5.1: Communities Topic 5: Ecology & Evolution Miss Friedman
5.1.1: Definitions <ul><li>Ecology </li></ul><ul><li>The study of the relationship between living organisms and between th...
5.1.1: Definitions <ul><li>Community </li></ul><ul><li>Populations of different species in the same area which are interac...
5.1.2: Autotrophs & heterotrophs Obtains organic molecules from other organisms consumer Heterotroph An organism that synt...
5.1.3: Consumers, detritivores, saprophytes <ul><li>Consumers </li></ul><ul><li>An organism that ingests other organic mat...
5.1.4: Food chains <ul><li>Food chains show a simple linear flow of “who eats who”  </li></ul><ul><li>Therefore shows the ...
 
5.1.5: Food webs <ul><li>A diagram that shows how food chains are linked together into more complex feeding relationships ...
 
5.1.6: Trophic level <ul><li>The tropic level of an organism defines the feeding relationship of that organism to other or...
5.1.7: Determining tropic levels in food chains/webs <ul><li>Assign tropic levels to the food web on the right! </li></ul>
5.1.8: Constructing a food web <ul><li>Producers are usually shown at the bottom </li></ul><ul><li>Use full name of organi...
5.1.9:Light & food chains <ul><li>Sunlight is the source of energy for most communities, both aquatic and terrestrial </li...
5.1.10: Energy flow in Food chain <ul><li>a)  Not all solar energy will come into contact with chlorophyll and will theref...
5.1.11: Efficiency of energy transformations <ul><li>When energy is changed from one form into another, it is never 100% e...
5.1.12: Shape of energy pyramids <ul><li>A  pyramid of energy  is a graphical representation of the amount of energy of ea...
5.1.13: Energy and matter in ecosystems <ul><li>Energy is NOT recycled through the ecosystem </li></ul><ul><li>Energy is c...
5.1.14: Decomposers <ul><li>Two main groups are  detritivores  (e.g. earthworms, dung beetles) and  saprotrophs  (e.g. fun...
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5.1 Communities

