Trophic Levels 1. Decomposers feed on organisms from all levels. Food Webs 1. Cross-connecting food chains make up food webs in which the same food resource is often part of more than one food chain. Climatic factors determine patterns of vegetation and why unrelated species may have similar adaptations.
Barriers isolate species and restrict dispersal.
Biome distribution corresponds with climate, topography, and soil type. The form of the dominant plants tells us something of the weather conditions. B. Population growth and individual demands are stressing the environment. Each day 700,000 metric tons of pollutants are dumped into the atmosphere in the United States alone. B. Local Air Pollution 1.