title: Attractor

text: Dynamical systems in the physical world tend to arise from dissipative systems: if it were not for some driving force, the motion would cease. (Dissipation may come from internal friction, thermodynamic losses, or loss of material, among many causes.) The dissipation and the driving force tend to balance, killing off initial transients and settle the system into its typical behavior. The subset of the phase space of the dynamical system corresponding to the typical behavior is the attractor, also known as the attracting section or attractee.


title: Attractor

text: Invariant sets and limit sets are similar to the attractor concept. An "invariant set" is a set that evolves to itself under the dynamics. Attractors may contain invariant sets. A "limit set" is a set of points such that there exists some initial state that ends up arbitrarily close to the limit set (i.e. to each point of the set) as time goes to infinity. Attractors are limit sets, but not all limit sets are attractors: It is possible to have some points of a system converge to a limit set, but different points when perturbed slightly off the limit set may get knocked off and never return to the vicinity of the limit set.


title: Attractor

text: For example, the damped pendulum has two invariant points: the point of minimum height and the point of maximum height. The point is also a limit set, as trajectories converge to it; the point is not a limit set. Because of the dissipation due to air resistance, the point is also an attractor. If there was no dissipation, would not be an attractor. Aristotle believed that objects moved only as long as they were pushed, which is an early formulation of a dissipative attractor.


title: Attractor

text: Some attractors are known to be chaotic (see strange attractor), in which case the evolution of any two distinct points of the attractor result in exponentially diverging trajectories, which complicates prediction when even the smallest noise is present in the system.


title: Attractor

text: Let "t" represent time and let "f"("t", •) be a function which specifies the dynamics of the system. That is, if "a" is a point in an "n"-dimensional phase space, representing the initial state of the system, then "f"(0, "a") = "a" and, for a positive value of "t", "f"("t", "a") is the result of the evolution of this state after "t" units of time. For example, if the system describes the evolution of a free particle in one dimension then the phase space is the plane R with coordinates ("x","v"), where "x" is the position of the particle, "v" is its velocity, "a" = ("x","v"), and the evolution is given by


title: Attractor

text: Since the basin of attraction contains an open set containing "A", every point that is sufficiently close to "A" is attracted to "A". The definition of an attractor uses a metric on the phase space, but the resulting notion usually depends only on the topology of the phase space. In the case of R, the Euclidean norm is typically used.


title: Attractor

text: Many other definitions of attractor occur in the literature. For example, some authors require that an attractor have positive measure (preventing a point from being an attractor), others relax the requirement that "B"("A") be a neighborhood.


title: Attractor

text: Attractors are portions or subsets of the phase space of a dynamical system. Until the 1960s, attractors were thought of as being simple geometric subsets of the phase space, like points, lines, surfaces, and simple regions of three-dimensional space. More complex attractors that cannot be categorized as simple geometric subsets, such as topologically wild sets, were known of at the time but were thought to be fragile anomalies. Stephen Smale was able to show that his horseshoe map was robust and that its attractor had the structure of a Cantor set.


title: Attractor

text: Two simple attractors are a fixed point and the limit cycle. Attractors can take on many other geometric shapes (phase space subsets). But when these sets (or the motions within them) cannot be easily described as simple combinations (e.g. intersection and union) of fundamental geometric objects (e.g. lines, surfaces, spheres, toroids, manifolds), then the attractor is called a "strange attractor".


title: Attractor

text: A fixed point of a function or transformation is a point that is mapped to itself by the function or transformation. If we regard the evolution of a dynamical system as a series of transformations, then there may or may not be a point which remains fixed under each transformation. The final state that a dynamical system evolves towards corresponds to an attracting fixed point of the evolution function for that system, such as the center bottom position of a damped pendulum, the level and flat water line of sloshing water in a glass, or the bottom center of a bowl contain a rolling marble. But the fixed point(s) of a dynamic system is not necessarily an attractor of the system. For example, if the bowl containing a rolling marble was inverted and the marble was balanced on top of the bowl, the center bottom (now top) of the bowl is a fixed state, but not an attractor. This is equivalent to the difference between stable and unstable equilibria. In the case of a marble on top of an inverted bowl (a hill), that point at the top of the bowl (hill) is a fixed point (equilibrium), but not an attractor (unstable equilibrium).


title: Attractor

text: In addition, physical dynamic systems with at least one fixed point invariably have multiple fixed points and attractors due to the reality of dynamics in the physical world, including the nonlinear dynamics of stiction, friction, surface roughness, deformation (both elastic and plasticity), and even quantum mechanics. In the case of a marble on top of an inverted bowl, even if the bowl seems perfectly hemispherical, and the marble's spherical shape, are both much more complex surfaces when examined under a microscope, and their shapes change or deform during contact. Any physical surface can be seen to have a rough terrain of multiple peaks, valleys, saddle points, ridges, ravines, and plains. There are many points in this surface terrain (and the dynamic system of a similarly rough marble rolling around on this microscopic terrain) that are considered stationary or fixed points, some of which are categorized as attractors.


title: Attractor

text: In a discrete-time system, an attractor can take the form of a finite number of points that are visited in sequence. Each of these points is called a periodic point. This is illustrated by the logistic map, which depending on its specific parameter value can have an attractor consisting of 1 point, 2 points, 2 points, 3 points, 3×2 points, 4 points, 5 points, or any given positive integer number of points.


title: Attractor

text: A limit cycle is a periodic orbit of a continuous dynamical system that is isolated. It concerns a cyclic attractor. Examples include the swings of a pendulum clock, and the heartbeat while resting. The limit cycle of an ideal pendulum is not an example of a limit cycle attractor because its orbits are not isolated: in the phase space of the ideal pendulum, near any point of a periodic orbit there is another point that belongs to a different periodic orbit, so the former orbit is not attracting. For a physical pendulum under friction, the resting state will be a fixed-point attractor. The difference with the clock pendulum is that there, energy is injected by the escapement mechanism to maintain the cycle.


title: Attractor

text: There may be more than one frequency in the periodic trajectory of the system through the state of a limit cycle. For example, in physics, one frequency may dictate the rate at which a planet orbits a star while a second frequency describes the oscillations in the distance between the two bodies. If two of these frequencies form an irrational fraction (i.e. they are incommensurate), the trajectory is no longer closed, and the limit cycle becomes a limit torus. This kind of attractor is called an -torus if there are incommensurate frequencies. For example, here is a 2-torus:


title: Attractor

text: A time series corresponding to this attractor is a quasiperiodic series: A discretely sampled sum of periodic functions (not necessarily sine waves) with incommensurate frequencies. Such a time series does not have a strict periodicity, but its power spectrum still consists only of sharp lines.


