Ecosystem Ecology

Ecology• “study of the interactions between the

organisms and their environment”

Biotic AbioticLiving

organismsNonliving organisms

Wildflower, animals, bacteria

Sunlight, precipitation, temperature,

soil, rock

Flow of Energy

• Photosynthesis a. Sun + 6 H2O + 6 CO2 C6H12O6 + 6 O2

b. performed by plants, algae, and some bacteria

http://www.phschool.com/science/biology_place/biocoach/photosynth/overview.html

• Cellular Respiration a. C6H12O6 + 6 O2 Energy + 6 H20 + 6 CO2

b. fuels own metabolism and growth c. aerobic v. anaerobic

http://bcs.whfreeman.com/friedlandapes/#t_668210____

Trophic Levels/Feeding Levels

Food Chain v. Food Web

http://bcs.whfreeman.com/friedlandapes/#t_668210____ (modified

http://bcs.whfreeman.com/friedlandapes/#t_668210____ (modified)

• Scavengers a. consume dead animals (vulture)

• Detritivores a. break down dead tissues and waste products into smaller particles (dung beetles)

• Decomposers a. complete the breakdown process by recycling the nutrients from dead tissues back into the ecosystem (fungi, bacteria)

•Gross Primary Productivity ex) total paycheck•Net Primary Productivity ex) paycheck after taxes

Energy Flow• Biomass: total mass of all living matter in an ecosystem• Energy is lost at each level (heat) a. 10% gained; 90% lost b. ecological efficiency

Matter Cycles Through the Biosphere

• Biosphere: combination of all ecosystems on Earth

• Biogeochemical Cycles: movements of matter within and between ecosystems that involved

biological, geological, and chemical processes

The Hydrologic Cycle

1. Evaporation2. Transpiration3. Infiltration4. Precipitation5. Condensation6. evapotranspiration7. Runoff

http://bcs.whfreeman.com/friedlandapes/#t_668210____

• Human Activities a. harvesting trees - decreased evapotranspiration, increased runoff b. construction

The Carbon Cycle1. Photosynthesis2. Respiration3. Exchange4. Sedimentation and burial5. Extraction6. Combustion

http://bcs.whfreeman.com/friedlandapes/#t_668210____

• Humans and the carbon cycle a. combustion of fossil fuels b. deforestation

The Nitrogen Cycle

• Nitrogen a. proteins and nucleic acids b. useable form nitrates and nitrites c. earth’s atmosphere 78% nitrogen gas d. most abundant element in the atmosphere

• Steps a. nitrogen fixation (nitrogen gas-N2) into ammonia-NH3) b. nitrification (ammonia to nitrites and nitrates) c. ammonification (decomposers) d. denitrification e. leaching

http://bcs.whfreeman.com/friedlandapes/#668210__690858__

Human affect

• Deforestation• Fertilizers• runoff

Phosphorous Cycle

• Major component of DNA, RNA and ATP

• Doesn’t exist in atmosphere a. limited to soil and H2O

• Steps a. weathering of phosphate rocks b. plants take up phosphate from soil and animals eat the plants c. decomposers release phosphate back in to soil d. animal excretion

Human Influence

• Fertilizers• Runoff into aquatic ecosystem a. excess growth of algae (algal bloom) resulting in hypoxia• Found in detergents

Calcium, Magnesium, Potassium and Sulfur

• Important in transmitting signal between cells

• Derived mostly from rocks and decomposed vegetation

• Calcium and Magnesium – limestone and marble

The Sulfur Cycle

• Similar to phosphorous cycle

• Important for proteins

• Found mainly in rocks and soil (coal, oil) as minerals

• Steps a. Weathering b. plants and animals relationship c. decomposers - sulfates convert to hydrogen sulfide gas which escapes into atmosphere, water, soil, marine sediments * result in acid rain

Human Influence

• Emissions from coal-burning power plants

Ecosystem Disturbances

• Disturbance: event caused by physical, chemical, or biological agents that results in changes in population size

a. natural and anthropogenic

• Understanding Biogeochemical Cycles a. helps in determining change by disturbance b. watershed studies - watershed: all of the land in a given landscape that drains into a stream, river, lake, or wetland

• Resistance v. Resilience a. resistance: measure of how much a

disturbance can affect the flows of energy and matter

b. resilience: rate at which an ecosystem can bounce back

• Intermediate Disturbance Hypothesis a. rare disturbances low diversity b. frequent disturbances low diversity c. intermediate disturbances highest diversity

Ecosystem Services

• Instrumental Value a. value in terms of how much economic benefit b. ecosystem services c. provisions

• Intrinsic Value a. moral value of an animal’s life