Creation vs Evolution

I am looking for someone to explain to me how time is measured using the speed of light when the actual distance that the source of light is coming from is unknown. I also don't understand Darwin's theory of evolution based on survival of the fittest. If man came from ape, why are apes still around? And if it was a certain kind of ape that man evolved from, doesn't the theory of evolution dictate that things evolve to survive? Wouldn't that mean evolving ASAP. In other words, wouldn't it be more logical for a type of ape that needed to evolve for survival purposese, to evolve into an ape type that was already carrying all the genetic code for survival? Just seems that it would have been a lot quicker and efficient (aspects required for survival). Oh, and one more category that I don't get - Carbon 14 dating. According to the research that I've done, Carbon 14 dating (a.k.a. Isotope dating) is only measurable for a limited amount of time. There comes a time that the ability to measure loss of isotopes becomes unmeasurable. So how to scientist come up with numbers in the millions of years old (scientifically that is)?