title: Attractor

text: An attractor is called strange if it has a fractal structure. This is often the case when the dynamics on it are chaotic, but strange nonchaotic attractors also exist. If a strange attractor is chaotic, exhibiting sensitive dependence on initial conditions, then any two arbitrarily close alternative initial points on the attractor, after any of various numbers of iterations, will lead to points that are arbitrarily far apart (subject to the confines of the attractor), and after any of various other numbers of iterations will lead to points that are arbitrarily close together. Thus a dynamic system with a chaotic attractor is locally unstable yet globally stable: once some sequences have entered the attractor, nearby points diverge from one another but never depart from the attractor.


title: Attractor

text: The term strange attractor was coined by David Ruelle and Floris Takens to describe the attractor resulting from a series of bifurcations of a system describing fluid flow. Strange attractors are often differentiable in a few directions, but some are like a Cantor dust, and therefore not differentiable. Strange attractors may also be found in the presence of noise, where they may be shown to support invariant random probability measures of Sinai–Ruelle–Bowen type.


title: Attractor

text: Examples of strange attractors include the double-scroll attractor, Hénon attractor, Rössler attractor, and Lorenz attractor.


title: Attractor

text: The parameters of a dynamic equation evolve as the equation is iterated, and the specific values may depend on the starting parameters. An example is the well-studied logistic map, formula_2, whose basins of attraction for various values of the parameter "r" are shown in the figure. If formula_3, all starting "x" values of formula_4 will rapidly lead to function values that go to negative infinity; starting "x" values of formula_5 will also go to negative infinity. But for formula_6 the "x" values rapidly converge to formula_7, i.e. at this value of "r", a single value of "x" is an attractor for the function's behaviour. For other values of "r", more than one value of x may be visited: if "r" is 3.2, starting values of formula_6 will lead to function values that alternate between formula_9 and formula_10. At some values of "r", the attractor is a single point (a "fixed point"), at other values of "r" two values of "x" are visited in turn (a period-doubling bifurcation), or, as a result of further doubling, any number "k" × 2 values of "x"; at yet other values of r, any given number of values of "x" are visited in turn; finally, for some values of "r", an infinitude of points are visited. Thus one and the same dynamic equation can have various types of attractors, depending on its starting parameters.


title: Attractor

text: An attractor's basin of attraction is the region of the phase space, over which iterations are defined, such that any point (any initial condition) in that region will asymptotically be iterated into the attractor. For a stable linear system, every point in the phase space is in the basin of attraction. However, in nonlinear systems, some points may map directly or asymptotically to infinity, while other points may lie in a different basin of attraction and map asymptotically into a different attractor; other initial conditions may be in or map directly into a non-attracting point or cycle.


title: Attractor

text: A single-variable (univariate) linear difference equation of the homogeneous form formula_11 diverges to infinity if |"a"| > 1 from all initial points except 0; there is no attractor and therefore no basin of attraction. But if |"a"| < 1 all points on the number line map asymptotically (or directly in the case of 0) to 0; 0 is the attractor, and the entire number line is the basin of attraction.


title: Attractor

text: Likewise, a linear matrix difference equation in a dynamic vector "X", of the homogeneous form formula_12 in terms of square matrix "A" will have all elements of the dynamic vector diverge to infinity if the largest eigenvalue of "A" is greater than 1 in absolute value; there is no attractor and no basin of attraction. But if the largest eigenvalue is less than 1 in magnitude, all initial vectors will asymptotically converge to the zero vector, which is the attractor; the entire "n"-dimensional space of potential initial vectors is the basin of attraction.


title: Attractor

text: Similar features apply to linear differential equations. The scalar equation formula_13 causes all initial values of "x" except zero to diverge to infinity if "a" > 0 but to converge to an attractor at the value 0 if "a" < 0, making the entire number line the basin of attraction for 0. And the matrix system formula_14 gives divergence from all initial points except the vector of zeroes if any eigenvalue of the matrix "A" is positive; but if all the eigenvalues are negative the vector of zeroes is an attractor whose basin of attraction is the entire phase space.


title: Attractor

text: Equations or systems that are nonlinear can give rise to a richer variety of behavior than can linear systems. One example is Newton's method of iterating to a root of a nonlinear expression. If the expression has more than one real root, some starting points for the iterative algorithm will lead to one of the roots asymptotically, and other starting points will lead to another. The basins of attraction for the expression's roots are generally not simple—it is not simply that the points nearest one root all map there, giving a basin of attraction consisting of nearby points. The basins of attraction can be infinite in number and arbitrarily small. For example, for the function formula_15, the following initial conditions are in successive basins of attraction:


title: Attractor

text: Newton's method can also be applied to complex functions to find their roots. Each root has a basin of attraction in the complex plane; these basins can be mapped as in the image shown. As can be seen, the combined basin of attraction for a particular root can have many disconnected regions. For many complex functions, the boundaries of the basins of attraction are fractals.


title: Attractor

text: Parabolic partial differential equations may have finite-dimensional attractors. The diffusive part of the equation damps higher frequencies and in some cases leads to a global attractor. The "Ginzburg–Landau", the "Kuramoto–Sivashinsky", and the two-dimensional, forced Navier–Stokes equations are all known to have global attractors of finite dimension.


title: Attractor

text: For the three-dimensional, incompressible Navier–Stokes equation with periodic boundary conditions, if it has a global attractor, then this attractor will be of finite dimensions.


title: 1017 Records

text: The New 1017 Records, also known as 1017 Global Music, LLC and formerly 1017 Brick Squad, So Icey Entertainment, & 1017 Eskimo, is an American record label founded by Gucci Mane after his departure from Mizay Entertainment and the closing of So Icey. The label was home to Ralo, Hoodrich Pablo Juan, Waka Flocka Flame, OJ Da Juiceman and others.


title: 1017 Records

text: In 2007 Gucci Mane founded his first independent record label, So Icey Entertainment, after signing with Mizay Entertainment. Soon after Gucci released his independent album, "Trap-A-Thon".


title: 1017 Records

text: From 2007 - 2009, So Icey Entertainment flooded the streets and online streaming platforms with mixtapes. These early years of internet mixtapes would change independent music forever, paving the way for platforms like Youtube, Soundcloud, and Audiomack. Gucci, along with his independent label, So Icey Entertainment, is also responsible birthing legendary trap music names such as: Dj Drama, Gangsta Grillz, The Affiliates, Trap-a-holics Mixtapes, The Empire, Traps-N-Trucks, and much more.


title: 1017 Records

text: On May 4, 2010, he announced that he was closing So Icey Entertainment and leaving Mizay Entertainment due to business concerns with Debra Antney.


title: 1017 Records

text: Gucci Mane then stated that he was starting his own record label (1017 Brick Squad) and that his employer, Jerry Alvarado, was already signing a distribution deal with Asylum Records


title: 1017 Records

text: While still signed to Mizay Entertainment, OJ Da Juiceman and Waka Flocka Flame were first artists signed to "1017 Brick Squad"


title: 1017 Records

text: Juiceman's debut album was unofficially released through the 1017 Brick Squad record label (it was officially released through Asylum Records and Mizay Entertainment). The first mainstream success for 1017 Brick Squad occurred in 2009, when Gucci released "The State vs. Radric Davis".


