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50 lectures ppt

  1. 1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsPowerPoint Lectures forBiology, Seventh EditionNeil Campbell and Jane ReeceLectures by Chris RomeroChapter 50An Introduction to Ecologyand the Biosphere
  2. 2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsOverview: Discovering Ecology• Ecology is the scientific study of the interactionsbetween organisms and the environment• These interactions determine distribution oforganisms and their abundance• Modern ecology includes observation andexperimentation© 2011 Pearson Education, Inc.
  3. 3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.2Global ecologyLandscape ecologyEcosystem ecologyCommunity ecologyPopulation ecologyOrganismal ecology
  4. 4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsGlobal Ecology• The biosphere is the global ecosystem, the sumof all the planet’s ecosystems• Global ecology examines the influence ofenergy and materials on organisms across thebiosphere© 2011 Pearson Education, Inc.
  5. 5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsLandscape Ecology• A landscape or seascape is a mosaic ofconnected ecosystems• Landscape ecology focuses on the exchangesof energy, materials, and organisms acrossmultiple ecosystems© 2011 Pearson Education, Inc.
  6. 6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.2bLandscape ecology
  7. 7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsEcosystem Ecology• An ecosystem is the community of organismsin an area and the physical factors with whichthey interact• Ecosystem ecology emphasizes energy flowand chemical cycling among the various bioticand abiotic components© 2011 Pearson Education, Inc.
  8. 8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.2cEcosystem ecology
  9. 9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsCommunity Ecology• A community is a group of populations ofdifferent species in an area• Community ecology deals with the whole arrayof interacting species in a community© 2011 Pearson Education, Inc.
  10. 10. LE 50-3cCommunity ecology
  11. 11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsPopulation Ecology• A population is a group of individuals of thesame species living in an area• Population ecology focuses on factorsaffecting population size over time© 2011 Pearson Education, Inc.
  12. 12. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.2ePopulation ecology
  13. 13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsOrganismal Ecology• Organismal ecology studies how an organism’sstructure, physiology, and (for animals) behaviormeet environmental challenges• Organismal ecology includes physiological,evolutionary, and behavioral ecology© 2011 Pearson Education, Inc.
  14. 14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.2fOrganismal ecology
  15. 15. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsEarth’s climate varies by latitude and season and ischanging rapidly• The long-term prevailing weather conditions in anarea constitute its climate• Four major abiotic components of climate aretemperature, precipitation, sunlight, and wind• Macroclimate consists of patterns on the global,regional, and landscape level• Microclimate consists of very fine patterns, suchas those encountered by the community oforganisms underneath a fallen log© 2011 Pearson Education, Inc.
  16. 16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsGlobal Climate Patterns• Global climate patterns are determined largelyby solar energy and the planet’s movement inspace• The warming effect of the sun causestemperature variations, which drive evaporationand the circulation of air and water• This causes latitudinal variations in climate© 2011 Pearson Education, Inc.
  17. 17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsLatitudinal Variation in Sunlight Intensity• The angle at which sunlight hits Earth affects itsintensity, the amount of heat and light per unit ofsurface area• The intensity of sunlight it strongest in thetropics (between 23.5° north latitude and 23.5°south latitude)© 2011 Pearson Education, Inc.
  18. 18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.3aLatitudinal variation in sunlight intensity90°N (North Pole)60°N30°N23.5°N (Tropic ofCancer60°S90°S (South Pole)0° (Equator)23.5°S (Tropic ofCapricorn)30°SLow angle of incoming sunlightAtmosphereSun overhead at equinoxesLow angle of incoming sunlight
  19. 19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsGlobal Air Circulation and PrecipitationPatterns© 2011 Pearson Education, Inc.• Global air circulation and precipitation patternsplay major roles in determining climate patterns• Water evaporates in the tropics, and warm wet airmasses flow from the tropics toward the poles
  20. 20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings• Rising air masses release water and cause highprecipitation, especially in the tropics• Dry, descending air masses create arid climates,especially near 30°• Air flowing close to Earth’s surface createspredictable global wind patterns• Cooling trade winds blow from east to west in thetropics; prevailing westerlies blow from west toeast in the temperate zones© 2011 Pearson Education, Inc.
  21. 21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.3bGlobal air circulation and precipitation patternsWesterliesNortheast tradesSoutheast tradesWesterlies30°N0°ARIDZONE66.5°N (Arctic Circle)30°N0°30°S60°N60°S66.5°S (Antarctic Circle)Descendingdry airabsorbsmoisture.Ascendingmoist airreleasesmoisture.
  22. 22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsRegional and Local Effects on Climate• Climate is affected by seasonality, large bodiesof water, and mountains© 2011 Pearson Education, Inc.
  23. 23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsSeasonality• Seasonal variations of light and temperatureincrease steadily toward the poles• Seasonality at high latitudes is caused by the tiltof Earth’s axis of rotation and its annual passagearound the sun• Belts of wet and dry air straddling the equatorshift throughout the year with the changing angleof the sun• Changing wind patterns affect ocean currents© 2011 Pearson Education, Inc.
