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Ch 7 8 ppt 2010 student notes

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Ch 7 - 8 student template notes

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Ch 7 8 ppt 2010 student notes

  1. 1. Chapter 7 - Biological Diversity and Biogeography Case Study Purple Loosestrife
  2. 2. What is biological evolution? <ul><li>It’s the change in inherited characteristics of a population from generation to generation. </li></ul><ul><li>What are some process that lead to biological evolution? </li></ul><ul><li>1. </li></ul><ul><li>2. </li></ul><ul><li>3. </li></ul><ul><li>4. </li></ul><ul><li>5. </li></ul>
  3. 3. <ul><li>Mutations may: </li></ul>
  4. 4. <ul><li>Natural Selection </li></ul><ul><li>Relies on variation of individuals within a species. Genetic diversity is key! </li></ul><ul><li>Those orgs with traits that make them better fit or adapted survive well, reproduce more and pass these helpful traits on to their offspring. </li></ul><ul><li>Peppered moth = classic example. </li></ul>
  5. 5. Photos by Ken Miller
  6. 6. <ul><li>Speciation (evolution of a new species) </li></ul><ul><li>1. Geographic isolation of two populations of the same species </li></ul><ul><li>2. They each evolve separately </li></ul><ul><li>3. Eventually differences accumulate </li></ul>
  7. 8. Reproductive isolation can occur due to mutations too.
  8. 9. <ul><li>Migration </li></ul><ul><li>During migration different selective pressures may be encountered. </li></ul><ul><li>Populations may become separated </li></ul><ul><li>Genetic Drift </li></ul><ul><li>Changes in gene frequency of a population due to chance - not due to being better adapted </li></ul><ul><li>May greatly impact small populations </li></ul><ul><li>Dangerous for rare and endangered species </li></ul>
  9. 10. Extreme hunting left only 20 Few individuals left – why?
  10. 11. Basic Concepts of Biodiversity <ul><li>3 major concepts: </li></ul><ul><li>1. Genetic diversity </li></ul><ul><li>2. Habitat diversity: </li></ul>
  11. 12. <ul><li>3. Species diversity: </li></ul><ul><li>a. Species richness – </li></ul><ul><li>b. Species evenness – </li></ul><ul><li>c. Species dominance - </li></ul>
  12. 13. Hwk <ul><li>Shannon-Weiner Biodiversity Index </li></ul><ul><li>Read and do sample problems. </li></ul><ul><li>Show all work and solve for H ’ </li></ul><ul><li>Also: Calculate Evenness for each problem: </li></ul><ul><ul><li>Evenness: </li></ul></ul><ul><ul><li>Formula = H’ / ln S </li></ul></ul><ul><ul><li>S = number of different species </li></ul></ul><ul><ul><li>(Absolute evenness = 1) </li></ul></ul>
  13. 14. Hwk <ul><li>Pre-lab work for Wed. </li></ul><ul><li>Answer pre-lab questions. </li></ul><ul><li>#1 in INB. </li></ul><ul><li>#2 and 3 become your hypothesis, under purpose on title pg. </li></ul><ul><li>Calculate S-W biodiversity index for both pictures (fig. 7.4) on page 123. </li></ul><ul><li>Solve for H ’ and Evenness. </li></ul><ul><li>Show all work. </li></ul>
  14. 15. <ul><li>Species habitat terms: </li></ul><ul><li> exotic = introduced </li></ul><ul><li>endemic = native </li></ul><ul><li>cosmopolitan - very broad distribution but need similar habitat </li></ul><ul><li> ubiquitous = found almost everywhere even very different habitats </li></ul>
  15. 16. How many species on Earth? <ul><li>Uncertain </li></ul><ul><li>Prior to fogging study: Range = </li></ul><ul><li>1 - 3 million </li></ul><ul><li>After study: 10 -100 million! </li></ul>
  16. 17. Interactions Between Species <ul><li>3 kinds: </li></ul><ul><li>1. Competition: negative for both </li></ul>
  17. 18. <ul><li>2. Symbiosis: both benefit </li></ul><ul><li>It is very common; exists amongst most plants and animals </li></ul>
  18. 19. <ul><li>3. Predation - parasitism: positive for one and negative for the other </li></ul>
  19. 20. <ul><li>Exclusion Dominance and Diversity: The Competitive Principle </li></ul><ul><li>Competitive exclusion = 2 species with exact same requirements cannot coexist in the same habitat. They will compete and the more fit one will win out and persist </li></ul>
  20. 21. © 2003 John Wiley and Sons Publishers Fig 7.6 A classical experiment with flour beetles.
  21. 22. <ul><li>Niche: how species co-exist. </li></ul><ul><li>A habitat is where an org lives as compared to what it does to survive, which is its’ ecological niche </li></ul><ul><li>Species that require the same resources can coexist only if they can utilize them under different env. conditions (different ecological niches). </li></ul>