title: 1017 Records

text: In 2010, Brick Squad artist Waka Flocka Flame released his debut album, "Flockaveli", through Brick Squad, Mizay Entertainment, and Warner Bros.


title: 1017 Records

text: On December 16, 2011, while preparing for a music video at an Atlanta recording studio, Brick Squad artist Slim Dunkin was shot and killed while arguing with another person in the building, later identified as Atlanta rapper Young Vito.


title: 1017 Records

text: On February 25, 2013, Young Vito was acquitted of murdering Slim Dunkin, but he was given a 25-year sentence for aggravated assault and possession of a firearm.


title: 1017 Records

text: On March 15, 2013, via Twitter, Gucci Mane tweeted that he "dropped" Waka Flocka Flame and that Waka was no longer a member of 1017 Brick Squad.


title: 1017 Records

text: The next day, Gucci's management claimed his Twitter account was hacked and he did not send the tweet about Waka Flocka.


title: 1017 Records

text: However, Waka would claim this to be false and later diss Gucci Mane at a Dipset reunion concert in New York City. On March 27, 2013, Waka told MTV that it would be impossible for him to be dropped from 1017 Brick Squad as he owns stake in the company. He also confirmed that there was indeed a feud going on between the rappers and "they would never make music or do business together again."


title: 1017 Records

text: On September 7, 2013, various members of 1017 Brick Squad and Brick Squad Monopoly argued back and forth on Twitter. This was the culmination of a label-wide communication breakdown and spawned Brick Squad Mafia, the label run by Mack Drama which is where Frenchie, along with a multitude of other Brick Squad Artists, first ended up after splitting from the primary group.


title: 1017 Records

text: Mack Drama is also known for being the key to Flocka's street credibility. Mack Drama had the young rapper fly out to meet with other OG Elm Street Pirus, and with a nod by the gang in its original location, by its original founding members, Flocka had his approval for repping the gang. As Mack Drama sided with Gucci Mane in the greater dispute within the label, Mack Drama and Waka Flocka have since part ways from one another. Mack Drama then went on to be the driving force behind artists like Don P (Formerly known as Fatal) and "Vee tha Rula" (who was later signed to Kid Ink), Gucci Mane, Frenchie, Wooh da Kid, and OJ da Juiceman.


title: 1017 Records

text: Gucci Mane would go on to say "fuck brick squad" and accuse his former manager, Waka Flocka's mom Debra Antney, of stealing money from OJ da Juiceman and Frenchie. Frenchie also accused Gucci Mane of paying for Young Vito's lawyer, the accused murderer of former 1017 Brick Squad artist Slim Dunkin, which Gucci denied. Then Frenchie released a diss record toward Gucci the following day.


title: 1017 Records

text: Upon Gucci Mane's latest release from incarceration, he created a new record label, 1017 Eskimo, a partnership venture with Alamo/Empire Distribution. Artists signed to 1017 Eskimo included Hoodrich Pablo Juan and Lil Wop. In 2020, Gucci rebranded his label as 1017 Global Music, LLC, and partnered up with Atlantic to distribute music for his signees. He released a compilation album called "Gucci Mane Presents: So Icy Summer" in July 2020 introducing his artists. He and his label mates released "So Icy Gang Vol.1" in October 2020.


title: Evolution of sexual reproduction

text: Sexual reproduction is an adaptive feature which is common to almost all multicellular organisms and various unicellular organisms, with some organisms being incapable of asexual reproduction. Currently the adaptive advantage of sexual reproduction is widely regarded as a major unsolved problem in biology. As discussed below, one prominent theory is that sex evolved as an efficient mechanism for producing variation, and this had the advantage of enabling organisms to adapt to changing environments. Another prominent theory, also discussed below, is that a primary advantage of outcrossing sex is the masking of the expression of deleterious mutations. Additional theories concerning the adaptive advantage of sex are also discussed below. Sex does, however, come with a cost. In reproducing asexually, no time nor energy needs to be expended in choosing a mate. And if the environment has not changed, then there may be little reason for variation, as the organism may already be well adapted. Sex also halves the amount of offspring a given population is able to produce. Sex, however, has evolved as the most prolific means of species branching into the tree of life. Diversification into the phylogenetic tree happens much more rapidly via sexual reproduction than it does by way of asexual reproduction.


title: Evolution of sexual reproduction

text: Evolution of sexual reproduction describes how sexually reproducing animals, plants, fungi and protists could have evolved from a common ancestor that was a single-celled eukaryotic species. Sexual reproduction is widespread in the Eukarya, though a few eukaryotic species have secondarily lost the ability to reproduce sexually, such as Bdelloidea, and some plants and animals routinely reproduce asexually (by apomixis and parthenogenesis) without entirely having lost sex. The evolution of sex contains two related yet distinct themes: its "origin" and its "maintenance".


title: Evolution of sexual reproduction

text: Although Bacteria and Archaea (prokaryotes) have processes that can transfer DNA from one cell to another (conjugation, transformation, and transduction), these processes are not evolutionarily related to sexual reproduction in Eukaryotes. In eukaryotes, true sexual reproduction by meiosis and cell fusion is thought to have arisen in the last eukaryotic common ancestor, possibly via several processes of varying success, and then to have persisted (compare to "LUCA").


title: Evolution of sexual reproduction

text: Since hypotheses for the origin of sex are difficult to verify experimentally (outside of evolutionary computation), most current work has focused on the persistence of sexual reproduction over evolutionary time. The maintenance of sexual reproduction (specifically, of its dioecious form) by natural selection in a highly competitive world has long been one of the major mysteries of biology, since both other known mechanisms of reproduction – asexual reproduction and hermaphroditism – possess apparent advantages over it. Asexual reproduction can proceed by budding, fission, or spore formation and does not involve the union of gametes, which accordingly results in a much faster rate of reproduction compared to sexual reproduction, where 50% of offspring are males and unable to produce offspring themselves. In hermaphroditic reproduction, each of the two parent organisms required for the formation of a zygote can provide either the male or the female gamete, which leads to advantages in both size and genetic variance of a population.


title: Evolution of sexual reproduction

text: Sexual reproduction therefore must offer significant fitness advantages because, despite the two-fold cost of sex (see below), it dominates among multicellular forms of life, implying that the fitness of offspring produced by sexual processes outweighs the costs. Sexual reproduction derives from recombination, where parent genotypes are reorganized and shared with the offspring. This stands in contrast to single-parent asexual replication, where the offspring is always identical to the parents (barring mutation). Recombination supplies two fault-tolerance mechanisms at the molecular level: "recombinational DNA repair" (promoted during meiosis because homologous chromosomes pair at that time) and "complementation" (also known as heterosis, hybrid vigor or masking of mutations).


