"One of the classic arguments in favor of the evolutionist claim that all species have a common origin is that species show all sorts of similarities which can't be due to chance. Indeed, the enormous mass of odd similarities that he found in his studies of nature around the world is what convinced Darwin of the common origin of all species, and he didn't know half of the similarities that we know today. Thus, the standard evolutionist argument is: If all those species are much more similar than mere chance would allow, then they must be related. However, a greater than chance similarity between organisms only proves precisely that: greater than chance similarity between organisms. There exist other possible non-evolutionist explanations for the same facts, the most popular of which is that species were designed by some kind of ultra-powerful being. However, we don't need to go to such extremes to put the argument under stress."