Why is physiological population density more helpful than arithmetic population density?
|
Show Remember the earlier comparison of Russia and Bangladesh? This is the section where we discuss the different ways of calculating the pressure that populations put onto the land that they inhabit. You’ll recall that we began by looking simply at people per country. This is a good way to start, but the limitations are fairly obvious. Countries that are physically larger can hold more people. We need to use a method that changes from a measure of overall population to some kind of per
capita measure. There are many of these and each has its merits.  Figure 2.17 | Arithmetic Density 201514 Author | David Dorrell Source | Original Work License | CC BY SA 4.0 Physiological density has the same numerator (population), but the denominator is different. Instead of using all the land in a country, it only accounts for arable (farmable) land (Figure 2.18). Places that are not used for agriculture- deserts, lakes, mountaintops and similar places – are subtracted from the land total. This is useful for demonstrating how much pressure is being put on the farmland that is available. Be aware that food that is gathered or hunted from non-agricultural land is not considered in this number. Figure 2.18 | Physiological Density 201515 Author | David Dorrell Source | Original Work License | CC BY SA 4.0 Agricultural density has the same denominator as physiological density, but has a different numerator. Instead of using the entire population, it only uses farmers (Figure 2.19). This provides a number that is a good measure of development, or rather it’s a good measure of underdevelopment. Developed countries have mechanized agriculture and few farmers per capita. Each farm tends to be large in order to generate a sufficient income. Places with high agricultural densities have more farmers per hectare, meaning that farms will likely produce less revenue. Of course, an underlying assumption of this number is the idea that people are growing food to earn a living. If they are eating the produce directly, outside the cash economy, then the comparison is less valid. Figure 2.19 | Agricultural Density 201516 Author | David Dorrell Source | Original Work License | CC BY SA 4.0 Related to food production is the concept of carrying capacity. Carrying capacity is simply how many people can live from a given piece of land. However, it’s not really that simple. Carrying capacity is not static throughout time. Not only do environmental characteristics change (due to desertification, for example) but technology changes as well. The carrying capacity of land in wealthy developed countries has expanded tremendously due to the application of technology. These technologies could be something as simple as irrigation ditches to something as complex as genetic modification of the plants and animals themselves. Carrying capacity is snapshot taken at a particular time. Why is physiological density considered more useful than arithmetic density?The different types of density are each important to understanding a specific area of the world, but physiological density is often considered real population density because it provides a better understanding and overview of the country it relates to.
Why is physiological density useful?Physiological density is the number of persons per unit of agricultural land. This measure of density is useful, because it can give us a rough estimate of how many people an area of farmland can reasonably support. Physiological density is also helpful when studying population pressure and overcrowding.
How is physiological density different from arithmetic density?Arithmetic density, also known as real density, is very simply the total number of people divided by the total land area. Physiological density is the number of people per unit area of arable land. Arable describes land that is suitable for growing crops.
|
