Biology Ecology 4 Part 2

Front 1

The Water Cycle

Back 1

- Biological Importance: Water is essential to all organisms.
- Forms available to life: Liquid water is the primary physical phase in which water is used, though some organisms can harvest water vapor.
- Reservoirs: Water is available in oceans, ice, and lakes, rivers, and groundwater.
- Key Process: The main processes driving the water cycle are evaporation of liquid water by solar energy, condensation of water vapor into clouds, and precipitation.

Front 2

The Carbon Cycle

Back 2

- Biological Importance: Carbon forms the framework of organic molecules essential to all life.
- Forms available to life: Photosynthetic organisms convert carbon in CO2 during photosynthesis to organic forms that are used by all other organisms.
- Reservoirs: The major reservoirs of carbon are fossil fuels, sediments, the oceans, and the atmosphere.
- Key Processes: Photosynthesis takes carbon from the atmosphere to turn in into organic compounds. Cellular respiration, volcanoes, and fossil fuels add carbon into the atmosphere.

Front 3

The Nitrogen Cycle

Back 3

- Biological Importance: Nitrogen is part of amino acids, proteins, and nucleic acids.
- Forms available to life: Animals = only use organic forms, bacteria = all forms, and plants = ammonium and nitrate as well as some organic forms.
- Reservoirs: The atmosphere, soils, and water are all reservoirs for nitrogen.
- Key Processes: The major pathway for nitrogen to enter is through nitrogen fixation by bacteria. Ammonification decomposes organic nitrogen to ammonium. In nitrification, ammonium is converted to nitrate. In denitrification, bacteria release N2.

Front 4

The Phosphorus Cycle

Back 4

- Biological Importance: Organisms require phosphorus as a major constitute of nucleic acids, phospholipids, and ATP.
- Forms available to life: Plants absorb phosphate and use it in the synthesis of organic compounds.
- Reservoirs: The largest accumulations of phosphorus are in sedimentary rocks of marine origin. There is also phosphorus in soils, the oceans, and in organisms.
- Key processes: Weathering of rocks adds PO4^3- to water and soil. Phosphate is taken up by producers and incorporated into biological molecules that may be eaten by consumers.

Front 5

Nitrogen fixation

Back 5

The conversion of N2 by bacteria into forms that can be used to synthesize nitrogenous organic compounds

Front 6

Ammonification

Back 6

Decomposes organic nitrogen to ammonium (NH4^+)

Front 7

Nitrification

Back 7

Ammonium (NH4^+) is converted to nitrate (NO3^-) by nitrifying bacteria

Front 8

Denitrification

Back 8

Denitrifying bacteria that use nitrate (NO3^-) in their metabolism and, instead of releasing O2, release N2