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Population viability analysis (PVA) is a species-specific method of risk assessment frequently used in conservation biology.It is traditionally defined as the process that determines the probability that a population will go extinct within a given number of years.
As a consequence, it is an interdisciplinary concept, but maintains biological roots. The hierarchical organizations that are inherent to both biology (cell, organ, individual) and demography (individual cohort, population) form a chain in which the individual serves as the link between the lower mechanistic levels, and the higher functional ...
A reduction in the fitness (biology) of a population is a direct consequence of its low diversity which is dependent on the expression of deleterious recessive alleles. In large populations, natural selection keeps such alleles at a low frequency. Since they usually occur in heterozygotes, they are masked by a copy of “normal alleles”.
The Demography of the World Population from 1950 to 2100. Data source: United Nations — World Population Prospects 2017. Demography (from Ancient Greek δῆμος (dêmos) 'people, society' and -γραφία (-graphía) 'writing, drawing, description') [1] is the statistical study of human populations: their size, composition (e.g., ethnic group, age), and how they change through the ...
Whether migration increases population fitness will depend if the genes brought in are adapted to local conditions and if they decrease levels of inbreeding in the target population. An Introduced individuals can also positively or negatively affect genetic rescue through behaviors such as mate choice , dominance hierarchies, and infanticide.
A demographic structure of a population is how populations are often quantified. The total number of individuals in a population is defined as a population size, and how dense these individuals are is defined as population density. There is also a population's geographic range, which has limits that a species can tolerate (such as temperature).
Minimum viable population (MVP) is a lower bound on the population of a species, such that it can survive in the wild. This term is commonly used in the fields of biology , ecology , and conservation biology .
In ecology, a population is a group of organisms of the same species which inhabit the same geographical area and are capable of interbreeding. [2] [3] The area of a sexual population is the area where interbreeding is possible between any opposite-sex pair within the area and more probable than cross-breeding with individuals from other areas.