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MULTIDISCIPLINRY NATURE OF THE ENVIRONMENTAL STUDIES.pptx
Regulating populations
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
4. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
Resource limit reached
Population
Resources Plentiful
Time
5. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
Equilibrium Point
Resource limit reached
Population
Resources Plentiful
Time
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
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. 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. 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. 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
13. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
• Density independent factors also
regulate population size for many
organisms
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. 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. 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. 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
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. 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. 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. 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
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. 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. 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
28. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
• Equilibrium or Boom and bust
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. 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. 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
33. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
• Equilibrium or Boom and bust
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. 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. 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
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. 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. 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. 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
45. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
K strategists
• Low reproductive rate
46. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
K strategists
• Low reproductive rate
• Large investment in parental
care
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. 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. 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. 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. 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. 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. 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
56. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
r strategists
• High reproductive rate
57. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
r strategists
• High reproductive rate
• Low investment in parental care
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. 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. 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. 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. 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. 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. Topic 2: Ecosystems
2.6 Changes
2.6.3 What regulates populations
The reality is more of a continuum
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
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. 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. 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. 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