When following the development of objects designed by humans we often see that big leaps are made using totally different approaches and materials. For example pens used to be made from feathers and were dipped into a jar of ink, then ballpoint and felt tip pens were developed. In living organisms, we see gradual change and the use of preexisting structures for new purposes but no radically new approaches. For example, the small bones in our ears originated from jaw bones, they didn't just appear magically on their own. What examples can you see of this contrast between purposeful design and evolution when you look at the development of cameras and the evolution of the eye?