I would argue that evolution is the only way to explain such "perfect" conditions. If you take a look at a change in a gene via individual mutation (this is what drives evolution after all) and take a simple example... a species of animal that lives on nuts. They have adapted thumbs with sharp strong claws for getting into these nuts. Now via normal gene behavior it mutates and gives an even sharper longer claw for getting into nuts - but there's a downside, this longer claw makes it harder for them to run away from a natural predator. So any animal born with this new sharper claw doesn't live to reproduce and thus that gene mutation ends with them. Now you have the same gene mutate that gives them instead a stronger but shorter claw and they can now escape their natural predator with ease as well as get into their nuts easier - with evolution this new gene becomes the norm. Now take that same concept into hugely more complex things like eyes and expand that out now millions of years and indeed you can see how the human eye, for example, gradually came to be. This is happening to all genes at the same time so many changes are gradually happening all at once - which is also a balance to factor in. The genes propagate out through the ideal "perfect" conditions naturally - no designer needed. This not only makes sense to an atheist like myself but it provides a huge sense of wonder and awe at the natural universe we live in.