1. Ecosystems and Human Interferences
Chapter 48
Assignment # 23
Mader: Biology 8th Ed.

2. Biogeochemical Cycles Hydrologic Cycle Carbon Cycle Nitrogen Cycle
Outline
Biotic Components
Autotrophs
Heterotrophs
Energy Flow
Ecological Pyramids
Biogeochemical Cycles
Hydrologic Cycle
Carbon Cycle
Nitrogen Cycle
Phosphorus Cycle
Mader: Biology 8th Ed.

3. An ecosystem where organisms interact. Ecosystems characterized by:
Nature of Ecosystems
Biosphere is part of the atmosphere, hydrosphere, and lithosphere that contains living organisms.
An ecosystem where organisms interact.
Ecosystems characterized by:
One-Way flow of energy.
Cycle of materials from abiotic environment through biotic community.
Mader: Biology 8th Ed.

4. Biotic Components Autotrophs
Require only inorganic nutrients and an outside energy source to produce organic nutrients.
Producers
Photoautotrophs
Chemoautrophs.
Mader: Biology 8th Ed.

5. Heterotrophs need a preformed source of organic nutrients. Consumers
Herbivores - Feed on plants.
Carnivores - Feed on other animals.
Omnivores - Feed on plants and animals.
Decomposers are heterotrophic bacteria and fungi that break down dead organic matter.
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6. Biotic Components
Mader: Biology 8th Ed.

7. Energy Flow and Chemical Cycling
Energy flow occurs because as nutrients pass from one population to another, all the energy content is converted to heat, which dissipates into the environment.
Chemicals cycle as organic nutrients are returned to the producers.
Excretion
Death
Cellular Respiration
Mader: Biology 8th Ed.

8. Energy Balances
Mader: Biology 8th Ed.

9. Energy Flow
Food Web - Interconnecting paths of energy flow describing trophic relationships.
Mader: Biology 8th Ed.

10. Explains why few carnivores can be supported in a food web.
Ecological Pyramids
A trophic level is composed of all the organisms that feed at a particular link in a food chain.
In general, only about 10% of the energy of one trophic level is available to the next trophic level.
Explains why few carnivores can be supported in a food web.
Mader: Biology 8th Ed.

11. Ecological Pyramid
Mader: Biology 8th Ed.

12. Global Biogeochemical Cycles
Chemical cycling may involve:
Reservoir - Source normally unavailable to producers.
Fossil Fuels - Minerals - Sediments
Exchange Pool - Source from which organisms generally take chemicals.
Atmosphere - Soil - Water
Biotic Community - Chemicals move along food chains, perhaps never entering a pool.
Mader: Biology 8th Ed.

13. Fresh water evaporates from bodies of water.
Hydrologic Cycle
Fresh water evaporates from bodies of water.
Precipitation on land enters the ground, surface waters, or aquifers.
Water eventually returns to the oceans.
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14. Hydrologic Cycle
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15. Atmosphere is an exchange pool for carbon dioxide.
Carbon Cycle
Atmosphere is an exchange pool for carbon dioxide.
Fossil fuel combustion has increased the total amount of carbon dioxide in the atmosphere.
Transfer Rate
Mader: Biology 8th Ed.

16. Carbon Cycle
Mader: Biology 8th Ed.

17. Carbon dioxide, nitrous oxide, methane
Greenhouse Effect
Greenhouse gases allow solar radiation to pass through atmosphere but trap heat (infrared radiation) from escaping.
Carbon dioxide, nitrous oxide, methane
If Earth’s temperature rises, more water will evaporate, forming more clouds and setting up a potential positive feedback loop.
Mader: Biology 8th Ed.

18. Earth’s Radiation Balances
Mader: Biology 8th Ed.

19. Nodules on legume roots. Nitrification - Production of nitrates.
Nitrogen Cycle
Atmospheric nitrogen is fixed by bacteria in order to make it available to plants.
Nodules on legume roots.
Nitrification - Production of nitrates.
Denitrification - Conversion of nitrate to nitrous oxide and nitrogen gas.
Balances nitrogen fixation.
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20. The Nitrogen Cycle
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21. Nitrogen and Air Pollution
Acid Deposition
Nitrogen oxides and sulfur dioxide are converted to acids when they combine with water vapor.
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22. Thermal Inversion
Mader: Biology 8th Ed.

23. Phosphorus does not enter the atmosphere. Sedimentary cycle.
Phosphorus Cycle
Phosphorus does not enter the atmosphere.
Sedimentary cycle.
Phosphate taken up by producers incorporated into a variety of organic molecules.
Can lead to water eutrophication.
Biomagnification
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24. Phosphorus Cycle
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25. Sources of Water Pollution
Mader: Biology 8th Ed.

26. Biogeochemical Cycles Hydrologic Cycle Carbon Cycle Nitrogen Cycle
Review
Biotic Components
Autotrophs
Heterotrophs
Energy Flow
Ecological Pyramids
Biogeochemical Cycles
Hydrologic Cycle
Carbon Cycle
Nitrogen Cycle
Phosphorus Cycle
Mader: Biology 8th Ed.

27. Mader: Biology 8th Ed.