An interesting argument made against life being designed is the path of the Recurrent Laryngeal Nerve (RLN.) If life was designed why would God take such an un-optimal path for the nerve — especially as seen in the giraffe?
The claim is that if you look at the RLN in fish you’ll see a more direct path, and as species evolved this nerve just got wrapped up and ended up taking a very indirect route below the heart. It makes sense, it looks like we can simply say “evolution did-it tm” and shrug it off. However, before we do that let’s think how un-useful that is towards our knowledge of biology. If we look at this “junk DNA” and say evolution did-it, we hinder our progression in science. It’s more interesting and useful to first assume there is a plan behind it and figure out why it is the way it is. That’s what we did with “junk DNA” and it ended up not being junk!
Even if I believed macro evolution was true (which I don’t,) I wouldn’t say that the indirect path of the LN was caused from it. How can evolution pay attention to such details like our eye lashes and eye brows yet take such a strange path for the LN? Just like most other things with evolution (like vestigial organs, junk DNA, eyes being wired backwards (http://www.icr.org/index.php?module=articles&action=view&ID=1742), etc.) it will probably end up going against the Darwin theory.
So what are some possibilities behind this RLN? I have heard some good ideas, check out http://www.icr.org/article/recurrent-laryngeal-nerve-not-evidence/
As a computer programmer I try to relate code to biology. I may look at code that someone else wrote and wonder why the heck they did that. I may even go as far as rewriting what they wrote trying to improve it only to find out that once my new elegant code is executed I discover major bugs. Then further digging reveals that what the original author did had an elegant purpose. I have the same view with life. Until we’re at the point where we can design life ourselves we should be very skeptical about un-optimal design. I am willing to bet that if we designed a giraffe from the embryonic stage to adult life with a short RLN we would find some very serious bugs.