Human Populations Around The World

As we have talked before, the resources of Earth are unequally shared between the organisms of human population. Of course all of these is influenced by the three spheres (social, economical and environmental)

Human Development Index

Adopted by the UN Development Programme as a measure of the well-being of a country.

Combines measurements of:

• Education
• Life expectance
• Standards of living
• Income
• GDP per capita (Gross Domestic Product)

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Countries might also classified based on their industrial development and GDP

MEDCs (used by modern geographers to specifically describe the status of the countries referred to: more economically developed)

• industrialized nations
• rich population small poverty
• high level of resource use per capita
• relatively low population growth rates

LEDCs  (less economically developed)

• less industrialized 
• natural capital unprocessed
• lower GDP and poverty rates
• Large population sector with low standard of living
• High population growth rates

The Biodiversity Roll.

" Biodiversity is the variety of life

and its processes; and it includes the variety

of living organisms, the genetic differences

among them, and the communities and

ecosystems in which they occur.”

Biodiversity is the amount of the different species, plants and animals, that can be found within an ecosystem, biome or the entire Earth.

The biodiversity index help us to determine the amount of species in a given area. A very simple index goes as the following example:

the number of species in the area (numerator) ----------------------------------------------------------------------- the total number of individuals in the area (denominator )

= biodiversity index

The previous example is very basic. It might be used when little information is available and the experience of the analyst is limited. In order to carry out a better measurement of biodiversity is important to don't include only the number of species, but also the abundance of each specie.

In simple terms the main two aspects are the richness and the evenness.

Richness of species affect more directly the amount of biodiversity than the evenness.

The Simpsons Diversity index covers those two. It can actually refer to any one of 3 closely related indices:

where S is the number of species, N is the total percentage cover or total number of organisms and n is the percentage cover of a species or number of organisms of a species. In this form, D ranges from 1 to 0, with 1 representing infinite diversity and 0 representing no diversity.

Another widely used index is the Shannon index of diversity. It turns out to be poorer than other indices on most criteria:

p_i = the proportion of individuals of species i in the sample, p_i = n_i/N.

I_Shannon = H = - Σ p_i ln(p_i)

The importance of these indices lies on:

• Understanding community structure.
• Outline odd behaviors
• Identify the rarity and commonness of an specie within a community

References.

"How to Calculate a Biodiversity Index." American Museum of Natural Art, n.d. Web. 17 Aug 2010. .

http://www.wcsmalaysia.org/analysis/diversityIndexMenagerie.htm

http://www.countrysideinfo.co.uk/simpsons.htm

http://en.wikipedia.org/wiki/Simpson_index

http://ma.caudillweb.com/documents/bridging/papers/yue.tianxiang.pdf