river: Like Jan, it sounds like you're another one who doesn't really understand how evolution works. It's not a matter of conscious planning or something "conceiving" of something. The cuttlefish is the result of a long sequence of evolution from other living things. The apparatus and ability to change colour has increased over time, through different species. Think back to how this would have started. Suppose that one of the ancestors of modern cuttlefish developed a spot on its skin that could change colour to match the background colour, even if only slightly. That cuttlefish would, on average, be a little harder for predators to see than its fellow non-colour-changing cuttlefish. Therefore, that cuttlefish would be just a bit more likely to survive long enough to pass its genes on to the next generation, thus also passing on the colour-changing trait. Over many generations, those cuttlefish that developed better colour-changing abilities (by random variation) would tend to be selected by evolution and would come to dominate the cuttlefish population, all else being equal. Again, understanding is not required. Those plants that, by chance, balanced their pumping systems better than their competitors for the same ecological niche, would preferentially survive to the next generation, passing on the superior-pumping genes. See how it works?