The other day, I googled the best arguments used against creationism. No worries, folks. They're mostly offering bald assertions, appeals to authority, and straw men. Any way, I did find an interesting graph. Actually, “interesting” is probably too strong a word. It's more like amusing. At least it sparked my interest in writing this post.
The author was trying to make the point that little changes can accumulate over time to create big changes. It's one of the Five Lies that Evolutionists Tell. Evolutionists say that the only difference between micro- and macroevolution is time and scale. By the way, I discourage use of those terms; evolution doesn't happen at all – neither micro nor macro. To make his point, the author showed how you could change the word AARDVARK to BASEBALL by changing only one letter at a time.
Now, as a lover of using analogies, I can appreciate how difficult it is to create a really good analogy. I normally wouldn't nitpick an analogy if I can at least see the overarching point its author is trying to make. However, in this case, there are such fundamental flaws in the analogy that I believe it better illustrates some of the difficulties of evolution rather than how evolution could progress.
Before I get into the difficulties in the analogy (and, by extension, with evolution), let me offer a thumbnail of what the author is trying to demonstrate. Evolution supposedly happens via mutation and natural selection. A mutation will occur in the DNA of an organism; on rare occasions, the mutation will offer a benefit to the host; because of this advantage, the host may live longer (natural selection) and leave more offspring which will inherit the beneficial mutation; eventually, the descendents with the beneficial mutation will replace the entire population. In the analogy, the changes in the letters represent mutations in the DNA. The accumulation of these changes can turn the ancestral species into a different species in the same way changing one letter at a time can turn AARDVARK into BASEBALL.
Did I misrepresent anything? The we'll continue.
The first problem is rather glaring. The steps in between AARDVARK and BASEBALL are just groups of letters that don't even make words. Going from words to meaningless letters represents a loss of information. Why would natural selections select mutations that don't gain anything?
For evolution to happen, a mutation must make the host more fit for that environment than before the mutation. For an arm to become a wing, certainly there must be thousands of generations in between the fully formed arm and the fully formed wing. Every step of the way, the mutated limb had to be more beneficial than the generation before it. It's hard to imagine a scenario where a limb that is not quite an arm but not yet a wing will be selected over a functioning arm. To imagine that it happened thousands of time is beyond incredible. Oh, and by the way, we only have a handful of fossils alleged to be transitional between a forelimb and wing. The thousands of in between forms that must have existed apparently left no fossil evidence showing the change.
Evolution is impossible if any of the transitional forms between the starting and ending species are one bit less fit than the generation before it. They'd be like the meaningless words between AARDVARK and BASEBALL.
The second problem is that evolution is not a directed process. The author of the graph knew he was heading toward BASEBALL and selected only those letters that worked toward that goal. Natural selection doesn't know that it's supposed to choose the limb that is more like a wing; instead, it will only select the one that is a more fit arm. Neither will it select the other features necessary for flight (like hollow bones, intricate feathers, or perching legs) unless those features offer some survival benefit to the earth-bound creature. Natural selection will have the tendency only to make a terrestrial creature a more fit terrestrial creature. It will not select mutations that could eventually make an earth-bound creature a flying creature.
The final flaw I see in the analogy is the enormous room for error. For the analogy to be realistic, all the steps in between the starting and ending words should also be words. Here's an example with a 4-letter word, PLAY – FLAY – FLAG – FLOG – FROG. In this case, every step in between is a real word. However, in each place there are 26 possible replacements which means you are far more likely to get a meaningless word than a real word. In the real word, mutations are far more likely to be neutral or harmful than they are to be beneficial. The harmful mutations in the DNA will far outpace the beneficial mutations which means for every beneficial mutation that a creature inherits, it will inherit thousands of unbeneficial mutations. This is known as genetic burden.
In 1995, A.S. Kondrashov published a paper in the Journal of Theoretical Biology where he discussed contamination of the genome by very slightly deleterious mutations. Over time, the ratio of harmful mutations to good mutations should become unbearable and he says, “This paradox cannot be resolved by invoking beneficial mutations or environmental fluctuations.” In the title, he asks, “Why have we not died 100 times over?”
In conclusion, the graph is not just an oversimplification - it's deceitful. It presents evolution as a simple, stepwise process where tiny, gradual changes and a whole lot of time could easily do what seems impossible. 1, 2, skip a few, 99, 100!!