title: Evolution of sexual reproduction

text: Reproduction, including modes of sexual reproduction, features in the writings of Aristotle; modern philosophical-scientific thinking on the problem dates from at least Erasmus Darwin (1731–1802) in the 18th century. August Weismann picked up the thread in 1885, arguing that sex serves to generate genetic variation, as detailed in the majority of the explanations below. On the other hand, Charles Darwin (1809–1882) concluded that the effect of hybrid vigor (complementation) "is amply sufficient to account for the … genesis of the two sexes". This is consistent with the repair and complementation hypothesis, described below. Since the emergence of the modern evolutionary synthesis in the 20th century, numerous biologists including W. D. Hamilton, Alexey Kondrashov, George C. Williams, Harris Bernstein, Carol Bernstein, Michael M. Cox, Frederic A. Hopf and Richard E. Michod – have suggested competing explanations for how a vast array of different living species maintain sexual reproduction.


title: Evolution of sexual reproduction

text: The concept of sex includes two fundamental phenomena: the sexual process (fusion of genetic information of two individuals) and sexual differentiation (separation of this information into two parts). Depending on the presence or absence of these phenomena, all of the existing forms of reproduction can be classified as asexual, hermaphrodite or dioecious. The sexual process and sexual differentiation are different phenomena, and, in essence, are diametrically opposed. The first creates (increases) diversity of genotypes, and the second decreases it by half.


title: Evolution of sexual reproduction

text: Reproductive advantages of the asexual forms are in quantity of the progeny, and the advantages of the hermaphrodite forms are in maximal diversity. Transition from the hermaphrodite to dioecious state leads to a loss of at least half of the diversity. So, the primary challenge is to explain the advantages given by sexual differentiation, i.e. the benefits of two separate sexes compared to hermaphrodites rather than to explain benefits of sexual forms (hermaphrodite + dioecious) over asexual ones. It has already been understood that since sexual reproduction is not associated with any clear reproductive advantages, as compared with asexual, there should be some important advantages in evolution.


title: Evolution of sexual reproduction

text: For the advantage due to genetic variation, there are three possible reasons this might happen. First, sexual reproduction can combine the effects of two beneficial mutations in the same individual (i.e. sex aids in the spread of advantageous traits). Also, the necessary mutations do not have to have occurred one after another in a single line of descendants. Second, sex acts to bring together currently deleterious mutations to create severely unfit individuals that are then eliminated from the population (i.e. sex aids in the removal of deleterious genes). However, in organisms containing only one set of chromosomes, deleterious mutations would be eliminated immediately, and therefore removal of harmful mutations is an unlikely benefit for sexual reproduction. Lastly, sex creates new gene combinations that may be more fit than previously existing ones, or may simply lead to reduced competition among relatives.


title: Evolution of sexual reproduction

text: For the advantage due to DNA repair, there is an immediate large benefit of removing DNA damage by recombinational DNA repair during meiosis, since this removal allows greater survival of progeny with undamaged DNA. The advantage of complementation to each sexual partner is avoidance of the bad effects of their deleterious recessive genes in progeny by the masking effect of normal dominant genes contributed by the other partner.


title: Evolution of sexual reproduction

text: The classes of hypotheses based on the creation of variation are further broken down below. Any number of these hypotheses may be true in any given species (they are not mutually exclusive), and different hypotheses may apply in different species. However, a research framework based on creation of variation has yet to be found that allows one to determine whether the reason for sex is universal for all sexual species, and, if not, which mechanisms are acting in each species.


title: Evolution of sexual reproduction

text: On the other hand, the maintenance of sex based on DNA repair and complementation applies widely to all sexual species.


title: Evolution of sexual reproduction

text: In contrast to the view that sex promotes genetic variation, Heng, and Gorelick and Heng reviewed evidence that sex actually acts as a constraint on genetic variation. They consider that sex acts as a coarse filter, weeding out major genetic changes, such as chromosomal rearrangements, but permitting minor variation, such as changes at the nucleotide or gene level (that are often neutral) to pass through the sexual sieve.


title: Evolution of sexual reproduction

text: Sex could be a method by which novel genotypes are created. Because sex combines genes from two individuals, sexually reproducing populations can more easily combine advantageous genes than can asexual populations. If, in a sexual population, two different advantageous alleles arise at different loci on a chromosome in different members of the population, a chromosome containing the two advantageous alleles can be produced within a few generations by recombination. However, should the same two alleles arise in different members of an asexual population, the only way that one chromosome can develop the other allele is to independently gain the same mutation, which would take much longer. Several studies have addressed counterarguments, and the question of whether this model is sufficiently robust to explain the predominance of sexual versus asexual reproduction remains.


title: Evolution of sexual reproduction

text: Ronald Fisher also suggested that sex might facilitate the spread of advantageous genes by allowing them to better escape their genetic surroundings, if they should arise on a chromosome with deleterious genes.


title: Evolution of sexual reproduction

text: Supporters of these theories respond to the balance argument that the individuals produced by sexual and asexual reproduction may differ in other respects too – which may influence the persistence of sexuality. For example, in the heterogamous water fleas of the genus "Cladocera", sexual offspring form eggs which are better able to survive the winter versus those the fleas produce asexually.


title: Evolution of sexual reproduction

text: One of the most widely discussed theories to explain the persistence of sex is that it is maintained to assist sexual individuals in resisting parasites, also known as the Red Queen Hypothesis.


title: Evolution of sexual reproduction

text: When an environment changes, previously neutral or deleterious alleles can become favourable. If the environment changed sufficiently rapidly (i.e. between generations), these changes in the environment can make sex advantageous for the individual. Such rapid changes in environment are caused by the co-evolution between hosts and parasites.


title: Evolution of sexual reproduction

text: Imagine, for example that there is one gene in parasites with two alleles "p" and "P" conferring two types of parasitic ability, and one gene in hosts with two alleles "h" and "H", conferring two types of parasite resistance, such that parasites with allele "p" can attach themselves to hosts with the allele "h", and "P" to "H". Such a situation will lead to cyclic changes in allele frequency – as "p" increases in frequency, "h" will be disfavoured.


title: Evolution of sexual reproduction

text: In reality, there will be several genes involved in the relationship between hosts and parasites. In an asexual population of hosts, offspring will only have the different parasitic resistance if a mutation arises. In a sexual population of hosts, however, offspring will have a new combination of parasitic resistance alleles.


title: Evolution of sexual reproduction

text: In other words, like Lewis Carroll's Red Queen, sexual hosts are continually "running" (adapting) to "stay in one place" (resist parasites).


title: Evolution of sexual reproduction

text: Evidence for this explanation for the evolution of sex is provided by comparison of the rate of molecular evolution of genes for kinases and immunoglobulins in the immune system with genes coding other proteins. The genes coding for immune system proteins evolve considerably faster.