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IB Topic 5: Ecology

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5.1 Communities

  1. 1. 5.1: Communities Topic 5: Ecology & Evolution Miss Friedman
  2. 2. 5.1.1: Definitions <ul><li>Ecology </li></ul><ul><li>The study of the relationship between living organisms and between those organisms and their environment </li></ul><ul><li>Ecosystem </li></ul><ul><li>A community and its abiotic environment </li></ul><ul><li>Population </li></ul><ul><li>A group of organisms of the same species who live in the same area at the same time </li></ul>
  3. 3. 5.1.1: Definitions <ul><li>Community </li></ul><ul><li>Populations of different species in the same area which are interacting </li></ul><ul><li>Species </li></ul><ul><li>A group of organisms which can interbreed and produce fertile offspring </li></ul><ul><li>Habitat </li></ul><ul><li>Location within which a species normally lives </li></ul>
  4. 4. 5.1.2: Autotrophs & heterotrophs Obtains organic molecules from other organisms consumer Heterotroph An organism that synthesises its organic molecules from simple inorganic molecules Producer Autotroph
  5. 5. 5.1.3: Consumers, detritivores, saprophytes <ul><li>Consumers </li></ul><ul><li>An organism that ingests other organic matter that is living or recently dead </li></ul><ul><li>Detritivores </li></ul><ul><li>An organism that ingests non-living organic matter </li></ul><ul><li>Saprophytes </li></ul><ul><li>An organism that lives on or in non-living organic matter, secreting digestive enzymes into and absorbing the products of digestion </li></ul>
  6. 6. 5.1.4: Food chains <ul><li>Food chains show a simple linear flow of “who eats who” </li></ul><ul><li>Therefore shows the energy flowing through the links in the chain </li></ul><ul><li>Questions to consider! </li></ul><ul><li>How is energy lost in the chain? </li></ul><ul><li>Why are big, dangerous predators so rare? </li></ul>
  7. 8. 5.1.5: Food webs <ul><li>A diagram that shows how food chains are linked together into more complex feeding relationships </li></ul><ul><li>Advantages over food chain </li></ul><ul><li>Shows much more complex interactions between species within a community/ecosystem </li></ul><ul><li>More than one producer supports a community </li></ul><ul><li>A single producer is a food source for many primary consumers </li></ul><ul><li>A consumer might have a number of different food sources on the same/different trophic levels </li></ul><ul><li>A consumer can be an omnivore, feeding as a primary consumer but also as a consumer at higher tropic levels </li></ul>
  8. 10. 5.1.6: Trophic level <ul><li>The tropic level of an organism defines the feeding relationship of that organism to other organisms in a food web </li></ul>Trophic level 4 Tertiary consumer heterotroph Trophic level 3 Secondary consumer Hetertroph Tropic level 2 Primary consumer Hetertroph Tropic level 1 Producer Autotraph
  9. 11. 5.1.7: Determining tropic levels in food chains/webs <ul><li>Assign tropic levels to the food web on the right! </li></ul>
  10. 12. 5.1.8: Constructing a food web <ul><li>Producers are usually shown at the bottom </li></ul><ul><li>Use full name of organisms </li></ul><ul><li>Arrows show the movement of matter & energy </li></ul>
  11. 13. 5.1.9:Light & food chains <ul><li>Sunlight is the source of energy for most communities, both aquatic and terrestrial </li></ul><ul><li>Very few communities deep in the ocean use geothermal energy </li></ul>
  12. 14. 5.1.10: Energy flow in Food chain <ul><li>a) Not all solar energy will come into contact with chlorophyll and will therefore not be trapped in the synthesis of organic compounds </li></ul><ul><li>b) Photosynthesis </li></ul><ul><li>c) Consumers feeding and passing on energy in the food </li></ul><ul><li>d) Loss of energy as heat from respiration </li></ul><ul><li>e) death and the consumption of dead organisms by detritivores. Or as food not assimilated because of incomplete digestion. </li></ul><ul><li>Energy Loss </li></ul><ul><li>loss of energy in undigested food which will then be used by saprophytes/ decomposers </li></ul><ul><li>loss of heat energy in the reactions of respiration </li></ul><ul><li>ultimately all energy will be lost has heat </li></ul>
  13. 15. 5.1.11: Efficiency of energy transformations <ul><li>When energy is changed from one form into another, it is never 100% efficient </li></ul><ul><li>Approximately only 10-20% of the energy on one trophic level will be assimilated at the next higher trophic level </li></ul>
  14. 16. 5.1.12: Shape of energy pyramids <ul><li>A pyramid of energy is a graphical representation of the amount of energy of each trophic level in a food chain </li></ul><ul><li>The units are kJ/m 2 /yr </li></ul><ul><li>The narrowing shape illustrates the gradual loss of energy processing along the links of a food chain to higher trophic levels </li></ul>
  15. 17. 5.1.13: Energy and matter in ecosystems <ul><li>Energy is NOT recycled through the ecosystem </li></ul><ul><li>Energy is constantly received from the sun and constantly radiates out in the form of light & heat </li></ul><ul><li>Matter IS recycled </li></ul><ul><li>The process of recycling nutrients requires energy </li></ul>
  16. 18. 5.1.14: Decomposers <ul><li>Two main groups are detritivores (e.g. earthworms, dung beetles) and saprotrophs (e.g. fungi, bacteria) </li></ul><ul><li>Decomposition is a complex process and serves many functions; formation of soil, recycling of nutrients, reduction of high energy carbon compounds </li></ul><ul><li>Organic molecules are oxidized to release nitrogen in the form of nitrate, nitrite, and ammonia </li></ul><ul><li>Oxidation of organic compounds provides energy for saprophyte but returns matter to abiotic environment </li></ul>

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