In 1802 (when theories of evolution were getting off the ground, but well before Darwin published Origin), William Paley wrote, in his book Natural Theology, what has since become a standard criticism: the argument from complexity. In his example he pointed out that, if we found a watch on the ground, we would be in no doubt that it had a designer.
Scroll forward 200 years, and here’s fascinating video showing the results of a computer simulation of evolution. Starting from basic components – gears, springs etc – a functional clock evolves over many generations. And not just one clock – each time the simulation is run, it evolves a somewhat different solution to the same basic problem. Now what are the chances of that happening?