What%20is%20Ecology?

1
Populations and Ecosystems
"Population, when unchecked, increases in a
geometrical ratio. Subsistence only increases in
an arithmetical ratio." Thomas Malthus, "An
Essay on the Principle of Population 1798
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Population Size

• growth
• limiting factors
• carrying capacity

3
Contributions to Growth

• Increase in Size due to
• Birth
• Immigration
• Decrease in Size due to
• Death
• Emigration

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Unlimited Growth

P(t) P0 ert
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Real Growth Curves
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Limiting Factors Affecting Growth
Density Dependent Limiting Factors
Parasitism and disease
Predation
Competition
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Limited Growth Logistic Growth

E steady state
D slower growth
C slow growth
B exponential growth
A initial growth
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Carrying Capacity

E Steady State
Carrying Capacity
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Predation - a Density Dependent Factor
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Predation a textbook example
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Predation continued
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Predation predator-prey combined
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Predator Prey Game
Predator Prey Game
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Competition for space
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Disease
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17
How Many Worlds to you need?