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Introduction to Environmental Science

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Introduction to Environmental Science

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Introduction to Environmental Science

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  1. Introduction to Environmental Science Chapters 1 and 2

  2. We Cannot Create or Destroy Matter • Law of conservation of matter – matter cannot be created nor destroyed • Matter is converted from one form to another Everything we think we have thrown away remains here with us in some form…

  3. Energy Changes Are Governed by Two Scientific Laws • First Law of Thermodynamics • Energy input always equals energy output • Second Law of Thermodynamics • Energy always goes from a more useful to a less useful form when it changes from one form to another • Decreased energy efficiency

  4. The Second Law of Thermodynamics in Living Systems

  5. Systems Respond to Change through Feedback Loops • Positive feedback loop - causes a system to change in the same direction

  6. Systems Respond to Change through Feedback Loops • Negative feedback loop – causes a system to change in the opposite direction from which it is moving • Opposing process • Can promote sustainability! • Aluminum mining  can  recycling

  7. Time Delays Can Allow a System to Reach a Tipping Point • Time delays vary • Between the input of a feedback stimulus and the response to it • Example: Planting trees • Tipping point, threshold level • Causes a shift in the behavior of a system

  8. System Effects Can Be Amplified through Synergy • Synergistic interaction – two or more processes interact so that the combined effect is greater than the sum of their separate effects • Helpful • E.g., campaign vs. individual persuasion • Harmful • E.g., Smoking and inhaling asbestos particles

  9. Ecology Chapters 3 and 4

  10. Habitat vs. Niche • Habitat – place where an organism lives • Organisms address • Niche – role of an organism in an ecosystem (physical, chemical, and biological conditions that a species needs to live and reproduce) • Organisms occupation • Thousands of organisms can occupy the same habitat but each organism has its own niche.

  11. Habitat vs. Niche

  12. Levels of Organization of Life • Organism- a living thing • Population- a group of organisms of the same species that live in a particular area • Community- populations of different species that live in one particular area

  13. Several Abiotic Factors Can Limit Population Growth • Limiting factor principle • Too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimal range of tolerance

  14. Range of Tolerance for a Population of Organisms • Range of tolerance may vary in populations • Small differences in genetic makeup, health, and age

  15. A Food Chain

  16. Ecological Efficiency • No organism EVER receives all of the energy from the organism it just ate • 10% Law • Only 10% of the energy from one trophic level is transferred to the next

  17. Some Ecosystems Produce Plant Matter Faster Than Others Do • Gross primary productivity (GPP) • Rate at which an ecosystem’s producers convert solar energy into chemical energy stored in their tissues • Net primary productivity (NPP) • Rate they create and store energy minus the energy they use for homeostasis • Ecosystems and life zones differ in their NPP NPP = GPP - R

  18. Nutrients Cycle in the Biosphere • Biogeochemical cycles, nutrient cycles • Nitrogen • Hydrologic • Carbon • Phosphorus • Sulfur • Connect past, present, and future forms of life

  19. Nitrogen Fixation • Nitrogen gas cannot be used by living things directly • Converted by lightening • Bacteria in soil and ocean convert nitrogen gas into ammonium (NH4+) and nitrates (NO3-) • Fixation

  20. Assimilation • Used by plants to produce amino acids, proteins, nucleic acids, and vitamins • When organism dies bacteria convert proteins into ammonia or ammonium • Ammonification

  21. Returning Nitrogen • Specialized bacteria in soil and bottom of lakes convert NH3 and NH4+ back into nitrates • Nitrification • Nitrates are converted to nitrogen gas and returned to the atmosphere • Denitrification • N2 • N2O

  22. Nitrogen Cycle Summary • Fixation • gas  ammonium or nitrate • Assimilation • Taken up by plants through roots; incorporated into proteins • Ammonification • Bacteria break down proteins into ammonia and ammonium • Nitrification • Ammonia  nitrates • Denitrification • nitrates  gas

  23. Human intervention in the nitrogen cycle • Additional NO and N2O • Burning fuels at high temperatures • Destruction of forest, grasslands, and wetlands • Add excess nitrates to bodies of water • Runoff • Remove nitrogen from topsoil • Harvesting nitrogen rich crops and irrigation

  24. Nitrogen Cycle in a Terrestrial Ecosystem with Major Harmful Human Impacts

  25. Hydrologic Cycle Including Harmful Impacts of Human Activities

  26. Alteration of the hydrologic cycle by humans • Withdrawal of large amounts of freshwater at rates faster than nature can replace it • Clearing vegetation • Increases temperature and thus evaporation • Increased flooding when wetlands are drained

