course, the flowing water causes erosion to the land in the river’s new path. Phosphorus within the eroded land is released and enters the water phase of the phosphorus cycle. Disruptions Caused by HumansHuman actions disrupt both biogeochemical cycles and ecosystems. As the human population grows, so do our needs. Agriculture is responsible for growing most of the foods that humans eat and many products needed for many industries. But poor farming practices cause disruptions to the cycles. Chapter13:Principles of Ecology409
(tl) ©Muralidharan Alagar Arts and Photography/Getty Images; (tc) ©Justin Lambert/Image Bank/Getty Images; (tr) ©Emmanuel LATTES/Alamy ImagesSELF-CHECK OnlineHMDScience.comGO ONLINEFormative AssessmentREVIEWING MAIN IDEAS 1. How does the hydrologic cyclemove water through the environment? 2. Describe a human activity that disrupts the carbon cycle and the consequences of that disruption. 3. Summarize How can microorgan-isms, such as some green algae, affect the health of organisms in aquatic ecosystems? 11C 4. Synthesize Explain the importance of decomposers to the overall 5. How might Earth’s biogeo-chemical cycles help scien-tists to understand the early history of life on Earth?