Module 1.2: Ecosystems

prelim topic

Atmosphere

• Composed of the troposphere and the stratosphere

Hydrosphere

• The water at or near the earth’s surface (ice, water, and water vapor)

Geosphere

• Composed of a hot core, a thick, mostly rocky mantle and a thin outer crust

Biosphere

• Wherever life is found within the other three spheres

Atmosphere, Hydrosphere, Geosphere, Biosphere

The Earth’s 4 major component of its life-support system

Organisms

• They produce their own nutrition

• Satisfy nutritional requirements by consuming other organisms

• Decompose waste and remains of organisms thereby recycling nutrients

Ecology

• Is how organisms interact with each other and with their non-living environment

Autotrophs

• These organisms are producers; use photosynthesis to make nutrients

• Plants

Heterotrophs

• These organisms are consumers who feed on other organisms or their remains

• Herbivores, carnivores, omnivores

Food Chains

• A sequence of organisms, each of which serves as a nutritional source for the next (big fish eat smaller fish)

Food webs

• A complex network of interconnected food chains

GPP (gross primary productivity)

• The rate that an ecosystem’s producers convert energy into biomass

NPP (net primary productivity)

• The rate that producers use photosynthesis to produce and store chemical energy minus the rate at which they use energy for aerobic respiration

Biogeochemical cycling

• the natural pathway by which essential elements of living matter—such as carbon, nitrogen, and water—move between the living (biotic) and non-living (abiotic) parts of the Earth.

• Because Earth is a closed system with a limited amount of matter, these cycles ensure that nutrients are constantly reused and recycled to sustain life.

Hydrologic Cycle

(Biogeochemical cycling)

• This cycle collects, purifies, and distributes the earth’s fixed supply of water

• Incoming solar radiation moves water at the surface into the atmosphere through evaporation

• Condensation in the atmosphere and effects of gravity create precipitation which returns water to the earth’s surface

• Only a very small portion of earth’s water is fresh water

Carbon Cycle

(Biogeochemical cycling)

• Refers to the cycle of atmospheric carbon dioxide = a key component of this cycle, has a significant temperature effect (greenhouse effect)

• This cycle through the biosphere by: photosynthesis by producers, aerobic respiration by producers, consumers, and decomposers.

Nitrogen Cycle

(Biogeochemical cycling)

• This cycle through the biosphere by:

• Bacteria converting nitrogen into a usable form so it becomes a useful plant nutrient

• Consumers (herbivores) and decomposers convert nitrogen back into nitrogen gas which is then released into the atmosphere.

TRUE

• Atmospheric nitrogen CANNOT be absorbed or used directly by most organisms

Phosphorus Cycle

(Biogeochemical cycling)

• This cycle through the biosphere by:

• Cycle through soils, rocks, water and plants, but not through the atmosphere

• Can be temporarily removed from natural cycling when washed into oceans and trapped in marine sediments

• As with nitrogen, it contributes to agricultural runoff

Sulfur Cycle

(Biogeochemical cycling)

• This cycle through the biosphere by:

• Via mining of ore deposits/ocean sediments

• From active volcanoes - as poisonous hydrogen sulfide and sulfur dioxide gases

• Through the decomposition of organic matter in wetlands

• From sea spray, dust storms, and forest fires

• Absorption by plant roots