Regulating populations

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Regulating populations

  1. 1. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Density dependent factors tend to act as direct regulators of populations • Negative Feedback
  2. 2. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations Population Time
  3. 3. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations Population Time
  4. 4. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations Resource limit reached Population Resources Plentiful Time
  5. 5. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations Equilibrium Point Resource limit reached Population Resources Plentiful Time
  6. 6. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations Equilibrium Point Steady State Equilibrium Resource limit reached Population Resources Plentiful Time
  7. 7. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations Falco pereginus
  8. 8. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Until the 1940’s the British population of Peregrine falcons had remained fairly constant - about 820 breeding pairs Falco pereginus
  9. 9. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Until the 1940’s the British population of Peregrine falcons had remained fairly constant - about 820 breeding pairs • Limited by available nest sites (same places each year) Falco pereginus
  10. 10. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Until the 1940’s the British population of Peregrine falcons had remained fairly constant - about 820 breeding pairs • Limited by available nest sites (same places each year) • Average brood size was about 2.5 fledged young each summer Falco pereginus
  11. 11. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Until the 1940’s the British population of Peregrine falcons had remained fairly constant - about 820 breeding pairs • Limited by available nest sites (same places each year) • Average brood size was about 2.5 fledged young each summer • Come the next breeding season the population Falco pereginus was back to about 820 pairs
  12. 12. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  13. 13. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Density independent factors also regulate population size for many organisms
  14. 14. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Density independent factors also regulate population size for many organisms • Mosquitos are plentiful in the summer months
  15. 15. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Density independent factors also regulate population size for many organisms • Mosquitos are plentiful in the summer months • When autumn sets in the populations crash
  16. 16. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Density independent factors also regulate population size for many organisms • Mosquitos are plentiful in the summer months • When autumn sets in the populations crash • Boom or bust
  17. 17. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Density independent factors also regulate population size for many organisms • Mosquitos are plentiful in the summer months Summer Population • When autumn sets in the populations crash Winter • Boom or bust Time
  18. 18. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  19. 19. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Boom or bust may also be driven by density dependent factors
  20. 20. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Boom or bust may also be driven by density dependent factors • Some species are very good at taking full advantage of any opportunity
  21. 21. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Boom or bust may also be driven by density dependent factors • Some species are very good at taking full advantage of any opportunity • Locust populations can explode
  22. 22. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Boom or bust may also be driven by density dependent factors • Some species are very good at taking full advantage of any opportunity • Locust populations can explode • They swarm in thousands eat everything in their path and eventually totally outstrip their food supply
  23. 23. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  24. 24. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Factors that regulate population size can be categorized as INTERNAL or EXTERNAL
  25. 25. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Factors that regulate population size can be categorized as INTERNAL or EXTERNAL • INTERNAL - fertility rates, territory size
  26. 26. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Factors that regulate population size can be categorized as INTERNAL or EXTERNAL • INTERNAL - fertility rates, territory size • EXTERNAL - predation pressure, parasitism, disease
  27. 27. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  28. 28. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Equilibrium or Boom and bust
  29. 29. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Equilibrium or Boom and bust • Two types of life strategies can be identified
  30. 30. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Equilibrium or Boom and bust • Two types of life strategies can be identified • Equilibrium or K strategy species
  31. 31. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Equilibrium or Boom and bust • Two types of life strategies can be identified • Equilibrium or K strategy species • Opportunist or r strategy species
  32. 32. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  33. 33. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Equilibrium or Boom and bust
  34. 34. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Equilibrium or Boom and bust • Two types of life strategies can be identified
  35. 35. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Equilibrium or Boom and bust • Two types of life strategies can be identified • Equilibrium or K strategy species
  36. 36. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations • Equilibrium or Boom and bust • Two types of life strategies can be identified • Equilibrium or K strategy species • Opportunist or r strategy species
  37. 37. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  38. 38. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations What are K and r
  39. 39. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations What are K and r • The two variables that define a population curve
  40. 40. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations What are K and r • The two variables that define a population curve • K = carrying capacity
  41. 41. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations Population What are K and r 120 • The two variables that 100 define a population curve 80 • K = carrying capacity Growth 60 • r = growth rate 40 20 0 0 50 100 150 200 250 300 Time
  42. 42. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K Population What are K and r 120 • The two variables that 100 define a population curve 80 • K = carrying capacity Growth 60 • r = growth rate 40 20 0 0 100 200 300 400 500 600 Time
  43. 43. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  44. 44. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists
  45. 45. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Low reproductive rate
  46. 46. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Low reproductive rate • Large investment in parental care
  47. 47. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Low reproductive rate • Large investment in parental care • Late maturity
  48. 48. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Low reproductive rate • Large investment in parental care • Late maturity • Slow growth
  49. 49. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Low reproductive rate • Large investment in parental care • Late maturity • Slow growth • Large organisms
  50. 50. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Late successional species • Low reproductive rate • Large investment in parental care • Late maturity • Slow growth • Large organisms
  51. 51. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Late successional species • Low reproductive rate • Niche specialist • Large investment in parental care • Late maturity • Slow growth • Large organisms
  52. 52. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Late successional species • Low reproductive rate • Niche specialist • Large investment in parental • Require stable environment care • Late maturity • Slow growth • Large organisms
  53. 53. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations K strategists • Late successional species • Low reproductive rate • Niche specialist • Large investment in parental • Require stable environment care • Late maturity • Slow growth • Large organisms
  54. 54. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  55. 55. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists
  56. 56. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists • High reproductive rate
  57. 57. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists • High reproductive rate • Low investment in parental care
  58. 58. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists • High reproductive rate • Low investment in parental care • Early maturity
  59. 59. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists • High reproductive rate • Low investment in parental care • Early maturity • Rapid growth
  60. 60. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists • High reproductive rate • Low investment in parental care • Early maturity • Rapid growth • Small organisms
  61. 61. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists • Pioneer species species • High reproductive rate • Low investment in parental care • Early maturity • Rapid growth • Small organisms
  62. 62. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists • Pioneer species species • High reproductive rate • Generalists • Low investment in parental care • Early maturity • Rapid growth • Small organisms
  63. 63. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations r strategists • Pioneer species species • High reproductive rate • Generalists • Low investment in parental care • Rapidly adapt to environmental variation • Early maturity • Rapid growth • Small organisms
  64. 64. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations The reality is more of a continuum
  65. 65. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations The reality is more of a continuum Zebra Rabbit Bacteria r K
  66. 66. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  67. 67. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations
  68. 68. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations If life Tables (Survivorship) is plotted for different species three generalised types of life curve form
  69. 69. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations If life Tables (Survivorship) is plotted for different species three generalised types of life curve form Type 1 - Survivorship is high, most mortality later in life span
  70. 70. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations If life Tables (Survivorship) is plotted for different species three generalised types of life curve form Type 1 - Survivorship is high, most mortality later in life span Type II - Constant mortality throughout life span
  71. 71. Topic 2: Ecosystems 2.6 Changes 2.6.3 What regulates populations If life Tables (Survivorship) is plotted for different species three generalised types of life curve form Type 1 - Survivorship is high, most mortality later in life span Type II - Constant mortality throughout life span Type III - High mortality early in life, low survivorship into late life span

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