What is the difference between r-species and k-species?

Answer 1

Those are reproductive strategies that identify certain species. R-selected are those that reproduce rapidly and produce a lot of progeny; bacteria are an example. K-selected are those that reproduce very slowly and are slow to mature; humans are a k-selected species. Population density is the number of organisms per unit area. Some organisms don' t like to be crowded, so the density can affect the population size. Also, some limiting factors are density-dependent, like food or living space.