# Evolutionary suicide

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Evolutionary suicide is an evolutionary phenomenon in which the process of adaptation causes the population to become extinct. For example, individuals might be selected to switch from eating mature plants to seedlings, and thereby deplete their food plant's population. Selection on individuals can theoretically produce adaptations that threaten the survival of the population.

In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection.

Much of the research on evolutionary suicide has used the mathematical modeling technique adaptive dynamics, in which genetic changes are studied together with population dynamics. This allows the model to predict how population density will change as a given trait invades the population.

A mathematical model is a description of a system using mathematical concepts and language. The process of developing a mathematical model is termed mathematical modeling. Mathematical models are used in the natural sciences and engineering disciplines, as well as in the social sciences.

Population dynamics is the branch of life sciences that studies the size and age composition of populations as dynamical systems, and the biological and environmental processes driving them. Example scenarios are ageing populations, population growth, or population decline.

Population density is a measurement of population per unit area or unit volume; it is a quantity of type number density. It is frequently applied to living organisms, and most of the time to humans. It is a key geographical term. In simple terms population density refers to the number of people living in an area per kilometer square.

Evolutionary suicide has also been referred to as "Darwinian extinction", "runaway selection to self-extinction", and "evolutionary collapse".[ citation needed ] The idea is similar in concept to the tragedy of the commons and the Tendency of the rate of profit to fall, namely that they are all examples of an accumulation of individual changes leading to a collective disaster such that it negates those individual changes.

The tragedy of the commons is a term used in environmental science to describe a situation in a shared-resource system where individual users acting independently according to their own self-interest behave contrary to the common good of all users by depleting or spoiling that resource through their collective action. The concept originated in an essay written in 1833 by the British economist William Forster Lloyd, who used a hypothetical example of the effects of unregulated grazing on common land in Great Britain and Ireland. The concept became widely known as the "tragedy of the commons" over a century later due to an article written by the American ecologist and philosopher Garrett Hardin in 1968. In this modern economic context, commons is taken to mean any shared and unregulated resource such as atmosphere, oceans, rivers, fish stocks, roads and highways, or even an office refrigerator.

The tendency of the rate of profit to fall (TRPF) is a hypothesis in economics and political economy, most famously expounded by Karl Marx in chapter 13 of Capital, Volume III. Economists as diverse as Adam Smith, John Stuart Mill, David Ricardo and Stanley Jevons referred explicitly to the TRPF as an empirical phenomenon that demanded further theoretical explanation, yet they each differed as to the reasons why the TRPF should necessarily occur.

Many adaptations have apparently negative effects on population dynamics, for example infanticide by male lions, or the production of toxins by bacteria. However, empirically establishing that an extinction event was unambiguously caused by the process of adaptation is not a trivial task.

The Limits to Growth (LTG) is a 1972 report on the computer simulation of exponential economic and population growth with a finite supply of resources. Funded by the Volkswagen Foundation and commissioned by the Club of Rome, the findings of the study were first presented at international gatherings in Moscow and Rio de Janeiro in the summer of 1971. The report's authors are Donella H. Meadows, Dennis L. Meadows, Jørgen Randers, and William W. Behrens III, representing a team of 17 researchers.

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Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes that are passed on from parent to offspring during reproduction. Different characteristics tend to exist within any given population as a result of mutation, genetic recombination and other sources of genetic variation. Evolution occurs when evolutionary processes such as natural selection and genetic drift act on this variation, resulting in certain characteristics becoming more common or rare within a population. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms and molecules.

Ecology is the branch of biology which studies the interactions among organisms and their environment. Objects of study include interactions of organisms that include biotic and abiotic components of their environment. Topics of interest include the biodiversity, distribution, biomass, and populations of organisms, as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, and the non-living components of their environment. Ecosystem processes, such as primary production, pedogenesis, nutrient cycling, and niche construction, regulate the flux of energy and matter through an environment. These processes are sustained by organisms with specific life history traits. Biodiversity means the varieties of species, genes, and ecosystems, enhances certain ecosystem services.

Theoretical ecology is the scientific discipline devoted to the study of ecological systems using theoretical methods such as simple conceptual models, mathematical models, computational simulations, and advanced data analysis. Effective models improve understanding of the natural world by revealing how the dynamics of species populations are often based on fundamental biological conditions and processes. Further, the field aims to unify a diverse range of empirical observations by assuming that common, mechanistic processes generate observable phenomena across species and ecological environments. Based on biologically realistic assumptions, theoretical ecologists are able to uncover novel, non-intuitive insights about natural processes. Theoretical results are often verified by empirical and observational studies, revealing the power of theoretical methods in both predicting and understanding the noisy, diverse biological world.

Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure.

This is a list of topics in evolutionary biology.

