the race to exploit the environment is often decried as a human trait and something that is unnatural. Far from being unnatural,such exploitation is a vestige of our truly natural behavior. Holding back and not stripping resources would distinguish us from other organisms. All organisms change the conditions for life in their surroundings as they use up avilable resources. Ecologists refer to anything that is essential for the continuance of life and that is finite, as a resource. In natural systems, the growth of an individual or a population is limited by the resource that is the hardest to obtain. For example, water, light, nitrogen, and phosphorus are all potentially limiting resources for a seeding, but even if these were all abundant, an other resource such as potassium might be too scarce to allow growth. In that case, potassium would be the limiting resource.