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  1. 1. Chapter 10: Cycles andPatterns in the BiosphereMcKnight’s Physical Geography:A Landscape Appreciation,Tenth Edition, Hess
  2. 2. Cycles and Patterns in theBiosphere• The Impact of Plants and Animals on theLandscape• The Geographic Approach to the Study ofOrganisms• Biogeochemical Cycles• Food Chains• Natural Distributions• Environmental Relationships2© 2011 Pearson Education, Inc.
  3. 3. The Impact of Plants and Animalson the Landscape• Vegetation grew profuselyat one time• Human modification ofvegetation• Animal life less apparent• Both interact withcomponents of thelandscape3© 2011 Pearson Education, Inc.Figure 10-1b
  4. 4. The Geographic Approach to theStudy of Organisms• Simplest organisms still extraordinarily complex• Seek patterns of distribution of living organisms—biogeography• Several biological classification schemes– Most common, binomial, “two name”• 600,000 species of plants; twice that of animals• Biota—total complex of plant and animal life– Flora: plant life– Fauna: animal life• Ocean biota—plankton, nekton, and benthos4© 2011 Pearson Education, Inc.
  5. 5. Biogeochemical Cycles• Organisms survive throughcomplex of systemic flowsof energy, water, andnutrients• Cycles through whichEarth’s chemical elementsare absorbed byorganisms and returned toEarth throughdecomposition—biogeochemical cycles5© 2011 Pearson Education, Inc.Figure 10-2
  6. 6. Biogeochemical Cycles• The flow of energy– Sun is source on which alllife depends– Photosynthesis andrespiration– Food chain– Energy must be convertedto a usable form andrecycled6© 2011 Pearson Education, Inc.Figure 10-3
  7. 7. Biogeochemical Cycles• Photosynthesis– Biosphere receives solar energy– Chlorophyll– Chemical equation• CO2 + H2O = Carbohydrates + O2– Energy distributed by animals eating plants or eachother– Energy distributed in the plants through respiration– Plant respiration equation• Carbohydrates + O2 = CO2 + H2O + Energy (heat)7© 2011 Pearson Education, Inc.
  8. 8. Biogeochemical Cycles• Net primary production– Net photosynthesis—difference incarbohydrates producedto those lost to respiration– Net primary production isthe net photosynthesisover a year (Figure 10-4)– Measure of chemicalenergy in a plant– Reflected in the dryweight, or biomass, of thematerial8© 2011 Pearson Education, Inc.Figure 10-4
  9. 9. Biogeochemical Cycles• The Hydrologic Cycle– Every living thingdepends on water supply– Water dissolves nutrientsand carries them to allparts of the organism– Two ways water is foundin biosphere• In residence: chemicallybound to plant and animaltissue• In transit: part oftranspiration-respiration9© 2011 Pearson Education, Inc.
  10. 10. Biogeochemical Cycles• The Carbon Cycle– Biosphere containscomplex mixture of carboncompounds– Main components• Transfer of carbon from CO2 toliving matter and back to CO2– Rapid process (years notcenturies)– Gradual incorporation ofstored carbon in rock– Fossil fuels increase CO210© 2011 Pearson Education, Inc.Figure 10-6
  11. 11. Biogeochemical Cycles• The Oxygen Cycle– Building block in mostorganic molecules– By-product of plant life– Occurs in many formsand is released in manyways– Sources include water,carbon dioxide, ozone,oxygen stored in rocks11© 2011 Pearson Education, Inc.Figure 10-7
  12. 12. Biogeochemical Cycles• The Nitrogen Cycle– Nitrogen only usable in gasform by a few bacteria– Nitrogen usable by otherorganisms as nitrates thatare used in plants—nitrogenfixation– Waste converts nitrates towaste nitrites– Bacteria convert nitritesback to nitrates and nitrogengas (denitrification)12© 2011 Pearson Education, Inc.Figure 10-8
  13. 13. Biogeochemical Cycles• Other mineral cycles—other minerals critical to thebiosphere– Phosphorous– Sulfur– Calcium• Gaseous pathways—interchange between biota andatmosphere-ocean environment• Sedimentary pathways—element is weathered andreaches the groundwater; returned to the ocean and isconsumed by ocean organisms13© 2011 Pearson Education, Inc.