Evolutionary game theory (EGT) is the application of game theory to evolving populations in biology. It defines a framework of contests, strategies, and analytics into which Darwinian competition can be modelled. It originated in 1973 with John Maynard Smith and George R. Price's formalisation of contests, analysed as strategies, and the mathematical criteria that can be used to predict the results of competing strategies.

A metapopulation consists of a group of spatially separated populations of the same species which interact at some level. The term metapopulation was coined by Richard Levins in 1969 to describe a model of population dynamics of insect pests in agricultural fields, but the idea has been most broadly applied to species in naturally or artificially fragmented habitats. In Levins' own words, it consists of "a population of populations".

Evolutionary ecology lies at the intersection of ecology and evolutionary biology. It approaches the study of ecology in a way that explicitly considers the evolutionary histories of species and the interactions between them. Conversely, it can be seen as an approach to the study of evolution that incorporates an understanding of the interactions between the species under consideration. The main subfields of evolutionary ecology are life history evolution, sociobiology, the evolution of inter specific relations and the evolution of biodiversity and of communities.

Brian Carey Goodwin was a Canadian mathematician and biologist, a Professor Emeritus at the Open University and a founder of theoretical biology and biomathematics. He introduced the use of complex systems and generative models in developmental biology. He suggested that a reductionist view of nature fails to explain complex features, controversially proposing the "fringe" structuralist theory that morphogenetic fields might substitute for natural selection in driving evolution. He was also a visible member of the Third Culture movement.

Conservation genetics is an interdisciplinary subfield of Population Genetics that aims to understand the dynamics of genes in populations principally to avoid extinction. Therefore, it applies genetic methods to the conservation and restoration of biodiversity. Researchers involved in conservation genetics come from a variety of fields including population genetics, molecular ecology, biology, evolutionary biology, and systematics. Genetic diversity is one of the three fundamental levels of biodiversity, so it is directly important in conservation. Genetic variability influences both the health and long-term survival of populations because decreased genetic diversity has been associated with reduced fitness, such as high juvenile mortality, diminished population growth, reduced immunity, and ultimately, higher extinction risk.

Dual inheritance theory (DIT), also known as gene–culture coevolution or biocultural evolution, was developed in the 1960s through early 1980s to explain how human behavior is a product of two different and interacting evolutionary processes: genetic evolution and cultural evolution. Genes and culture continually interact in a feedback loop, changes in genes can lead to changes in culture which can then influence genetic selection, and vice versa. One of the theory's central claims is that culture evolves partly through a Darwinian selection process, which dual inheritance theorists often describe by analogy to genetic evolution.

The Red Queen hypothesis, also referred to as Red Queen's, Red Queen's race or the Red Queen effect, is an evolutionary hypothesis which proposes that organisms must constantly adapt, evolve, and proliferate not merely to gain reproductive advantage, but also simply to survive while pitted against ever-evolving opposing organisms in a constantly changing environment. The hypothesis intends to explain two different phenomena: the constant extinction rates as observed in the paleontological record caused by co-evolution between competing species, and the advantage of sexual reproduction at the level of individuals.

Ecological traps are scenarios in which rapid environmental change leads organisms to prefer to settle in poor-quality habitats. The concept stems from the idea that organisms that are actively selecting habitat must rely on environmental cues to help them identify high-quality habitat. If either the habitat quality or the cue changes so that one does not reliably indicate the other, organisms may be lured into poor-quality habitat.

Host–parasite coevolution is a special case of coevolution, the reciprocal adaptive genetic change of a host and a parasite through reciprocal selective pressures.

The following outline is provided as an overview of and topical guide to evolution:

Fluctuating selection is a mode of natural selection characterized by the fluctuation of the direction of selection on a given phenotype over a relatively brief period of evolutionary time. For example, a species of plant may come in two varieties: one which prefers wetter soil and one which prefers dryer soil. During a period of wet years, the wet variety will be more fit and produce more offspring, and thereby increase the frequency of wet-preferring plants. If this wet period is followed by drought, the dry variety will be selected for and its numbers will increase. As periods of dryness and wetness fluctuate, so too does selection on dry-preferring and wet-preferring plants. Fluctuating selection is also manifest at the genic level. Consider two alleles, A and B, which are found at the same locus. Fluctuating selection dynamics are at play when selection favors A at time t0, B at t1 and A again at t2.

The rate of evolution is a variable of considerable interest in evolutionary biology. It concerns the limits of adaptation to natural environments as well as the limits of artificial selection.

Evolutionary rescue is a theoretical situation in which a population recovers from environmental pressure through advantageous genetic change rather than increased gene flow, migration, dispersal or other demographic rescue techniques. While the term was first used in 1995 in Richard Gomulkiewicz and Robert Holt's essay in the journal Evolution, the theory has since academically matured through review and modeling. The most commonly used meaning of the term was established in Gonzalez et al. (2012), which states that evolutionary rescue "occurs when genetic adaptation allows a population to recover from demographic effects initiated by environmental change that would otherwise cause extirpation".