title: Evolution of sexual reproduction

text: Further evidence for the Red Queen hypothesis was provided by observing long-term dynamics and parasite coevolution in a "mixed" (sexual and asexual) population of snails ("Potamopyrgus antipodarum"). The number of sexuals, the number asexuals, and the rates of parasite infection for both were monitored. It was found that clones that were plentiful at the beginning of the study became more susceptible to parasites over time. As parasite infections increased, the once plentiful clones dwindled dramatically in number. Some clonal types disappeared entirely. Meanwhile, sexual snail populations remained much more stable over time.


title: Evolution of sexual reproduction

text: However, Hanley et al. studied mite infestations of a parthenogenetic gecko species and its two related sexual ancestral species. Contrary to expectation based on the Red Queen hypothesis, they found that the prevalence, abundance and mean intensity of mites in sexual geckos was significantly higher than in asexuals sharing the same habitat.


title: Evolution of sexual reproduction

text: In 2011, researchers used the microscopic roundworm "Caenorhabditis elegans" as a host and the pathogenic bacteria "Serratia marcescens" to generate a host-parasite coevolutionary system in a controlled environment, allowing them to conduct more than 70 evolution experiments testing the Red Queen Hypothesis. They genetically manipulated the mating system of "C. elegans", causing populations to mate either sexually, by self-fertilization, or a mixture of both within the same population. Then they exposed those populations to the "S. marcescens" parasite. It was found that the self-fertilizing populations of "C. elegans" were rapidly driven extinct by the coevolving parasites while sex allowed populations to keep pace with their parasites, a result consistent with the Red Queen Hypothesis. In natural populations of "C. elegans", self-fertilization is the predominant mode of reproduction, but infrequent out-crossing events occur at a rate of about 1%.


title: Evolution of sexual reproduction

text: Critics of the Red Queen hypothesis question whether the constantly changing environment of hosts and parasites is sufficiently common to explain the evolution of sex. In particular, Otto and Nuismer presented results showing that species interactions (e.g. host vs parasite interactions) typically select against sex. They concluded that, although the Red Queen hypothesis favors sex under certain circumstances, it alone does not account for the ubiquity of sex. Otto and Gerstein further stated that "it seems doubtful to us that strong selection per gene is sufficiently commonplace for the Red Queen hypothesis to explain the ubiquity of sex". Parker reviewed numerous genetic studies on plant disease resistance and failed to uncover a single example consistent with the assumptions of the Red Queen hypothesis.


title: Evolution of sexual reproduction

text: The paradox of the existence of sexual reproduction is that though it is ubiquitous in multicellular organisms, there are ostensibly many inherent disadvantages to reproducing sexually when weighed against the relative advantages of alternative forms of reproduction, such as asexual reproduction. Thus, because sexual reproduction abounds in complex multicellular life, there must be some significant benefit(s) to sex and sexual reproduction that compensates for these fundamental disadvantages.


title: Evolution of sexual reproduction

text: Among the most limiting disadvantages to the evolution of sexual reproduction by natural selection is that an asexual population can grow much more rapidly than a sexual one with each generation.


title: Evolution of sexual reproduction

text: For example, assume that the entire population of some theoretical species has 100 total organisms consisting of two sexes (i.e. males and females), with 50:50 male-to-female representation, and that only the females of this species can bear offspring. If all capable members of this population procreated once, a total of 50 offspring would be produced (the "F" generation). Contrast this outcome with an asexual species, in which each and every member of an equally sized 100-organism population is capable of bearing young. If all capable members of this asexual population procreated once, a total of 100 offspring would be produced – twice as many as produced by the sexual population in a single generation.


title: Evolution of sexual reproduction

text: This idea is sometimes referred to as the two-fold cost of sexual reproduction. It was first described mathematically by John Maynard Smith. In his manuscript, Smith further speculated on the impact of an asexual mutant arising in a sexual population, which suppresses meiosis and allows eggs to develop into offspring genetically identical to the mother by mitotic division. The mutant-asexual lineage would double its representation in the population each generation, all else being equal.


title: Evolution of sexual reproduction

text: Technically the problem above is not one of sexual reproduction but of having a subset of organisms incapable of bearing offspring. Indeed, some multicellular organisms (isogamous) engage in sexual reproduction but all members of the species are capable of bearing offspring. The two-fold reproductive disadvantage assumes that males contribute only genes to their offspring and sexual females waste half their reproductive potential on sons. Thus, in this formulation, the principal cost of sex is that males and females must successfully copulate, which almost always involves expending energy to come together through time and space. Asexual organisms need not expend the energy necessary to find a mate.


title: Evolution of sexual reproduction

text: Sexual reproduction implies that chromosomes and alleles segregate and recombine in every generation, but not all genes are transmitted together to the offspring. There is a chance of spreading mutants that cause unfair transmission at the expense of their non-mutant colleagues. These mutations are referred to as "selfish" because they promote their own spread at the cost of alternative alleles or of the host organism; they include nuclear meiotic drivers and selfish cytoplasmic genes. Meiotic drivers are genes that distort meiosis to produce gametes containing themselves more than the 50% of the time expected by chance. A selfish cytoplasmic gene is a gene located in an organelle, plasmid or intracellular parasite that modifies reproduction to cause its own increase at the expense of the cell or organism that carries it.


title: Evolution of sexual reproduction

text: A sexually reproducing organism only passes on ~50% of its own genetic material to each L2 offspring. This is a consequence of the fact that gametes from sexually reproducing species are haploid. Again, however, this is not applicable to all sexual organisms. There are numerous species which are sexual but do not have a genetic-loss problem because they do not produce males or females. Yeast, for example, are isogamous sexual organisms which have two mating types which fuse and recombine their haploid genomes. Both sexes reproduce during the haploid and diploid stages of their life cycle and have a 100% chance of passing their genes into their offspring.


title: Evolution of sexual reproduction

text: Some species avoid the 50% cost of sexual reproduction, although they have "sex" (in the sense of genetic recombination). In these species (e.g., bacteria, ciliates, dinoflagellates and diatoms), "sex" and reproduction occurs separately.


title: Evolution of sexual reproduction

text: As discussed in the earlier part of this article, sexual reproduction is conventionally explained as an adaptation for producing genetic variation through allelic recombination. As acknowledged above, however, serious problems with this explanation have led many biologists to conclude that the benefit of sex is a major unsolved problem in evolutionary biology.


title: Evolution of sexual reproduction

text: An alternative "informational" approach to this problem has led to the view that the two fundamental aspects of sex, genetic recombination and outcrossing, are adaptive responses to the two major sources of "noise" in transmitting genetic information. Genetic noise can occur as either physical damage to the genome (e.g. chemically altered bases of DNA or breaks in the chromosome) or replication errors (mutations). This alternative view is referred to as the repair and complementation hypothesis, to distinguish it from the traditional variation hypothesis.


