What is the key concept for this section? What happens to matter in an ecosystem? What is a nutrient cycle? Explain how nutrient cycles connect past, present, and future life. Describe the hydrologic...

What is the key concept for this section? What happens to matter in an ecosystem? What is a nutrient cycle? Explain how nutrient cycles connect past, present, and future life. Describe the hydrologic cycle, or water cycle. What three major processes are involved in the water cycle? What is surface runoff? Define groundwater. What is an aquifer? What percentage of the earth’s water supply is available to humans and other species as liquid freshwater? Summarize the unique properties of water. List three ways that humans are altering the water cycle. Explain how clearing a rain forest can affect local weather and climate.