Section 14-3 and 14-4

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Section 14-3 and 14-4Population

• Write everything that is underlined

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Section 14.3 KEY CONCEPT Each population has a
density, a dispersion, and a reproductive
strategy.
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• Populations
• Population density is a measurement of the number
  of individuals living in a defined space.
• Population dispersion refers to how a population
  is spread in an area.
• There are three types of dispersion illustrated
  on the next slides

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a. clumped
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b.uniform
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c. random
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• Survivorship curves

• Type I low level of infant mortality and an
  older population
• common to large mammals and humans
• Type II survivorship rate is equal at all stages
  of life
• common to birdsand reptiles

• Type III very high birth rate, very high infant
  mortality
• common to invertebrates and plants

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Section 14.4 KEY CONCEPT Populations grow in
predictable patterns.
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• Population Growth
• The size of a population is always changing.
• Four factors affect the size of a population
• Births
• Deaths
• Immigration
• (Moving into an area)
• Emigration
• (Moving out of an area)

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1. Exponential growth is a rapid population increase
   due to an abundance (lots of) of resources.

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1. Logistic growth is due to a population facing
   limited resources.

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• Carrying capacity is the maximum number of
  individuals in a population that the environment
  can support.
• This is due to limited resources (food, shelter,
  space)

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• A population crash is a dramatic decline in the
  size of a population over a short period of time.

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1. A limiting factor is something that keeps the
   size of a population down.

• Limiting factors can depend on the density of
  individuals in the population or not.

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1. Density-dependent limiting factors are affected
   by the number of individuals in a given area.

• Predation
• Competition
• Parasitism and disease

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1. Density-independent limiting factors limit a
   populations growth regardless of the density.

1. unusual weather
2. natural disasters
3. human activities