Environmental Cycles

While energy flows through the ecosystem in one direction (producers to consumers to higher consumers), matter cycles back through the ecosystem in a continuous loop.

Most elements have an abiotic (non-living) reservoir where they are stored in the environment
They also move through living organisms
Remember, organic molecules are mostly made of the elements C, H, O, N, and P. Obtaining these elements is critical to survival.
When cycles are disrupted by human activities, they can cause too much of the matter in some places and too little in other places.

Water Cycle

Water covers 70% of the earth but most of it is too salty to be used by land organisms.

Reservoirs are bodies of water (ocean, lakes, rivers etc.)
Water has many properties that are useful to living things
Every organic molecule in the body has Hydrogen and Oxygen

Carbon Cycle

Carbon, with its 4 covalent bonds, is the element that allows organic molecules to be so complex.

Reservoirs include the atmosphere (CO2), soil and some rock
Carbon frequently moves between molecules of glucose and carbon dioxide during photosynthesis and respiration
Every organic molecule has carbon

Nitrogen Cycle

Nitrogen is crucial for making proteins which determine the traits of an organism.

Nitrogen gas (N2)makes up 80% of the air around us(main reservoir)
- It can only be used by a few types of bacteria
It is crucial for making proteins and nucleic acids