Demography is the statistical study of populations, especially human beings.
The word "longevity" is sometimes used as a synonym for "life expectancy" in demography. However, the term longevity is sometimes meant to refer only to especially long-lived members of a population, whereas life expectancy is always defined statistically as the average number of years remaining at a given age. For example, a population's life expectancy at birth is the same as the average age at death for all people born in the same year. Longevity is best thought of as a term for general audiences meaning 'typical length of life' and specific statistical definitions should be clarified when necessary.
Maximum life span is a measure of the maximum amount of time one or more members of a population have been observed to survive between birth and death. The term can also denote an estimate of the maximum amount of time that a member of a given species could survive between birth and death, provided circumstances that are optimal to that member's longevity.
The USC Leonard Davis School of Gerontology is one of the seventeen academic divisions of the University of Southern California in Los Angeles, focusing in undergraduate and graduate programs in gerontology,
Longevity claims are unsubstantiated cases of asserted human longevity. Those asserting lifespans of 110 years or more are referred to as supercentenarians. Many have either no official verification or are backed only by partial evidence. Cases where longevity has been fully verified, according to modern standards of longevity research, are reflected in an established list of supercentenarians based on the work of organizations such as the Gerontology Research Group (GRG) or Guinness World Records. This article lists living claims greater than that of the oldest living person whose age has been independently verified, Kane Tanaka at 119 years, 18 days, and deceased claims greater than that of the oldest person ever whose age has been verified, namely Jeanne Calment who died at the age of 122 years, 164 days. The upper limit for both lists is 130 years.
Life history theory is an analytical framework designed to study the diversity of life history strategies used by different organisms throughout the world, as well as the causes and results of the variation in their life cycles. It is a theory of biological evolution that seeks to explain aspects of organisms' anatomy and behavior by reference to the way that their life histories—including their reproductive development and behaviors, post-reproductive behaviors, and lifespan —have been shaped by natural selection. A life history strategy is the "age- and stage-specific patterns" and timing of events that make up an organism's life, such as birth, weaning, maturation, death, etc. These events, notably juvenile development, age of sexual maturity, first reproduction, number of offspring and level of parental investment, senescence and death, depend on the physical and ecological environment of the organism.
Stuart Jay Olshansky is a professor in the School of Public Health at the University of Illinois at Chicago concentrating on biodemography and gerontology and is co-founder and Chief Scientist at Lapetus Solutions, Inc.
Biodemography is a multidisciplinary approach, integrating biological knowledge with demographic research on human longevity and survival. Biodemographic studies are important for understanding the driving forces of the current longevity revolution, forecasting the future of human longevity, and identification of new strategies for further increase in healthy and productive life span.
The reliability theory of aging is an attempt to apply the principles of reliability theory to create a mathematical model of senescence. The theory was published in Russian by Leonid A. Gavrilov and Natalia S. Gavrilova as Biologiia prodolzhitelʹnosti zhizni in 1986, and in English translation as The Biology of Life Span: A Quantitative Approach in 1991.
The compensation law of mortality states that the relative differences in death rates between different populations of the same biological species decrease with age, because the higher initial death rates in disadvantaged populations are compensated by lower pace of mortality increase with age. The age at which this imaginary (extrapolated) convergence of mortality trajectories takes place is named the "species-specific life span". For human beings, this human species-specific life span is close to 95 years.
The Gompertz–Makeham law states that the human death rate is the sum of an age-dependent component, which increases exponentially with age and an age-independent component. In a protected environment where external causes of death are rare, the age-independent mortality component is often negligible. In this case the formula simplifies to a Gompertz law of mortality. In 1825, Benjamin Gompertz proposed an exponential increase in death rates with age.