  24. 24. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.4March equinoxDecembersolsticeSeptember equinox60°N30°S30°N0° (equator)Constant tiltof 23.5°June solstice
  25. 25. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsBodies of Water• Oceans, their currents, and large lakesmoderate the climate of nearby terrestrialenvironments• The Gulf Stream carries warm water from theequator to the North Atlantic© 2011 Pearson Education, Inc.
  26. 26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.5IndianOceanSubtropicalGyreCalifornia Current30°N North PacificSubtropical Gyre30°SEquatorSouth PacificSubtropical GyreLabrador CurrentGulf StreamNorth AtlanticSubtropicalGyreSouthAtlanticSubtropicalGyreAntarctic Circumpolar Current
  27. 27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings• During the day, air rises over warm land anddraws a cool breeze from the water across theland• As the land cools at night, air rises over thewarmer water and draws cooler air from landback over the water, which is replaced by warmair from offshore© 2011 Pearson Education, Inc.
  28. 28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsMountains• Rising air releases moisture on the windwardside of a peak and creates a “rain shadow” as itabsorbs moisture on the leeward side• Mountains affect the amount of sunlight reachingan area• In the Northern Hemisphere, south-facing slopesreceive more sunlight than north-facing slopes• Every 1,000 m increase in elevation produces atemperature drop of approximately 6°C© 2011 Pearson Education, Inc.
  29. 29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.6Air flowOceanMountainrangeLeeward sideof mountains
  30. 30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsInteractions between organisms and theenvironment limit the distribution of species• Species distributions are the result of ecologicaland evolutionary interactions through time• Evolutionary time spans many generations andcaptures adaptation through natural selection• For example, Galápagos finches with largerbreaks were more likely to survive a drought asthey could eat the available larger seeds• As a result, the average beak size was larger inthe next generation© 2011 Pearson Education, Inc.
  31. 31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings• Both biotic and abiotic factors influence speciesdistribution– For example, climate, interspecific interactions,and other factors affect the distribution of thered kangaroo© 2011 Pearson Education, Inc.
  32. 32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsKangaroos/km20–0.10.1–11–55–1010–20> 20Limits ofdistributionFigure 52.17
  33. 33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsBehavior and Habitat Selection• Some organisms do not occupy all of theirpotential range• Species distribution may be limited by habitatselection behavior© 2011 Pearson Education, Inc.
  34. 34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsBiotic Factors• Biotic factors that affect the distribution oforganisms may include– Predation– Herbivory• For example, sea urchins can limit thedistribution of seaweeds– Competition© 2011 Pearson Education, Inc.
  35. 35. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsBoth limpets and urchinsremovedOnly urchinsremovedRESULTSSeaweedcover(%)Only limpets removedControl (both urchinsand limpets present)Sea urchinLimpet100806040200February1983August1983August1982February1984Figure 52.20
  36. 36. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsAbiotic Factors• Abiotic factors affecting distribution of organismsinclude– Temperature– Water– Sunlight– Wind– Rocks and soil• Most abiotic factors vary in space and time© 2011 Pearson Education, Inc.
  37. 37. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsTemperature• Environmental temperature is an important factorin distribution of organisms because of its effectson biological processes• Cells may freeze and rupture below 0°C, whilemost proteins denature above 45°C• Mammals and birds expend energy to regulatetheir internal temperature© 2011 Pearson Education, Inc.
  38. 38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsWater and Oxygen• Water availability in habitats is another importantfactor in species distribution• Desert organisms exhibit adaptations for waterconservation• Water affects oxygen availability as oxygendiffuses slowly in water• Oxygen concentrations can be low in deepoceans and deep lakes© 2011 Pearson Education, Inc.
  39. 39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsSalinity• Salt concentration affects water balance oforganisms through osmosis• Most aquatic organisms are restricted toeither freshwater or saltwater habitats• Few terrestrial organisms are adapted to high-salinity habitats© 2011 Pearson Education, Inc.
  40. 40. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsSunlight• Light intensity and quality (wavelength) affectphotosynthesis• Water absorbs light, thus in aquaticenvironments most photosynthesis occurs nearthe surface• In deserts, high light levels increase temperatureand can stress plants and animals© 2011 Pearson Education, Inc.
  41. 41. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsFigure 52.21Organisms at high elevation are exposed to high UV radiation, freezing temperatures,moisture deficits, and strong winds that restrict the growth and survival of trees.
  42. 42. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsRocks and Soil• Many characteristics of soil limit distribution ofplants and thus the animals that feed on them– Physical structure– pH– Mineral composition© 2011 Pearson Education, Inc.
  43. 43. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin CummingsWhy is species X absent from an area?Does dispersal limit its distribution?Does behavior limit its distribution?Do biotic factors (other species)limit its distribution?Do abiotic factors limitits distribution?NoNoNoYesYesYesPhysicalfactorsChemicalfactorsArea inaccessible orinsufficient timeHabitat selectionPredation, parasitism,competition, diseaseTemperature, light, soilstructure, fire, moisture,etc.Water, oxygen, salinity,pH, soil nutrients, etc.Figure 52.UN01

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