Presentation on theme: "Ecosystems Chapter 54. Ecosystem involves all abiotic and biotic factors in area. Trophic levels - groups in which organisms are placed according to eating."— Presentation transcript:
Detritivores - decomposers - break down detritus (dead organic matter left after organism dies) Organic matter must be recycled in ecosystem. Biggest decomposers - fungi and prokaryotes (secrete enzymes to break down dead material)
Gross primary productivity - amount of light energy converted to chemical energy. Net primary productivity - gross productivity minus amount of energy used by primary producers for respiration (amount of energy left over)
Nutrients also contribute to biomass in aquatic areas. Nitrogen - plant growth (can be limited in water) Water pollution adds nutrients to water (eutrophication) Shifts organisms living in water and is a negative impact of humans.
Product of nitrogen fixation is ammonia. Ammonia picks up H + in soil to become ammonium (ammonification) Plants can use this nitrogen. Aerobic bacteria can turn ammonium into a nitrate (nitrification)
Humans affect rate of chemical cycling due to habits. Farmers - disturb crop areas by removing nutrients in soil. Humans - add fertilizers to soil which disrupt chemical balances. Chemicals can enter water, disrupting animals that live there.