Biology - Chp 3 - The Biosphere - PowerPoint


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Biology - Chp 3 - The Biosphere - PowerPoint

  1. 1. Chapter 3 The Biosphere
  2. 2. 3-1 What is Ecology
  3. 3. Objectives• Identify the levels of organization that ecologists study• Describe the methods used to study ecology
  4. 4. Ecology• The scientific study of interactions among organisms and between their environment
  5. 5. Biosphere• The portion of the planet which all life exists
  6. 6. Levels of Organization• To understand relationships within the biosphere ecologists ask questions about events and organisms that range in complexity from single individuals to the entire biosphere• Studies can focus on…
  7. 7. Species• A group of organisms similar to one another that can breed together
  8. 8. Populations• Groups of individuals that belong to the same species and live in the same area
  9. 9. Communities• Assemblages of different populations that live in a particular place together with their non-living physical environment
  10. 10. Ecosystem• Collection of all the organisms that live in a particular place, together with their non-living environment
  11. 11. Biome• A group of ecosystems that have the same climate and similar dominant communities
  12. 12. Ecological Methods1. Observing2. Experimentation3. Modeling
  13. 13. 3 – 2 Energy Flow
  14. 14. Objectives• Identify the source of energy for life processes• Trace the flow of energy through living systems• Evaluate the efficiency of energy transfer among organisms in an ecosystem
  15. 15. Producers• Sunlight is the main energy source for life on Earth• Some types of organisms rely on the energy stored in organic chemical compounds
  16. 16. Producers (autotrophs)• Use energy from the environment to make their own foodEx.) plants, some algae, certain types of bacteria
  17. 17. Photosynthesis• Process that converts light energy, carbon dioxide and water into oxygen, sugars and starches
  18. 18. Chemosynthesis• The process that converts chemical energy into carbohydrates
  19. 19. Consumers (heterotrophs) • Organisms that rely on other organisms for their energy and food supply
  20. 20. Herbivores• Eat plants
  21. 21. Carnivores• Eat animals
  22. 22. Detritivores• Feed on plant and animal remains and other dead matterEx.) mites, earthworms, snails, crabs
  23. 23. Decomposers• Break down organic matter• Ex.) fungi, bacteria
  24. 24. Feeding Relationships• Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers)
  25. 25. Food Chain• A series of steps in which organisms transfer energy by eating or being eaten
  26. 26. Food Web• A network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem
  27. 27. Trophic Levels• Each step in a food chain or food web1st – Producers2nd – 3rd or higher – consumers• Each consumer depends on the trophic level below it for energy
  28. 28. Ecological Pyramid• A diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or food web
  29. 29. Energy Pyramid• A diagram that shows the relative amounts of energy available of each level
  30. 30. • Only about 10% of energy available within one trophic level is transferred to organisms at the next trophic level
  31. 31. Biomass Pyramid• Represent the amount of food available for each trophic level
  32. 32. biomass• The total amount of living tissue within a given trophic level
  33. 33. Pyramid of numbers• Shows the relative number of individual organisms at each trophic level
  34. 34. 3 – 3 Cycles of Matter
  35. 35. Objectives• Describe how matter cycles among the living and nonliving parts of an ecosystem• Explain why nutrients are important in living systems• Describe how the availability of nutrients affects the productivity of ecosystems
  36. 36. • Energy is crucial to an ecosystem, but organisms need more than that to survive• They also need• Water• Minerals/nutrients• Oxygen• Carbon• Nitrogen• Phosphorus
  37. 37. Recycling in the Biosphere• Unlike the one way flow of energy, matter is recycled within and between ecosystems
  38. 38. Evaporation• The process by which water changes from liquid form to an atmospheric gas
  39. 39. Transpiration• The process by which water can enter the atmosphere by evaporating from leaves of plants
  40. 40. Condensation• Forming Clouds
  41. 41. Precipitation• When water returns to the earths surface
  42. 42. Nutrients• All the chemical substances that an organism needs to live• Every living organism needs nutrients to grow and carry out essential life functions. Like water; nutrients are passed between organisms and the environment through cycles
  43. 43. The Carbon cycle• There are 4 different kinds of processes involved in the carbon cycle:1. Biological processes2. Geochemical processes3. Mixed biogeochemical processes4. Human activity
  44. 44. The Nitrogen Cycle• All organisms require nitrogen to make amino acids, which in turn are used to build proteins• Many different forms of nitrogen occur naturally in the biosphere• Although nitrogen gas is the most abundant form of nitrogen on Earth, only certain types of bacteria can use this form directly
  45. 45. Nitrogen fixation• Process of converting nitrogen gas into useful forms
  46. 46. The Phosphorus Cycle• Phosphorus is essential to living organisms because it forms part of important life sustaining molecules such as DNA and RNA• Unlike carbon, oxygen and nitrogen, phosphorus does not enter the atmosphere• Phosphorus remains mostly on land in rock and soil minerals, and in ocean sediments• As the rocks and sediments gradually wear down, phosphate is released• Plants absorb phosphate then it moves to the rest of the ecosystem
  47. 47. Nutrient Limitation• Ecologists are often interested in the primary productivity of an ecosystem
  48. 48. Primary Productivity• The rate at which organic matter is created by producers• If a nutrient is in short supply, it will limit an organisms growth
  49. 49. Limiting Nutrient• Single nutrient that either is scarce or cycles very slowly, limiting the growth of organisms in an ecosystem