Enquiry into the evolution of ageing aims to explain why a detrimental process such as aging would evolve, and why there is so much variability in the lifespans of organisms. The classical theories of evolution suggest that environmental factors, such as predation, accidents, disease, starvation, ensure that most organisms living in natural settings will not live until old age, and so there will be very little pressure to conserve genetic changes that increase longevity. Natural selection will instead strongly favor genes which ensure early maturation and rapid reproduction, and the selection for genetic traits which promote molecular and cellular self-maintenance will decline with age for most organisms.
James W. Vaupel, is an American scientist in the fields of aging research, biodemography, and formal demography. He has been instrumental in developing and advancing the idea of the plasticity of longevity, and pioneered research on the heterogeneity of mortality risks and on the deceleration of death rates at the highest ages.
Lloyd A. Demetrius is an American mathematician and theoretical biologist at the Max Planck Institute for Molecular Genetics at Berlin, Germany, and the Department of Organismic and Evolutionary biology, Harvard University. He is best known for the discovery of the concept, evolutionary entropy, a statistical parameter that characterizes Darwinian fitness in models of evolutionary processes at various levels of biological organization – molecular, organismic and cultural. Evolutionary entropy, an analogue of the Gibbs-Boltzmann entropy in statistical physics, is the cornerstone of directionality theory, an analytical study of evolution by variation and selection. The theory has applications to: a) the development of aging and the evolution of longevity; b) the origin and progression of age related diseases such as cancer, and neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease; c) the evolution of cooperation and the spread of inequality.
In gerontology, late-life mortality deceleration is the disputed theory that hazard rate increases at a decreasing rate in late life rather than increasing exponentially as in the Gompertz law.
The Human Mortality Database (HMD) is a joint initiative of the Department of Demographics at the University of California, Berkeley in the United States and the Max Planck Institute for Demographic Research in Rostock, Germany that provides detailed mortality and population data to researchers, students, journalists, policy analysts, and others interested in the history of human longevity. The key people involved are John R. Wilmoth (Director) from the University of California, Berkeley, Vladimir Shkolnikov (Co-Director) from Max Planck Institute for Demographic Research, and Magali Barbieri from the University of California, Berkeley, and INED, Paris.
Social Bonding and Nurture Kinship: Compatibility between Cultural and Biological Approaches is a book on human kinship and social behavior by Maximilian Holland, published in 2012. The work synthesizes the perspectives of evolutionary biology, psychology and sociocultural anthropology towards understanding human social bonding and cooperative behavior. It presents a theoretical treatment that many consider to have resolved longstanding questions about the proper place of genetic connections in human kinship and social relations, and a synthesis that "should inspire more nuanced ventures in applying Darwinian approaches to sociocultural anthropology". The book has been called "A landmark in the field of evolutionary biology" which "gets to the heart of the matter concerning the contentious relationship between kinship categories, genetic relatedness and the prediction of behavior", "places genetic determinism in the correct perspective" and serves as "a shining example of what can be achieved when excellent scholars engage fully across disciplinary boundaries."
The following outline is provided as an overview of and topical guide to evolution:
Human reproductive ecology is a subfield in evolutionary biology that is concerned with human reproductive processes and responses to ecological variables. It is based in the natural and social sciences, and is based on theory and models deriving from human and animal biology, evolutionary theory, and ecology. It is associated with fields such as evolutionary anthropology and seeks to explain human reproductive variation and adaptations. The theoretical orientation of reproductive ecology applies the theory of natural selection to reproductive behaviors, and has also been referred to as the evolutionary ecology of human reproduction.
The mutation accumulation theory of ageing was first proposed by Peter Medawar in 1952 as an evolutionary explanation for biological ageing and the associated decline in fitness that accompanies it. Medawar used the term 'senescence' to refer to this process. The theory explains that, in the case where harmful mutations are only expressed later in life, when reproduction has ceased and future survival is increasingly unlikely, then these mutations are likely to be unknowingly passed on to future generations. In this situation the force of natural selection will be weak, and so insufficient to consistently eliminate these mutations. Medawar posited that over time these mutations would accumulate due to genetic drift and lead to the evolution of what is now referred to as ageing.
