Chapter 5 Populations

1
Chapter 5Populations

• Section 5-2
• Limits To Growth

2
Limiting Factors

• Cause Population Growth to DECREASE!
• Competition
• Predation
• Parasitism Disease
• Climate Extremes
• Human Disturbances

3
Density-Dependent Factors

• Are Limiting Factors that depend on increased
  population size (density) for activation.
• competition predation
• parasitism disease

4
Competition

• Battles between members of own species for
  limited resources.

5
Competition

• Between different species is a major force behind
  evolutionary change
• Results in the formation of NICHES

6
Competition
7
Predation

• Predator/Prey Relationship
• Balances, Stabilizes Populations
• Wolves Moose
• 50 kg Wolf needs 2700 kg Moose per year
• Average Moose is 385 kg
• How many Moose need to be eaten each year?

8
Predation

• 2700/385 7.01 Moose per Year
• A pack of 8 wolves will kill how many Moose per
  year?

9
Parasitism Disease

• Weaken Host
• Makes Host Susceptible To Predation
• May Kill Host.

10
Density-Independent Factors

• Affect population regardless of size.
• Unusual Weather
• Natural Disasters
• Seasonal Cycles
• Human Activities
• Dams
• Clear Cutting

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Density-Independent Factors

• Result in crash in population size
• May result in extinction