  22. 23. <ul><li>Species that require the same resources can coexist only if they can utilize them under different env. conditions (different ecological niches). </li></ul>
  23. 24. <ul><li>Niches can be measured: </li></ul><ul><li>The range of niche a species will occupy with no competitor is called its’ fundamental niche </li></ul><ul><li>The range in which it actually lives, if it is having to compete, is called its’ realized niche </li></ul>
  24. 25. © 2003 John Wiley and Sons Publishers Fig 7.7 The occurrence of freshwater flatworms in cold mountain streams in Great Britain.
  25. 26. Environmental Factors That Influence Diversity!! <ul><li>Diversity varies from place to place </li></ul><ul><li>Generally, greater in lower latitudes </li></ul>
  26. 27. <ul><li>Ecological gradient: the change in relative abundance of a species over an area (ie: change in elevation in the mtns.) </li></ul>
  27. 28. © 2003 John Wiley and Sons Publishers Fig 7.10 Change in the relative abundance of a species over an area or a distance is referred to as an ecological gradient.
  28. 29. <ul><li>Factors that increase or decrease diversity: </li></ul><ul><li>Increase diversity : </li></ul><ul><li>1. Physically diverse habitat </li></ul><ul><li>2. Moderate disturbance </li></ul><ul><li>3. Small variation in env. conditions </li></ul><ul><li>4. High diversity at one trophic level increases diversity of another level </li></ul>
  29. 30. <ul><li>Decrease diversity </li></ul><ul><li>1. Environmental stress </li></ul><ul><li>2. Extreme environmental conditions </li></ul><ul><li>3. Severe limitation of an essential resource </li></ul><ul><li>4. Extreme disturbance </li></ul><ul><li>5. Recent exotic species </li></ul><ul><li>6. Geographic isolation (island effect) </li></ul>
  30. 31. <ul><li>Humans greatly affect diversity : </li></ul><ul><ul><li>Development and industry </li></ul></ul><ul><ul><li>Favoring one species over another </li></ul></ul><ul><ul><li>Manipulating environments </li></ul></ul><ul><li>Species diversity in an area may change over time, seasons, decades, centuries... </li></ul>
  31. 32. The Geography of Life <ul><li>The kinds and numbers of species varies greatly from place to place. These large-scale global patterns are called biogeography </li></ul>
  32. 33. <ul><li>Biotic Provinces </li></ul><ul><li>Six “realms” were identified in 1876 based on the types of animals found there: </li></ul><ul><li>(Remember: classification of orgs are based on evolutionary relationships or similar characteristics) </li></ul>
  33. 34. © 2003 John Wiley and Sons Publishers Fig 8.3 The major vegetation realms are also based on genetic factors.
  34. 35. <ul><li>Continental drift explains the origin of these provinces as land masses periodically unified (genetic mix and spread of species) and then separated (isolation and speciation) </li></ul>
  35. 36. <ul><li>Biomes : </li></ul><ul><li>Each continent has diverse climates and habitats so diversity of species is high </li></ul><ul><li>Biome = a kind of ecosystem </li></ul><ul><li>Similar environmental conditions (selective pressures) lead to evolution of orgs similar in form and function but not genetic heritage or internal make-up. </li></ul>
  36. 37. © 2003 John Wiley and Sons Publishers Fig 8.13 Global distribution of the major land biomes.
  37. 38. <ul><li>Divergent evolution occurs when a pop. is separated and evolves in isolation from main groups, often under different selective pressures. They have common ancestry and retain some common characteristics of their ancestors. (ex: marine mammals) </li></ul>
  38. 40. © 2003 John Wiley and Sons Publishers Fig 8.10 Evolutionary divergence among honeycreepers in Hawaii.
  39. 41. <ul><li>Island Biogeography </li></ul><ul><ul><li>Generally observe adaptive radiation: species evolve by divergent evolution as they separate into smaller groups, often on different islands, each adapting to a more specialized role (niche) </li></ul></ul><ul><ul><li>Species diversity and islands: </li></ul></ul>
  40. 42. © 2003 John Wiley and Sons Publishers Fig 8.11 Idealized relation of an island’s size, distance from the mainland, and number of species. Pg 138

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