1. Ecosystem Ecology
Chapter 3

2. Ecology
“study of the interactions between the organisms and their environment”

3. Wildflower, animals, bacteria
Biotic
Abiotic
Living organisms
Nonliving organisms
Wildflower, animals, bacteria
Sunlight, precipitation, temperature, soil, rock

4. Flow of Energy Photosynthesis a. Sun + 6 H2O + 6 CO2  C6H12O6 + 6 O2
b. performed by plants, algae, and some bacteria
To understand how ecosystems function and how to best protect and manage them, ecologists study the processes that move matter and energy through them.

5. Cellular Respiration a. C6H12O6 + 6 O2 Energy + 6 H20 + 6 CO2
b. fuels own metabolism and growth
c. aerobic v. anaerobic

6. Trophic Levels/Feeding Levels

7. Food Chain v. Food Web
(modified
(modified)

8. a. consume dead animals (vulture) Detritivores
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)
Not all organisms fit neatly into a single trophic level.
Each level produces dead individuals and waste products that feed other organisms.

9. Gross Primary Productivity ex) total paycheck Net Primary Productivity
ex) paycheck after taxes
GPP: total amount of solar energy that the producers in an ecosystem capture via photosynthesis over a given amount of time
NPP: total amount after the producers have respired

10. 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
The NPP establishes the rate at which biomass is produced over a given amount of time
Not all energy at each trophic level is in usable form
Standing crop: amount of biomass present at a particular time

11. 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
Biosphere: where life is found
Remind that earth is an open system for energy and a closed system for matter
All of earth’s organisms are composed mostly of carbon, hydrogen, nitrogen, oxygen and phosphorus.

12. The Hydrologic Cycle Evaporation Transpiration Infiltration
Precipitation
Condensation
evapotranspiration
Runoff
Evapotranspiration: combination of water evaporation through evaporation and transpiration; used to measure the amount of water moving through an ecosystem

13. - decreased evapotranspiration, increased runoff b. construction
Human Activities
a. harvesting trees
- decreased evapotranspiration, increased
runoff
b. construction
Earth is closed to matter therefore water never leaves it.
Harvesting trees: decreases evapotranspiration from decreasing plant biomass

14. The Carbon Cycle Photosynthesis Respiration Exchange
Sedimentation and burial
Extraction
Combustion
Carbon is the most important element in organisms making up approx 20% of their total body weight
Exchange: occurs between ocean and atmosphere
* amount of CO2 released from the ocean into the atmosphere equals the amount of atmospheric CO2 that diffuses into the ocean water
Sedimentation and burial
Dissolved CO2 in ocean combines with the calcium ions in the water to form calcium carbonate (can precipitate out of water and form limestone)
Small amounts of organic carbon is buried into sediments and becomes fossilized but later can turned into fossil fuels
Extaction
Extraction of fossil fuels (doesn’t alter the carbon cycle)
Combustion
Releases carbone into the atmosphere or into the soil as ash

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

16. 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

17. a. nitrogen fixation (nitrogen gas-N2) into ammonia-NH3)
Steps
a. nitrogen fixation (nitrogen gas-N2) into
ammonia-NH3)
b. nitrification (ammonia to nitrites and nitrates)
c. ammonification (decomposers)
d. denitrification
e. leaching
Nitrate is carried to the earth’s surface through precipitation
Ammonification – fungal and bacterial decomposers use the nitrogen-containing wastes and dead bodies as a food source and excrete ammonia
Leaching: nitrate ions do not easily bind to soil particles therefore it is transported through the soil with water
Denitrification: nitrates that have settled on the bottom of the ocean or in waterlogged soils, denitrifying bacteria convert nitrate into nitrous oxide and then eventually N2 is emitted into the atmosphere

18. Human affect
Deforestation
Fertilizers
runoff

19. Phosphorous Cycle Major component of DNA, RNA and ATP
Doesn’t exist in atmosphere
a. limited to soil and H2O
Has no gaseous component therefore atmospheric inputs are very small
Found in:
Precipitates out of sediments on the ocean floor or in the weathering of rocks

20. 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

21. Human Influence Fertilizers Runoff into aquatic ecosystem
a. excess growth of algae (algal bloom)
resulting in hypoxia
Found in detergents
Excessive algael growth, they eventually die intiating a massive amount of decomposition with consumes lots of oxygen
Hypoxia – low oxygen with in turns kills fish and other animals

22. Calcium, Magnesium, Potassium and Sulfur
Important in transmitting signal between cells
Derived mostly from rocks and decomposed vegetation
Calcium and Magnesium – limestone and marble

23. The Sulfur Cycle Similar to phosphorous cycle Important for proteins
Found mainly in rocks and soil (coal, oil) as minerals

24. 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

25. Human Influence
Emissions from coal-burning power plants

26. Ecosystem Disturbances
Disturbance: event caused by physical, chemical, or biological agents that results in changes in population size
a. natural and anthropogenic
Natural: hurricanes, volcanic eruptions, forest fires
Anthropogenic: air pollution, agriculture
Ecologists are interested in whether an ecosystem can resist the impact of a disturbace and whether it can recover its original condition (resistance and resilience)

27. 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

28. 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
Not every disturbances is a disaster. Example: low-intensity fire
Resistance: when a disturbance influences populations and communities but has not effect on overall flow of energy and matter (HIGH RESISTANCE)
Resilience
* High – can return back to original within a year

29. Intermediate Disturbance Hypothesis
a. rare disturbances  low diversity
b. frequent disturbances  low diversity
c. intermediate disturbances  highest diversity
Rare disturbances
Intense competition among species therefore populations of highly competitive species survive
Frequent disturbances
Eliminates most species except for those that have evolved to live under those conditions
Intermediate
Species from both extremes can survive

30. 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
Instrumental
It has worth as an instrument or tool
Ecosystem services: benefits that humans can obtain from natural ecosystems
Provisions: goods that humans can directly use (lumber, food crops)
Intrinsic
* Has worth independent of any benefit it may provide to humans