  27. Carbon Cycle Equations Cellular Respiration C6H12O6  +  6O2  6CO2  +  6H2O +ATP  Photosynthesis 6CO2 + 6H2O sunlight C6H12O6 + 6O2

  28. Carbon Cycle • Marine sediments are earth’s largest store of carbon • Carbon is trapped between layers of sediment • Converted to fossil fuels when heated and compressed

  29. Natural Capital: Carbon Cycle with Major Harmful Impacts of Human Activities

  30. Phosphorous Cycle • Phosphorus • Helps form important molecules like DNA, RNA, and ATP • Inorganic phosphate PO43- is released into the soil and water as sediments wear down. • Eventually enters the ocean, where it is used by marine organisms • Does NOT include the atmosphere

  31. Phosphate Cycle • Organic phosphate moves through the food web and to the rest of the ecosystem. • Organisms • Land • Ocean • Sediments

  32. Phosphorus Cycle with Major Harmful Human Impacts

  33. Sulfur Cycles through the Biosphere • Sulfur found in organisms, ocean sediments, soil, rocks, and fossil fuels • SO2 in the atmosphere • H2SO4 and SO4- released during volcanic eruptions (toxic)

  34. Sulfur Cycles through the Biosphere • Human activities affect the sulfur cycle • Burn sulfur-containing coal and oil • Refine sulfur-containing petroleum to make gasoline and other heating products • Convert sulfur-containing metallic mineral ores • Copper lead and zinc

  35. Natural Capital: Sulfur Cycle with Major Harmful Impacts of Human Activities

  36. Evolution Chapter 5

  37. Individuals in Populations with Beneficial Genetic Traits Can Leave More Offspring • When environmental conditions change, populations • Adapt • Migrate • Become extinct • Genetic resistance – ability of one or more organisms in a population to tolerate a chemical designed to kill it • Malaria

  38. A group of bacteria, including genetically resistant ones, are exposed to an antibiotic Eventually the resistant strain replaces the strain affected by the antibiotic The genetically resistant bacteria start multiplying Most of the normal bacteria die Normal bacterium Resistant bacterium

  39. Geologic Processes Affect Natural Selection • Tectonic plates affect evolution and the location of life on earth • Location of continents and oceans • Species physically move, or adapt, or form new species through natural selection • Earthquakes • Volcanic eruptions

  40. Geographic Isolation Can Lead to Reproductive Isolation

  41. Extinction is Forever • Extinction • Endemic species • Species found only in one area • Particularly vulnerable • Golden Toad (Costa Rica) died out when habitat dried up

  42. Species Diversity: Variety, Abundance of Species in a Particular Place • Species diversity • Species richness – number of different species in a community • Species evenness – abundance of organisms within each type of species

  43. Species Diversity: Variety, Abundance of Species in a Particular Place • Most species-rich communities • Tropical rain forests • Coral reefs • Ocean bottom zone • Large tropical lakes

  44. Worldwide Richness? • Diversity varies with geographical location • Richness is highest at tropics • Lowest at the poles Question: Is productivity higher in a species-rich ecosystem?

  45. Each Species Plays a Unique Role in Its Ecosystem • Generalist species • Broad niche • Live in different places, eat different food, high range of tolerance • Examples? • Specialist species • Narrow niche • More prone to extinction • Examples?

  46. Specialist Species and Generalist Species Niches Question: Is better to be a generalist or a specialist?

  47. Niches Can Be Occupied by Native and Nonnative Species • Native species – organisms that normally live and thrive in a particular ecosystem • Nonnative species - invasive, alien, or exotic species • May spread rapidly • Not all are villains

  48. Indicator Species Serve as Biological Smoke Alarms • Indicator species – species that provide early warnings of damage to a community or ecosystem • Can monitor environmental quality • Trout • Birds • Butterflies • Frogs

  49. Coal Canaries: 1800s – 1900s • Coal miners took caged canaries into mines to act as early warning sentinels • If birds stopped singing and appeared to be distressed miners knew there were poisons being released

  50. Keystone, Foundation Species Determine Structure, Function of Their Ecosystems • Keystone species – have a large effect on the types and abundances of other species in an ecosystem • Pollinators • Top predator • Foundation species • Create or enhance their habitats, which benefit others • Elephants • Beavers