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POPULATION AND THE ENVIRONMENT
Population Growth
Population Ecology
- the study of the number of individuals of a particular species that are found in an area and how and why those numbers change over time
Population Growth cont’d
Population Density
- the number of individuals of a population per unit of habitat area
- e.g., the number of Grassquits per hectare
- e.g., the number of snapper per litre of sea water
Population Growth cont’d
Population Size
- the number of individuals making up a population
Population size changes due to:
• births
• deaths
• immigration
• emigration
Population Growth cont’d
Birth Rate (b)
- also called crude birth rate
- number of births per 1,000 individuals in a population in a given year
Death Rate (d)
- also called crude death rate
- number of deaths per 1,000 individuals in a population in a given year
Fertility Rate
- The number of children born to a woman
- Jamaica’s fertility rate is 2.41
Replacement Fertility Rate
- The fertility rate that is high enough to replace an area's population.
- In Industrialised countries it is 2.1
Population Growth cont’d
Immigration (i)
- movement of individuals into a population
Emigration (e)
- movement of individuals out of a population
Population Growth cont’d
Growth Rate (r)
- also called annual rate of natural population change
r = b – d
r = (b + i) – (d + e)
Biotic Potential
- maximum rate at which a population can increase when there are no limits on its growth
Population Growth cont’d
Exponential Growth
- growth in population size increases by a fixed percentage of the whole in a given time period
- yields a J-shaped curve
Exponential Growth cont’d
J-shaped Growth Curve
Jamaica Population Growth
0
500000
1000000
1500000
2000000
2500000
3000000
Year
Po
pu
lati
on
Population Growth cont’d
Environmental Resistance
- all the factors jointly acting to limit the growth of a population
Carrying Capacity
- number of individuals of a given species that can be sustained indefinitely in a given area
S-shaped Growth Curve
Time
Num
ber
of I
ndiv
idua
l O
rgan
ism
s
Carrying Capacity
A population grows exponentially until it is acted on by limiting factors that cause the growth to level off at the carrying capacity.
Regulation of Population Size
Density Dependent Checks on Population Growth
- where some limiting factors become more influential as a population’s density increases
- examples:
• competition for resources
• predation
• parasitism
• disease
Regulation of Population Size
Density Independent Checks on Population Growth
- exert their effects on population regardless of population density
- examples:
• floods
• hurricanes
• severe droughts
• fire
• temperature
Overpopulation
- occurs when people exceed the carrying capacity of an area
- more people than can live on Earth or a geographic region in comfort, health & happiness
- also called environmental unsustainability
- leaves the planet or region unfit for future generations
Overpopulation cont’d
There are 2 types of overpopulation:
1. People Overpopulation
2. Consumption Overpopulation
People Overpopulation
- there are more people in the world or in a geographic region than available vital resources can support
- causes the absolute poverty of 1.2 billion people each year in Less Developed Countries
- causes 40 million people in Less Developed Countries to die prematurely each year
Consumption Overpopulation
- high rates of resource use per person
- high levels of pollution and environmental degradation per person
- exists in More Developed Countries, where 1/5 of the world’s people cause significant resource depletion
Factors Affecting Population Growth
- Migration
- Birth Rate - Economic Rewards/Penalties - religion, culture- Empowering Women - average marriage age- Family Planning - children as part of labour force
- Death Rate- AIDS - better nutrition- Crime - availability of good health care
- Economic Development
Source: CIA World Factbook
2001 Population Data For Selected Countries
Country Population Births
Per 1000
Pop.
Deaths
Per 1000 Pop.
Net Migration
Per 1000 Pop.
Population Change
Per 1000 Pop.
Aids Deaths
in 1999
Per 1000 Pop.
(Adult prevalence)
Botswana 1,586,119 28.85 24.18 0 4.7 15.13
(35.8%)
Haiti 6,964,549 31.68 15 -2.64 14 3.3
(5.17%)
Jamaica 2,665,636 18.12 5.48 -7.52 5.1 0.24
(1.2%)
Barbados 275,330 13.47 8.53 -0.32 4.6 0.47
(1.17%)
United States
278,058,881 14.2 8.7 3.5 9 0.07
(0.61%)
Germany 83,029,536 9.16 10.42 4 2.7 0.007
(0.1%)
Source: CIA World Factbook
2006 Population Data For Selected Countries
Country Population Births
Per 1000
Pop.
Deaths
Per 1000 Pop.
Net Migration
Per 1000 Pop.
Population Change
Per 1000 Pop.
Aids Deaths
in 2003
Per 1000 Pop.
(Adult prevalence)
Botswana 1,639,833 23.08 29.5 6.07 -0.35 21.13
(37.3%)
Haiti 8,308,504 36.44 12.17 -1.31 22.96 3.14
(5.6%)
Jamaica 2,758,124 20.82 6.52 -6.27 8.03 0.33
(1.2%)
Barbados 279,912 12.71 8.67 -0.31 3.73 0.72
(1.5%)
United States
298,444,215 14.14 8.26 3.18 9.06 0.048
(0.6%)
Germany 82,422,299 8.25 10.62 2.18 -0.19 0.008
(0.1%)
Source: CIA World Factbook
2011 Population Data For Selected Countries
Country Population Births
Per 1000
Pop.
Deaths
Per 1000 Pop.
Net Migration
Per 1000 Pop.
Population Change
Per 1000 Pop. (Fert)
Aids Deaths
in 2009
(People living with AIDS)
Botswana 2,065,398 22.31 10.57 4.82 16.56
(2.5)
5,800
(320000)
Haiti 9,719,932 24.4 8.21 -8.32 7.87
(3.07)
7100
(120000)
Jamaica 2,868,380 19.2 6.54 -5.34 7.32
(2.17)
1200
(32000)
Barbados 286,705 12.35 8.39 -0.3 3.66
(1.68)
<100
(2100)
United States
313,232,044 13.83 8.38 4.18 9.63
(2.06)
17000
(1.2 million)
Germany 81,471,834 8.3 10.92 0.54 -2.08
(1.41)
<1000
(67000)
Population Distribution: Urban Living
Urbanisation
- process in which people increasingly move from rural areas to densely populated cities
- Increased density of settlement and/or businesses and other activities over time
Population Distribution: Urban Living
Urbanisation (Cont’d)
- Approximately 50% of the world's population live in urban areas
- Should increase to 80% by 2025
Urbanisation (Cont’d)
Factors affecting urbanisationPull Factors
- Cities are the main centres for new jobs, education, innovation, culture & trade
Push Factors
- Unemployment
- Mechanised agriculture
- Government policies / lack of investments
Effects of Urbanisation include:
• Vegetation Loss
• Urban Microclimate
• Water Demands, Increased Runoff & Flooding
• Solid Waste and Pollution
• Noise Pollution
• Land Conversion & Social Disruption
Improving Urban Life (Some Solutions)
• reduce population growth
• increase investments & social services in
rural areas
• repair and revitalise existing cities
• grow food in abandoned lots & community
garden plots
Legislations1. Natural Resources Conservation Authority Act
- Established the NRCA with mandate to ensure effective management of the physical environment of Jamaica
- Developments over a certain size require a permit but does not necessarily require an EIA or the need to consult with potentially affected communities
- In 2001 NRCA merged with the Town and Country Planning Department and the Land Development and Utilization Commission to form the National Environment and Planning Agency
Legislations cont’d
2. Town and Country Planning Act- primary law governing land use in Jamaica
- Development orders indicate what type of development may take place in an area.
- Developments that originate from Government do not require planning permission.
- There is no third party right of appeal.