Lesson 6What cycles

occur in ecosystems?

niche of decomposers• recycle wastes & dead matter• ex:

• bacteria• fungi• earthworm• fly

Click for producers, consumers and decomposers game

decomposersbreak down

minerals& nutrients from deadorganisms

return minerals & nutrients

to soil (plants)

living thingseat plants decomposers

cycle

nitrogennitrogen• most abundant gas in most abundant gas in

atmosphere (78%)atmosphere (78%)

• sources of nitrogen:sources of nitrogen:

1.1. lightning- rainfalllightning- rainfall

2.2. some bacteriasome bacteria

3.3. fertilizersfertilizers

Some plants in tropical rainforests contain bacteria that

make nitrogen compounds.

• nitrogen in soil plants herbivores carnivores

oxygenoxygen• 22ndnd most most abundant gasabundant gas

• enters enters atmosphere by atmosphere by photosynthesisphotosynthesis

ways carbon dioxide

entersatmosphere

1. cellular

respiration

2.combustion

cellular respiration

• food + oxygen energy + CO2 + H20

combustioncombustion

• burning of a materialburning of a material