8.2 Changes in population size Flashcards

1
Q

what does the growth curve of
populations consists of

A
  • Lag phase
  • Log/exponential phase
  • Stationary phase
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2
Q

Lag phase:

A

the period in population growth when an organism is adapting to its new environment and the growth is slow.

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3
Q

Log/exponential phase

A

when the growth rate of a population increases over time as all requirements are in superabundance.

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4
Q

Stationary phase

A

no growth – population remains stable It is at the carrying capacity

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5
Q

Carrying capacity:

A

the maximum size of a population that an environment can support in terms of food, water and other resources.

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6
Q

birth rate

A

the number of live births per thousand of the population per year.

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7
Q

death rate

A

the number of deaths per thousand of the population per year.

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8
Q

calculation for natural increase

A

BR-DR/10

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9
Q

calculation for natural decrease

A

DR-BR/10

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10
Q

REASONS FOR HIGH BIRTH RATE

A
  • Pro-natalist policies (governments encouraging couples to have more children)
  • High infant mortality (if some babies may die, couples will be tempted to have more children)
  • Lack of contraception
  • In farming economies of many LEDCs, more people are needed for manual labour; hence families tend to be larger
  • No care homes or pensions so old dependents will need their children to care for them in old age.
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11
Q

REASONS FOR LOW BIRTH RATE

A
  • Availability and affordability of contraception
  • Reduced infant mortality
  • Anti-natalist policies e.g. China’s one child policy
  • High cost of raising children
  • As pensions are provided, they do not need children to take care of them in their old age.
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12
Q

REASONS FOR HIGH DEATH RATE

7

A
  • Natural disasters
  • Poor medical care
  • Poor hygiene and sanitation
  • Poor diet
  • Lack of exercise
  • Shortage of clean water
  • Diseases
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13
Q

REASONS FOR LOW DEATH RATE

A
  • Good housing conditions
  • Safe water supplies
  • More than enough food to eat
  • Advanced medical services which are easy to access
  • Improved levels of exercise
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14
Q

migration

A

the movement of people into (immigration) or out of (emigration) a region, country or area

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15
Q

Population growth calculation:

A
  • birth rate – death rate
  • (birth rate + immigration) – (death rate + emigration)
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16
Q

Push factors (rural to urban)
(8)

A
  • drought
  • sea level rise
  • desertification
  • seasonal weather events
  • poor services
  • low salary
  • poor housing
  • poverty
17
Q

pull factors (rural to urban)

A
  • well-paid jobs
  • good services e.g hospitals, schools
  • good supplies of food
  • peaceful and safe
18
Q

push factors (urban to rural)

A
  • cost of housing
  • language barries
  • racial tension
  • different culture
  • no friends and family