Search results
Results from the WOW.Com Content Network
World population pyramid from 1950 to projected in 2100 (UN, World Population Prospects 2017) A population pyramid (age structure diagram) or "age-sex pyramid" is a graphical illustration of the distribution of a population (typically that of a country or region of the world) by age groups and sex; it typically takes the shape of a pyramid when the population is growing. [1]
For example, oysters produce millions of eggs, but most larvae die from predation or other causes; those that survive long enough to produce a hard shell live relatively long. The number or proportion of organisms surviving to any age is plotted on the y-axis (generally with a logarithmic scale starting with 1000 individuals), while their age ...
An example of using age class structure to learn about a population is a regular bell curve for the population of 1-5 year-old fish with a very low population for the 3-year-olds. An age class structure with gaps in population size like the one described earlier implies a bad spawning year 3 years ago in that species. [ 7 ]
A function f is concave over a convex set if and only if the function −f is a convex function over the set. The sum of two concave functions is itself concave and so is the pointwise minimum of two concave functions, i.e. the set of concave functions on a given domain form a semifield.
Demographic statistics are measures of the characteristics of, or changes to, a population. Records of births, deaths, marriages, immigration and emigration and a regular census of population provide information that is key to making sound decisions about national policy. [1] [2] A useful summary of such data is the population pyramid. It ...
Population geographyis the study of the distribution, composition, migration, and growth of human populations in relation to the geographic characteristics of specific area. It focuses on how populations are distributed across space, the factors influencing these distributions, and the implications for resources, environment, and societal ...
The term convex is often referred to as convex down or concave upward, and the term concave is often referred as concave down or convex upward. [ 3 ] [ 4 ] [ 5 ] If the term "convex" is used without an "up" or "down" keyword, then it refers strictly to a cup shaped graph ∪ {\displaystyle \cup } .
Population pyramid of Uzbekistan in 2023 (Stage three). Population pyramid of Israel in 2023 (Stage three). In Stage 3 of the Demographic Transition Model (DTM), death rates are low and birth rates diminish, as a rule accordingly of enhanced economic conditions, an expansion in women's status and education, and access to contraception.