title: Evolution of sexual reproduction

text: The repair and complementation hypothesis assumes that genetic recombination is fundamentally a DNA repair process, and that when it occurs during meiosis it is an adaptation for repairing the genomic DNA which is passed on to progeny. Recombinational repair is the only repair process known which can accurately remove double-strand damages in DNA, and such damages are both common in nature and ordinarily lethal if not repaired. For instance, double-strand breaks in DNA occur about 50 times per cell cycle in human cells (see naturally occurring DNA damage). Recombinational repair is prevalent from the simplest viruses to the most complex multicellular eukaryotes. It is effective against many different types of genomic damage, and in particular is highly efficient at overcoming double-strand damages. Studies of the mechanism of meiotic recombination indicate that meiosis is an adaptation for repairing DNA. These considerations form the basis for the first part of the repair and complementation hypothesis.


title: Evolution of sexual reproduction

text: In some lines of descent from the earliest organisms, the diploid stage of the sexual cycle, which was at first transient, became the predominant stage, because it allowed complementation — the masking of deleterious recessive mutations (i.e. hybrid vigor or heterosis). Outcrossing, the second fundamental aspect of sex, is maintained by the advantage of masking mutations and the disadvantage of inbreeding (mating with a close relative) which allows expression of recessive mutations (commonly observed as inbreeding depression). This is in accord with Charles Darwin, who concluded that the adaptive advantage of sex is hybrid vigor; or as he put it, "the offspring of two individuals, especially if their progenitors have been subjected to very different conditions, have a great advantage in height, weight, constitutional vigor and fertility over the self fertilised offspring from either one of the same parents."


title: Evolution of sexual reproduction

text: However, outcrossing may be abandoned in favor of parthenogenesis or selfing (which retain the advantage of meiotic recombinational repair) under conditions in which the costs of mating are very high. For instance, costs of mating are high when individuals are rare in a geographic area, such as when there has been a forest fire and the individuals entering the burned area are the initial ones to arrive. At such times mates are hard to find, and this favors parthenogenic species.


title: Evolution of sexual reproduction

text: In the view of the repair and complementation hypothesis, the removal of DNA damage by recombinational repair produces a new, less deleterious form of informational noise, allelic recombination, as a by-product. This lesser informational noise generates genetic variation, viewed by some as the major effect of sex, as discussed in the earlier parts of this article.


title: Evolution of sexual reproduction

text: Mutations can have many different effects upon an organism. It is generally believed that the majority of non-neutral mutations are deleterious, which means that they will cause a decrease in the organism's overall fitness. If a mutation has a deleterious effect, it will then usually be removed from the population by the process of natural selection. Sexual reproduction is believed to be more efficient than asexual reproduction in removing those mutations from the genome.


title: Evolution of sexual reproduction

text: There are two main hypotheses which explain how sex may act to remove deleterious genes from the genome.


title: Evolution of sexual reproduction

text: While DNA is able to recombine to modify alleles, DNA is also susceptible to mutations within the sequence that can affect an organism in a negative manner. Asexual organisms do not have the ability to recombine their genetic information to form new and differing alleles. Once a mutation occurs in the DNA or other genetic carrying sequence, there is no way for the mutation to be removed from the population until another mutation occurs that ultimately deletes the primary mutation. This is rare among organisms.


title: Evolution of sexual reproduction

text: Hermann Joseph Muller introduced the idea that mutations build up in asexual reproducing organisms. Muller described this occurrence by comparing the mutations that accumulate as a ratchet. Each mutation that arises in asexually reproducing organisms turns the ratchet once. The ratchet is unable to be rotated backwards, only forwards. The next mutation that occurs turns the ratchet once more. Additional mutations in a population continually turn the ratchet and the mutations, mostly deleterious, continually accumulate without recombination. These mutations are passed onto the next generation because the offspring are exact genetic clones of their parents. The genetic load of organisms and their populations will increase due to the addition of multiple deleterious mutations and decrease the overall reproductive success and fitness.


title: Evolution of sexual reproduction

text: For sexually reproducing populations, studies have shown that single-celled bottlenecks are beneficial for resisting mutation build-up. Passaging a population through a single-celled bottleneck involves the fertilization event occurring with haploid sets of DNA, forming one fertilized cell. For example, humans undergo a single-celled bottleneck in that the haploid sperm fertilizes the haploid egg, forming the diploid zygote, which is unicellular. This passage through a single cell is beneficial in that it lowers the chance of mutations from being passed on through multiple individuals. Instead, the mutation is only passed onto one individual. Further studies using "Dictyostelium discoideum" suggest that this unicellular initial stage is important for resisting mutations due to the importance of high relatedness. Highly related individuals are more closely related, and more clonal, whereas less related individuals are less so, increasing the likelihood that an individual in a population of low relatedness may have a detrimental mutation. Highly related populations also tend to thrive better than lowly related because the cost of sacrificing an individual is greatly offset by the benefit gained by its relatives and in turn, its genes, according to kin selection. The studies with "D. discoideum" showed that conditions of high relatedness resisted mutant individuals more effectively than those of low relatedness, suggesting the importance of high relatedness to resist mutations from proliferating.


title: Evolution of sexual reproduction

text: This hypothesis was proposed by Alexey Kondrashov, and is sometimes known as the "deterministic mutation hypothesis". It assumes that the majority of deleterious mutations are only slightly deleterious, and affect the individual such that the introduction of each additional mutation has an increasingly large effect on the fitness of the organism. This relationship between number of mutations and fitness is known as "synergistic epistasis".


title: Evolution of sexual reproduction

text: By way of analogy, think of a car with several minor faults. Each is not sufficient alone to prevent the car from running, but in combination, the faults combine to prevent the car from functioning.


title: Evolution of sexual reproduction

text: Similarly, an organism may be able to cope with a few defects, but the presence of many mutations could overwhelm its backup mechanisms.


title: Evolution of sexual reproduction

text: Kondrashov argues that the slightly deleterious nature of mutations means that the population will tend to be composed of individuals with a small number of mutations. Sex will act to recombine these genotypes, creating some individuals with fewer deleterious mutations, and some with more. Because there is a major selective disadvantage to individuals with more mutations, these individuals die out. In essence, sex compartmentalises the deleterious mutations.


title: Evolution of sexual reproduction

text: There has been much criticism of Kondrashov's theory, since it relies on two key restrictive conditions. The first requires that the rate of deleterious mutation should exceed one per genome per generation in order to provide a substantial advantage for sex. While there is some empirical evidence for it (for example in Drosophila and E. coli), there is also strong evidence against it. Thus, for instance, for the sexual species "Saccharomyces cerevisiae" (yeast) and "Neurospora crassa" (fungus), the mutation rate per genome per replication are 0.0027 and 0.0030 respectively. For the nematode worm "Caenorhabditis elegans", the mutation rate per effective genome per sexual generation is 0.036. Secondly, there should be strong interactions among loci (synergistic epistasis), a mutation-fitness relation for which there is only limited evidence. Conversely, there is also the same amount of evidence that mutations show no epistasis (purely additive model) or antagonistic interactions (each additional mutation has a disproportionally "small" effect).


