Of course, this depends on your definition of the word 'intelligence' but it really did evolve. It evolve by way of our complex associative memory being able to make more and more associations. You've experienced this yourself.
Let's say your mother, when you were an infant, pointed at herself and said mama and, at the time, she was wearing a blue top. Your brain makes a basic association and the next time you see someone wearing a blue top you point at them and say 'mama'. Your mom said 'no that's not mama, that's dada' and your brain makes another association. And so on and so forth, on and on until you begin to become 'self-aware' or 'intelligent'. When someone points at something and says 'tree' your brain remembers that pattern and associates it to the word 'tree'. Then you see other things SIMILAR to it and your brain is able to associate those patterns to the word 'tree' again.
So it goes for primitive mankind. They point at a tree and say 'hmrph'. Their brain then associates the tree to the word 'hmrph'. It also evolves by way of experience. A bow and arrow holds it origins in skin-tanning. When a skin was being tanned, it would shrivel up in the heat of the sun. This was undesirable so the primitives had the idea to construct a frame and keep the skin spread by suspending it from leather strips. The trouble was the leather strips would shrink in the heat of the sun, too. That was no good. So another primitive (this being over the course of decades) had the idea to stretch the leather strip along a stick to prevent it shrinking. When he returned to the leather strip he found that, while the strip was fine, the stick had bent into a curve. He twanged it and it made an amusing sound. He showed it to others. They replicated it. Then someone else had the idea of putting a stick across the bow and twanging it off into the distance. Then someone else had the idea of putting a spear-tip on the end of that stick and, finally, you had the bow and arrow. Intelligence evolved, and you are evidence of that yourself.
Obviously, intelligence did evolve, as the volume of the human brain, and the achievements associated with that brain have increased over the many hundreds of thousands of generations. Also, I would tend to think that a certain level of intelligence is needed for conscious imagination, as you need to think to imagine.
According to writer for the Huffington Post Macrina Cooper-White, IQ has actually gone down by about 14 points since the Victorian Era. She hints that this drop in IQ may go back to the first true organized civilizations, where survival became more relaxed. There is no need to be able to rapidly assess the best way to live on a farm life. Indeed, an over active brain would be a burden, since farmers were ironically malnourished across the centuries (think peasants and serfs). Brains are very expensive to maintain (the brain at rest consumes 20% of the body's energy http://hypertextbook.Com/facts/2001/JacquelineLing.Shtml). Furthermore the belief that we are more intelligent then our ancestors is flattering, but likely untrue (at least to any significant degree). Sure we have nuclear missiles and computers, but those things are only possible piggy backed on the ideas of our ancestors. The saying "no need to reinvent the wheel" comes to mind. Was the first man to realize a wheel shape allowed the easiest movement of objects any less significant an inventor than the people who designed cars using those wheels? Thanks for humoring my long post. Surprised myself with my interest in this topic.
Experiments on Drosophila and E.COLI have produced variations on the theme, but no new species.
Other evidence, such as the still missing links ( missing because not yet found, or missing because they simply do not exist?) points to the same conclusion. Whatever their origin, species cannot be the result of biological evolution. The mechanism by which life unfolds itself, brought to our notice by the great Darwin. Confirmed by modern science. Given that evolution, in the sense evoked by the theory, cannot have taken place, intelligence could not have evolved either.