Some folks like to pooh-pooh evolution as "unguided," inferring that something unguided could not have produced what looks to be the product of an intelligent designer. As a simple test, the above image is useful.
At first glance, it looks like a tattoo with a barcode, something a designer could have created. In reality, however, it evolved in a quite different way on a different planet.
The whole Intelligent Design movement being thrust on us by the marketing arm of the Discovery Institute in Seattle, Washington, is a rehash of hundreds of years old arguments about how life is too complex to have come about without the help of some outside mover/shaker. What most people ignore, forget, or are unaware of, is how much time it has taken for life to reach this point. People who rely on literal translations of ancient texts, such as the Bible, think our world has only been around for 60 to 100 centuries. Science has shown, however, that the Earth is over 3.5 billion years old and that's over 35 million centuries.
If something as complex and beautiful as the image above can happen in the virtual blink of an eye, is it so hard to imagine that nature's sculptor (evolution) built life as we know it from the building blocks of DNA, given such vast amounts of time?
Some may try to make a distinction of the micro- macro- evolution variety. However, as David Eller points out in an article on the subject, "... macroevolution is merely the accumulation of microevolutionary changes."
The ironic thing about intelligent designers -- of the human variety -- is that they are also responsible for the collateral damage they cause. Let's hope that we do not ultimately extinguish our own species because we ignored or underestimated the potential collateral damage of things like our contribution to global warming.