Based on the environments they live in, and the stability of these environments, two categories of organisms can be found. They are r and K strategists. This categorization describes the growth and reproductive rates of the organisms as well. r strategist is an organism living in unstable environments. Hence, they undergo rapid reproduction to stabilize themselves. Whereas, K strategist is an organism living in stable environments. Therefore, they are high in population and do not need to undergo rapid reproduction.