Encyclopedia of Global Resources part 51 provides a wide variety of perspectives on both traditional and more recent views of Earth's resources. It serves as a bridge connecting the domains of resource exploitation, environmentalism, geology, and biology, and it explains their interrelationships in terms that students and other nonspecialists can understand. The articles in this set are extremely diverse, with articles covering soil, fisheries, forests, aluminum, the Industrial Revolution, the . Department of the Interior, the hydrologic cycle, glass, and placer mineral deposits. . | 448 Food chain Global Resources Background As early as 1789 naturalists such as Gilbert White described the many sequences of animals eating plants and animals being eaten by other animals. However the use of the term food chain dates from 1927 when Charles S. Elton described the implications of the food chain and food web concept in a clear manner. His solid exposition advanced the study of two important biological concepts the complex organization and interrelatedness of nature and energy flow through ecosystems. Food Chains in Ecosystem Description Stephen Alfred Forbes founder of the Illinois Natural History Survey contended in 1887 that a lake comprises a system in which no organism or process can be understood unless its relationship to all the parts is understood. Fortyyears later Elton s food chains provided an accurate way to diagram these relationships. Since most organisms feed on several food items food chains were cross-linked into complex webs with predictive power. For instance algae in a lake might support an insect that in turn is food for bluegill. If unfavorable conditions eliminate this algae the insect might also disappear. However the bluegill which feeds on a wider range of insects survives because the loss of this algae merely increases the pressure on the other food sources. This detailed linkage of food chains advanced agriculture and wildlife management and gave scientists a solid over view of living systems. When Arthur G. Tansley penned the term ecosystem in 1939 it was food-chain relationships that described much of the equilibrium of the ecosystem. Most people still think of food chains as the basis for the balance of nature. This phrase dates from the controversial 1960 work of Nelson G. Hairston Frederick E. Smith and Lawrence B. Slobodkin. They proposed that if only grazers and plants are present grazing limits the plants. However with predators present grazers are limited by predation and the plants are free to grow to the limits
