Search results
Results from the WOW.Com Content Network
The rate of natural increase gives demographers an idea of how a region's population is shifting over time. RNI excludes in-migration and out-migration, giving an indication of population growth based only on births and deaths. Comparing natural population change with total population change shows which is dominate for a particular region.
Evolution is the change in the heritable characteristics of biological populations over successive generations. [1] [2] It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. [3]
Biology is the scientific study of life. [ 1 ] [ 2 ] [ 3 ] It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. [ 1 ] [ 2 ] [ 3 ] For instance, all organisms are composed of at least one cell that processes hereditary information encoded in genes , which can be transmitted ...
Resource availability is essential for the unimpeded growth of a population. Examples of resources organisms use are food, water, shelter, sunlight, and nutrients.[1][2] Ideally, when resources in the habitat are unlimited, each species can fully realize its innate potential to grow in number, as Charles Darwin observed while developing his theory of natural selection.
Population momentum impacts the immediate birth and death rates in the population that determine the natural rate of growth. However, for a population to have an absolute zero amount of natural growth, three things must occur. 1. Fertility rates must level off to the replacement rate (the net reproduction rate should be 1). If the fertility ...
Population size can be influenced by the per capita population growth rate (rate at which the population size changes per individual in the population.) Births, deaths, emigration, and immigration rates all play a significant role in growth rate. The maximum per capita growth rate for a population is known as the intrinsic rate of increase.
Achieving ZPG in the short run is difficult because a country's population growth is often determined by economic factors, incidence of poverty, natural disasters, disease, etc. Albert Bartlett, who was a professor of physics at the University of Colorado at Boulder, suggested that a population has the following choices to achieve ZPG: [10]
Biogeography is a synthetic science, related to geography, biology, soil science, geology, climatology, ecology and evolution. Some fundamental concepts in biogeography include: allopatric speciation – the splitting of a species by evolution of geographically isolated populations