  14. 14. Food Chains• Food chain—directpassage from oneorganism to another ofnutrients• More complex—food“web”• Primary energytransformationmechanism14© 2011 Pearson Education, Inc.Figure 10-9
  15. 15. Food Chains• Fundamental unit: producers(autotrophs), self feeders• Producers eaten byconsumers (heterotrophs)– Primary consumers:herbivores– Secondary consumers:carnivores• Food pyramid• Decomposers begin the foodpyramid again15© 2011 Pearson Education, Inc.Figure 10-10
  16. 16. Food Chains• Energy is inefficientlyconsumed between differentfood pyramid levels• Pollutants in the food chain– Biological amplification– Chemical pesticides andheavy metals (mercury, lead)– Irrigation-related issues16© 2011 Pearson Education, Inc.Figure 10-11
  17. 17. Natural Distributions• Four basic conditions• Evolutionary development– Survival of the fittest– Where did the genus(closely related organismgroup) evolve?• Some localized• Several scattered localities ofthe same genus17© 2011 Pearson Education, Inc.Figure 10-12
  18. 18. Natural Distributions• Migration and dispersal– Animals move from oneplace to another– Plants move through seeddispersal– Distribution pattern oforganisms results fromnatural migration ordispersal from the originaldevelopment center18© 2011 Pearson Education, Inc.Figure 10-14
  19. 19. Natural Distributions• Reproductive success– Ability for organisms toreproduce affectsdistribution– Factors resulting in poorreproductive success• Heavy predation• Climate change• Food supply failure• Changing environmentalconditions19© 2011 Pearson Education, Inc.Figure 10-16
  20. 20. Natural Distributions• Extinction and die-off– Range diminution• Small areal changes• Mass extinction– Plant succession—onevegetation type replaced byanother (Figure 10-17)• Occur after catastrophic events• Primary succession—pioneercommunity• Secondary succession– Extinction versus succession20© 2011 Pearson Education, Inc.Figure 10-17
  21. 21. Environmental Relationships• Relationships of plants and animals depends onenvironment• Influences depend on the area of interest– Large area: seasonal characteristics, location– Small area: localized terrain, topsoil• Interspecific versus intraspecific competition• Limiting factor: most important variable for thesurvival of an organism21© 2011 Pearson Education, Inc.
  22. 22. Environmental Relationships• The influence of climate– Light• green plants need light to survive• Light changes shapes of plants(Figure 10-19)• Photoperiodism: stimulatesseasonal plant behavior– Moisture• Distribution of biota governedmore by moisture than any otherfactor• Biota evolution dictated byadaptation to moisture conditions22© 2011 Pearson Education, Inc.Figure 10-19Figure 10-20
  23. 23. Environmental Relationships• The influence of climate– Temperature• Different species can survive indifferent temperatures• Plants have limited coldtemperature tolerance– Wind• Wind effects generally limited• Persistent winds can havelimiting effects through increaseddrying• Strong winds can be destructiveto biota23© 2011 Pearson Education, Inc.Figure 10-21
  24. 24. Environmental Relationships• Topographic influences– Plants and animals in a plainsregion vastly different from amountainous region– Slope and drainage• Wildfires– Result in complete or partialdevastation of plant live anddeath or driving away of animals– Can be helpful for regrowth andmaintaining of plant type24© 2011 Pearson Education, Inc.Figure 10-22
  25. 25. Environmental Relationships• Example of selva (rainforest)– Occurs when climate is warm andhas abundant precipitation– Abundance of precipitation andwarmth leads to abundance ofnatural vegetation (flora), jungle– Numerous plants allow for fauna– Leaves, trees, branchesdecomposed by abundant faunaon floor, put into soil– Water runoff25© 2011 Pearson Education, Inc.Figure 10-24
  26. 26. Summary• Plants and animals impact and interact with thelandscape in numerous ways• Need a classification scheme for biota to understandgeographically• Flora and fauna refer to plants and animals,respectively• Energy originates from the Sun and flows to organismsthrough photosynthesis• The hydrologic cycle describes the transition of waterthrough the biosphere• The interaction of carbon with the biosphere is thecarbon cycle 26© 2011 Pearson Education, Inc.
  27. 27. Summary• Oxygen and nitrogen cycle through the biospherethrough the oxygen and nitrogen cycles, respectively• Other minerals cycle through the biosphere as well, butthey are not as commonly observed• Food chains describe the passage of energy from oneorganism to another• There are four primary components to the naturaldistributions of biota• Numerous environmental relationships affect whichbiota exist in which regions27© 2011 Pearson Education, Inc.