Human Geography Resources and Population

Human Geography Resources and Population

Crude Population Rates

Crude population rate, gross reproduction rate or birth rate, in demography, sociology and geography of the population, is a measure of quantification of fertility, which refers to the relationship between the number of births in a period and the total strength of the same period. The length is almost always a year, and can be read as a number of births per thousand population in a year. It has the advantage of being a simple and easy to interpret, but suffers from some difficulties, as in the comparison between countries can yield differences that are more dependent on the structure by age and sex of the population of the fecundity of the populations analyzed. For this purpose we recommend using refined rates as the total fertility rate or the age structure of fertility.

Logistic Growth Curve

Growth in a population that follows a sigmoid, or S-shaped, growth curve in which growth is initially slow (the lag phase) followed by a period of rapid growth (an exponential growth phase) and then levels off (the stationary growth phase) when the population reaches the carrying capacity of the environment. The logistic growth curve assumes that there is a limit to the maximum size of a population.

The logistic curve or S-shaped curve is a mathematical function that appears in various models of population growth, propagation and dissemination of epidemic diseases in social networks. This function is a refinement of the exponential model for the growth of a magnitude.

The logistic growth is related to the exponential growth, indeed for small values ??of the magnitude that presents logistic growth, logistic growth is very similar to exponential growth. However, from a certain point the growth slows down, it makes the curve can adequately represent the spread of rumors, the extension of a technological innovation or an epidemic: initially these spread quickly, each "infected" or " affected "by the innovation is likely to pass the" contagion "to another individual who has contact with him, but when the number of" infected "grows more difficult to find a person who has not previously been in contact with the disease or innovation.

Exponential Population Growth

Changed to a stock per unit of time a fixed percentage of the value thus always changing, we call this process exponentially, both in the increase (the growth), or (also known as decay or negative growth) of the decrease. Said fixed percentage we call growth. Mathematically, this is exponential process by a exponential function described. Changes however, a stock per unit of time is a non-changing value, we call this linear growth.

Survivorship Curves

Graphs of numbers of individuals in a cohort plotted up the y-axis (usual units log 10 Ix, where Ix is the proportion of the original cohort still alive) from the time they become independent until the time they die, plotted against time (x-axis). Pearl's (1928) classification identifies three commonly occurring curves (I, convex; II, flat; III, concave), representing the consequences of different age dependent ...