title: Evolution of sexual reproduction

text: Geodakyan suggested that sexual dimorphism provides a partitioning of a species' phenotypes into at least two functional partitions: a female partition that secures beneficial features of the species and a male partition that emerged in species with more variable and unpredictable environments. The male partition is suggested to be an "experimental" part of the species that allows the species to expand their ecological niche, and to have alternative configurations. This theory underlines the higher variability and higher mortality in males, in comparison to females. This functional partitioning also explains the higher susceptibility to disease in males, in comparison to females and therefore includes the idea of "protection against parasites" as another functionality of male sex. Geodakyan's evolutionary theory of sex was developed in Russia in 1960–1980 and was not known to the West till the era of the Internet. Trofimova, who analysed psychological sex differences, hypothesised that the male sex might also provide a "redundancy pruning" function.


title: Evolution of sexual reproduction

text: Ilan Eshel suggested that sex prevents rapid evolution. He suggests that recombination breaks up favourable gene combinations more often than it creates them, and sex is maintained because it ensures selection is longer-term than in asexual populations – so the population is less affected by short-term changes. This explanation is not widely accepted, as its assumptions are very restrictive.


title: Evolution of sexual reproduction

text: It has recently been shown in experiments with "Chlamydomonas" algae that sex can remove the speed limit on evolution.


title: Evolution of sexual reproduction

text: An information theoretic analysis using a simplified but useful model shows that in asexual reproduction, the information gain per generation of a species is limited to 1 bit per generation, while in sexual reproduction, the information gain is bounded by where formula_1 is the size of the genome in bits.


title: Evolution of sexual reproduction

text: The evolution of sex can alternatively be described as a kind of gene exchange that is independent from reproduction. According to the Thierry Lodé's "libertine bubble theory", sex originated from an archaic gene transfer process among prebiotic bubbles. The contact among the pre-biotic bubbles could, through simple food or parasitic reactions, promote the transfer of genetic material from one bubble to another. That interactions between two organisms be in balance appear to be a sufficient condition to make these interactions evolutionarily efficient, i.e. to select bubbles that tolerate these interactions ("libertine" bubbles) through a blind evolutionary process of self-reinforcing gene correlations and compatibility.


title: Evolution of sexual reproduction

text: The "libertine bubble theory" proposes that meiotic sex evolved in proto-eukaryotes to solve a problem that bacteria did not have, namely a large amount of DNA material, occurring in an archaic step of proto-cell formation and genetic exchanges. So that, rather than providing selective advantages through reproduction, sex could be thought of as a series of separate events which combines step-by-step some very weak benefits of recombination, meiosis, gametogenesis and syngamy. Therefore, current sexual species could be descendants of primitive organisms that practiced more stable exchanges in the long term, while asexual species have emerged, much more recently in evolutionary history, from the conflict of interest resulting from anisogamy.


title: Evolution of sexual reproduction

text: R. Stephen Howard and Curtis Lively were the first to suggest that the combined effects of parasitism and mutation accumulation can lead to an increased advantage to sex under conditions not otherwise predicted (Nature, 1994). Using computer simulations, they showed that when the two mechanisms act simultaneously the advantage to sex over asexual reproduction is larger than for either factor operating alone.


title: Evolution of sexual reproduction

text: Many protists reproduce sexually, as do many multicellular plants, animals, and fungi. In the eukaryotic fossil record, sexual reproduction first appeared about 2.0 billion years ago in the Proterozoic Eon, although a later date, 1.2 billion years ago, has also been presented. Nonetheless, all sexually reproducing eukaryotic organisms likely derive from a single-celled common ancestor. It is probable that the evolution of sex was an integral part of the evolution of the first eukaryotic cell. There are a few species which have secondarily lost this feature, such as Bdelloidea and some parthenocarpic plants.


title: Evolution of sexual reproduction

text: Organisms need to replicate their genetic material in an efficient and reliable manner. The necessity to repair genetic damage is one of the leading theories explaining the origin of sexual reproduction. Diploid individuals can repair a damaged section of their DNA via homologous recombination, since there are two copies of the gene in the cell and if one copy is damaged, the other copy is unlikely to be damaged at the same site.


title: Evolution of sexual reproduction

text: A harmful damage in a haploid individual, on the other hand, is more likely to become fixed (i.e. permanent), since any DNA repair mechanism would have no source from which to recover the original undamaged sequence. The most primitive form of sex may have been one organism with damaged DNA replicating an undamaged strand from a similar organism in order to repair itself.


title: Evolution of sexual reproduction

text: If, as evidence indicates, sexual reproduction arose very early in eukaryotic evolution, the essential features of meiosis may have already been present in the prokaryotic ancestors of eukaryotes. In extant organisms, proteins with central functions in meiosis are similar to key proteins in natural transformation in bacteria and DNA transfer in archaea. For example, recA recombinase, that catalyses the key functions of DNA homology search and strand exchange in the bacterial sexual process of transformation, has orthologs in eukaryotes that perform similar functions in meiotic recombination (see Wikipedia articles RecA, RAD51 and DMC1).


title: Evolution of sexual reproduction

text: Natural transformation in bacteria, DNA transfer in archaea, and meiosis in eukaryotic microorganisms are induced by stressful circumstances such as overcrowding, resource depletion, and DNA damaging conditions. This suggests that these sexual processes are adaptations for dealing with stress, particularly stress that causes DNA damage. In bacteria, these stresses induce an altered physiologic state, termed competence, that allows active take-up of DNA from a donor bacterium and the integration of this DNA into the recipient genome (see Natural competence) allowing recombinational repair of the recipients' damaged DNA.


title: Evolution of sexual reproduction

text: If environmental stresses leading to DNA damage were a persistent challenge to the survival of early microorganisms, then selection would likely have been continuous through the prokaryote to eukaryote transition, and adaptative adjustments would have followed a course in which bacterial transformation or archaeal DNA transfer naturally gave rise to sexual reproduction in eukaryotes.


title: Evolution of sexual reproduction

text: Sex might also have been present even earlier, in the hypothesized RNA world that preceded DNA cellular life forms. One proposed origin of sex in the RNA world was based on the type of sexual interaction that is known to occur in extant single-stranded segmented RNA viruses, such as influenza virus, and in extant double-stranded segmented RNA viruses such as reovirus.


title: Evolution of sexual reproduction

text: Exposure to conditions that cause RNA damage could have led to blockage of replication and death of these early RNA life forms. Sex would have allowed re-assortment of segments between two individuals with damaged RNA, permitting undamaged combinations of RNA segments to come together, thus allowing survival. Such a regeneration phenomenon, known as multiplicity reactivation, occurs in influenza virus and reovirus.


