Carbon and energy flow through food webs. Which of the following statements correctly
describes how they flow through the ecosystems of our biosphere?
a. Carbon and energy remain in the system - continuously recycling. There is no new supply.
b. Carbon and energy continuously move through the system - in and out. There must be a
continuous new supply to replace the energy and carbon that is lost.
c. Carbon recycles through the system while energy moves through the system and must be replaced
with a continuous new supply from the sun.
d. Energy recycles through the system while carbon moves through the system and must be replaced
with a continuous new supply from the sun.
Answers
Key Points
Carbon, nitrogen, hydrogen, oxygen, phosphorus, and sulfur are conserved and recycled in the atmosphere, on land, in water, or beneath the earth’s surface.
Materials are recycled via erosion, weathering, water drainage, and the movement of tectonic plates.
Water is essential to all living processes, while carbon is found in all organic macromolecules.
Nitrogen and phosphorus are major components of nucleic acids and play major roles in agriculture.
Sulfur plays a role in the three-dimensional folding of proteins and is released into the atmosphere by the burning of fossil fuels.
Key Terms
hydrosphere: combined mass of water found on, under, and over the surface of a planet
biogeochemical cycle: cycling of mineral nutrients through ecosystems and through the non-living world