Energy Flows and Matter Cycles

1. EK 4.A.6 Interactions among living systems & with their environment result in the movement of matter & energy Energy Flows and Matter Cycles

2. Energy Flows through Trophic Levels • Primary Producers – autotrophs capable of converting solar energy into chemical energy (plants, photosynthetic protists, cyanobacteria and chemosynthetic bacteria

3. Energy Flows through Trophic Levels • Primary Consumers – herbivores that eat primary producers • Secondary consumers – primary carnivores that eat primary consumers • Tertiary consumers – secondary carnivores eat the secondary consumers

4. Energy Flower through Trophic Levels • Detritivores – consumers that obtain their energy by consuming dead plants and animals (detritus); the smallest are called decomposers and include fungi and bacteria; others include nematodes, earthworms insects and scavengers such as crabs, vultures, and jackals

5. Energy Flows through Trophic Levels • Ecological Pyramids – used to show the relationship between the tropic levels; Horizontal bars or tiers are used to represent the relative size of the tropic levels, each represented in terms of energy (productivity), biomass or numbers of organisms; tiers are stacked upon one another in the order in which energy is transferred

6. Energy Flow through Trophic Levels • Ecological Efficiency – describes the proportion of energy represented at one trophic level that is transferred to the next level; only about 10% of the productivity (energy) of one trophic levels is transferred to the next level; 90% of the energy is consumed by the individual metabolic activities of the organism

7. Energy Flows through Trophic Levels • Food Chain – linear flow chart of who eats whom; shows energy flow • Food Web – expanded, more complete version of food chain; Arrows connect all organisms that are eaten to the animals that eat them in the direction of the energy flow

8. Matter is Recycled • Biogeochemical Cycles – describe the flow of essential elements from the environment to living things and back to the environment • Why do we need these elements to be recycled? What purpose do they serve?

9. Matter is Recycle • Hydrological cycle • Reservoirs – oceans, air (as water vapor), groundwater, glaciers, (evaporation, wind and percipitation move water from oceans to lands • Assimilation – plants absorb water from the soil animals drink water or eat other organisms (which are mostly water) • Release – plants transpire; animals and plants decompose

10. Matter is Recycle • Carbon Cycle • Reservoirs – atmosphere (as CO2), fossil fuels (coal and oil), peat, durable organic material (i.e. cellulose) • Assimilation – plants use CO2 in photosynthesis; animals consume plants or other animals • Release – plants and animals release CO2 through respiration and decomposition; CO2 is released when organic material is burned

11. Matter is Recycled • Nitrogen Cycle • Reservoirs – atmosphere (N2); soil (NH4 ammonium, NH3 ammonia, NO2 nitrite, or NO3 nitrate) • Assimilation – plants absorb nitrogen either as nitrate or ammonium; animals obtain nitrogen by eating plants or other animals

12. Matter is Recycled • Nitrogen Assimilation • Nitrogen Fixation – Nitrogen gas and ammonium are fixed by nitrogen-fixing prokaryotes (in soil or root nodules); nitrogen gas is converted to ammonia by lightening and UV radiation

13. Matter is Recycled • Nitrogen Assimilation • Nitrification – ammonium converted to nitrite and nitrite converted to nitrate by various nitrifying bacteria; ammonium or nitrate converted to organic compounds by plant metabolism

14. Matter is Recycle • Nitrogen Cycle • Release – denitrifying bacteria convert nitrate back to nitrogen gas (denitrification); detrivorous bacteria convert organic compounds back to ammonium (ammonification); animals excrete ammonium or ammonia, urea or uric acid

15. Matter is Recycled • Phosphorus Cycle • Reservoirs – rocks and ocean sediments • Assimilation – plants absorb inorganic phosphate from soils; animals obtain organic phosphorous when then eat plants or other animals • Release – plants and animals release phosphorous when they decompose; animals excrete phosphorous in their waste products