms. Cameron was thinking of evolution as a ladder, imagining direct transitions between organisms that are the end twigs of a bush. The common ancestor may have resembled neither of the descendants. But the most common misunderstanding of transitions is the persistent belief that a transitional species would somehow look different from a non transitional species. It is unfortunate that the ignorance of evolution is pervasive enough that a caricature such as what Cameron presented could actually convince anyone.