If r-organisms reproduce at such a high rate, why don't they usually reach their carrying capacity? If an r-population is moved into an environment where it has no predators and it is left there for a very long period of time, what might eventually happen to the population's reproduction strategy?

R-organisms are usually bellow carrying capacity (the maximum size of some population that can survive in the given environment). Those organisms are small and produce a great number of offspring. However, their life expectancy is short and many individuals die within a short time. Because of the high rate of death, they do not live long enough to reach their carrying capacity. Their life span is short, so even if predators were removed from the population, it would not be expected they will reach their carrying capacity.