Anchor BIO.B.4.2 Describe interactions andrelationships in an ecosystem

BIO.B.4.2.3 Describe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle).

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Unlike one-way flow of energy (which is eventually lost as heat), matter is recycled within and between ecosystems

The four key cycles critical to all ecosystems are:

• Water (all living things need H2O)• Nitrogen (Proteins)• Carbon (Proteins, Carbohydrates, Lipids, DNA/RNA)• Phosphorous (ATP, DNA / RNA)

Water (H2O) Cycle

Water (H2O) Cycle

Atmosphere Ecosystem

• Condensation of water vapor (clouds) causes a return to surface by precipitation (rain/snow)

• Distributed by run-off, seepage and soil percolation

Recycled back to Atmosphere

• Enters atmosphere by evaporation or transpiration thru plants (via photosynthesis)

Carbon Cycle

CO2

C6 H12O6

CO2

CO2

CO2

Carbon (C) CycleAtmosphere Ecosystem

• Photosynthetic autotrophs capture & convert CO2 into carbohydrates (C6H12O6)

• Distributed throughout food web

• May be stored for long periods in dead organic matter (fossil fuels)

Recycled back to Atmosphere

• As carbs are “broken down” for energy via Cellular Respiration, CO2 is released into air

• Combustion (wood/fossil fuels) & volcanoes also release huge amts of CO2 ……(as per Al Gore)

Nitrogen Cycle

N2

N2

NH3

NH3 NH3

Proteins

denitrification

Nitrogen (N) CycleAtmosphere Ecosystem

• Nitrogen fixing bacteria --live w/in certain plant roots that convert N2 into usable nitrates/ ammonia) NOTE: Lightening also converts N2 NH3

• Uptake by plants (from soil/water) & distributed throughout food web

• Used to make proteins—when organisms dies, decomposers returns to Nutrient Pool for producers --(cycles within ecosystem)

Recycled back to Atmosphere• Denitrifying bacteria converts some of the soil

ammonia back into N2 gas

Phosphorus Cycle

erosion

decomposition seashells

Phosphorous (P) Cycle

Atmosphere Ecosystem

• Does not ever enter the atmosphere

Cycles throughout Ecosystem --(very slowly)

• Rocks/ sediments slowly erode and release into soil/water

• Decomposers also release back into nutrient pool (soil/water)

• Uptake by plants (from soil/water) & distributed throughout food web

Primary Succession begins with pioneer species (mosses and

lichens) growing on land surfaces where no soil exists such as new oceanic islands from volcanoes or glacier activity

Secondary Succession begins when events which leave the soil, such as fires, logging and farming stop and new communities are allowed to colonize an area undisturbed. In time the ecosystem will return to its original, sustainable condition (climax community).

Species accidentally or intentionally introduced into the ecosystem compete with native species for habitat.

Invasive species reproduce rapidly because their new habitat lacks the limiting factors (i.e. predators) that would normally control their population.

Anchor BIO.B.4.2 Describe interactions andrelationships in an ecosystem

BIO.B.4.2.5 Describe the effects of limiting factors on population dynamics and potential species extinction.

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Density-dependent limiting factors include competition, predation, parasitism and disease. Density-dependant limiting factors are most active on large, dense populations.

Density-Independent limiting factors include weather, natural disasters, seasonal cycles and human activities (damming rivers or clear-cutting forests). The size of the population is not important.

I’ll bet the endangered mountain goat population is now extinct!