Definition for R-selected species
From Biology Forums Dictionary
1) A type of life history strategy, where species have a high rate of per capita population growth but poor competitive ability.
2) They are populations that experience rapid growth of the J-curve variety. The offspring produced are numerous, mature quite rapidly, and require very little postnatal care. Consequently, this population grows fast, reproduces quickly, and dies quickly. Bacteria are examples of r- selected species.