POPULATION AND THE ENVIRONMENT

1. POPULATION AND THE ENVIRONMENT

2. 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

3. Population Growthcont’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

4. Population Growthcont’d Population Size - the number of individuals making up a population Population size changes due to: • births • deaths • immigration • emigration

5. Population Growthcont’d Birth Rate (b) - also called crude birth rate - number of birthsper 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

6. Fertility Rate • The number of children born to a woman • Jamaica’s fertility rate is 2.41

7. Replacement Fertility Rate • The fertility rate that is high enough to replace an area's population. • In Industrialised countries it is 2.1

8. Population Growthcont’d Immigration (i) - movement of individuals into a population Emigration (e) - movement of individuals out of a population

9. Population Growthcont’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

10. Population Growthcont’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

11. Exponential Growthcont’d J-shaped Growth Curve

13. Population Growthcont’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

14. S-shaped Growth Curve 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. Number of Individual Organisms Time

15. 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

16. 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

17. Overpopulation • occurs when peopleexceed 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

18. Overpopulationcont’d There are 2 types of overpopulation: 1. People Overpopulation 2. Consumption Overpopulation

19. 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

20. 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

21. 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

22. 2001 Population Data For Selected Countries Source: CIA World Factbook

23. 2006 Population Data For Selected Countries Source: CIA World Factbook

24. 2011 Population Data For Selected Countries Source: CIA World Factbook

25. 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

26. Population Distribution: Urban Living Urbanisation (Cont’d) - Approximately 50% of the world's population live in urban areas - Should increase to 80% by 2025

27. Urbanisation (Cont’d) Factors affecting urbanisation Pull Factors - Cities are the main centres for new jobs, education, innovation, culture & trade Push Factors - Unemployment - Mechanised agriculture - Government policies / lack of investments

28. Effects of Urbanisation include: • Vegetation Loss • Urban Microclimate • Water Demands, Increased Runoff & Flooding • Solid Waste and Pollution • Noise Pollution • Land Conversion & Social Disruption

29. 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

30. Legislations • 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

31. 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.