title: Evolution of sexual reproduction

text: Another theory is that sexual reproduction originated from selfish parasitic genetic elements that exchange genetic material (that is: copies of their own genome) for their transmission and propagation. In some organisms, sexual reproduction has been shown to enhance the spread of parasitic genetic elements (e.g. yeast, filamentous fungi).


title: Evolution of sexual reproduction

text: Bacterial conjugation is a form of genetic exchange that some sources describe as "sex", but technically is not a form of reproduction, even though it is a form of horizontal gene transfer. However, it does support the "selfish gene" part theory, since the gene itself is propagated through the F-plasmid.


title: Evolution of sexual reproduction

text: A similar origin of sexual reproduction is proposed to have evolved in ancient haloarchaea as a combination of two independent processes: jumping genes and plasmid swapping.


title: Evolution of sexual reproduction

text: A third theory is that sex evolved as a form of cannibalism: One primitive organism ate another one, but instead of completely digesting it, some of the eaten organism's DNA was incorporated into the DNA of the eater.


title: Evolution of sexual reproduction

text: Sex may also be derived from another prokaryotic process. A comprehensive theory called "origin of sex as vaccination" proposes that eukaryan sex-as-syngamy (fusion sex) arose from prokaryan unilateral sex-as-infection, when infected hosts began swapping nuclearised genomes containing coevolved, vertically transmitted symbionts that provided protection against horizontal superinfection by other, more virulent symbionts.


title: Evolution of sexual reproduction

text: Consequently, sex-as-meiosis (fission sex) would evolve as a host strategy for uncoupling from (and thereby render impotent) the acquired symbiotic/parasitic genes.


title: Evolution of sexual reproduction

text: While theories positing fitness benefits that led to the origin of sex are often problematic, several theories addressing the emergence of the mechanisms of sexual reproduction have been proposed.


title: Evolution of sexual reproduction

text: The viral eukaryogenesis (VE) theory proposes that eukaryotic cells arose from a combination of a lysogenic virus, an archaean, and a bacterium. This model suggests that the nucleus originated when the lysogenic virus incorporated genetic material from the archaean and the bacterium and took over the role of information storage for the amalgam. The archaeal host transferred much of its functional genome to the virus during the evolution of cytoplasm, but retained the function of gene translation and general metabolism. The bacterium transferred most of its functional genome to the virus as it transitioned into a mitochondrion.


title: Evolution of sexual reproduction

text: For these transformations to lead to the eukaryotic cell cycle, the VE hypothesis specifies a pox-like virus as the lysogenic virus. A pox-like virus is a likely ancestor because of its fundamental similarities with eukaryotic nuclei. These include a double stranded DNA genome, a linear chromosome with short telomeric repeats, a complex membrane bound capsid, the ability to produce capped mRNA, and the ability to export the capped mRNA across the viral membrane into the cytoplasm. The presence of a lysogenic pox-like virus ancestor explains the development of meiotic division, an essential component of sexual reproduction.


title: Evolution of sexual reproduction

text: Meiotic division in the VE hypothesis arose because of the evolutionary pressures placed on the lysogenic virus as a result of its inability to enter into the lytic cycle. This selective pressure resulted in the development of processes allowing the viruses to spread horizontally throughout the population. The outcome of this selection was cell-to-cell fusion. (This is distinct from the conjugation methods used by bacterial plasmids under evolutionary pressure, with important consequences.) The possibility of this kind of fusion is supported by the presence of fusion proteins in the envelopes of the pox viruses that allow them to fuse with host membranes. These proteins could have been transferred to the cell membrane during viral reproduction, enabling cell-to-cell fusion between the virus host and an uninfected cell. The theory proposes meiosis originated from the fusion between two cells infected with related but different viruses which recognised each other as uninfected. After the fusion of the two cells, incompatibilities between the two viruses result in a meiotic-like cell division.


title: Evolution of sexual reproduction

text: The two viruses established in the cell would initiate replication in response to signals from the host cell. A mitosis-like cell cycle would proceed until the viral membranes dissolved, at which point linear chromosomes would be bound together with centromeres. The homologous nature of the two viral centromeres would incite the grouping of both sets into tetrads. It is speculated that this grouping may be the origin of crossing over, characteristic of the first division in modern meiosis. The partitioning apparatus of the mitotic-like cell cycle the cells used to replicate independently would then pull each set of chromosomes to one side of the cell, still bound by centromeres. These centromeres would prevent their replication in subsequent division, resulting in four daughter cells with one copy of one of the two original pox-like viruses. The process resulting from combination of two similar pox viruses within the same host closely mimics meiosis.


title: Evolution of sexual reproduction

text: An alternative theory, proposed by Thomas Cavalier-Smith, was labeled the Neomuran revolution. The designation "Neomuran revolution" refers to the appearances of the common ancestors of eukaryotes and archaea. Cavalier-Smith proposes that the first neomurans emerged 850 million years ago. Other molecular biologists assume that this group appeared much earlier, but Cavalier-Smith dismisses these claims because they are based on the "theoretically and empirically" unsound model of molecular clocks. Cavalier-Smith's theory of the Neomuran revolution has implications for the evolutionary history of the cellular machinery for recombination and sex. It suggests that this machinery evolved in two distinct bouts separated by a long period of stasis; first the appearance of recombination machinery in a bacterial ancestor which was maintained for 3 Gy(billion years), until the neomuran revolution when the mechanics were adapted to the presence of nucleosomes. The archaeal products of the revolution maintained recombination machinery that was essentially bacterial, whereas the eukaryotic products broke with this bacterial continuity. They introduced cell fusion and ploidy cycles into cell life histories. Cavalier-Smith argues that both bouts of mechanical evolution were motivated by similar selective forces: the need for accurate DNA replication without loss of viability.


title: McDonald v. City of Chicago

text: McDonald v. City of Chicago, 561 U.S. 742 (2010), was a landmark decision of the Supreme Court of the United States that found that the right of an individual to "keep and bear arms", as protected under the Second Amendment, is incorporated by the Due Process Clause of the Fourteenth Amendment and is thereby enforceable against the states. The decision cleared up the uncertainty left in the wake of "District of Columbia v. Heller" (2008) as to the scope of gun rights in regard to the states.


title: McDonald v. City of Chicago

text: Initially, the Court of Appeals for the Seventh Circuit had upheld a Chicago ordinance banning the possession of handguns as well as other gun regulations affecting rifles and shotguns, citing "United States v. Cruikshank" (1876), "Presser v. Illinois" (1886), and "Miller v. Texas" (1894). The petition for certiorari was filed by Alan Gura, the attorney who had successfully argued "Heller", and Chicago-area attorney David G. Sigale. The Second Amendment Foundation and the Illinois State Rifle Association sponsored the litigation on behalf of several Chicago residents, including retiree Otis McDonald.


title: McDonald v. City of Chicago

text: The oral arguments took place on March 2, 2010. On June 28, 2010, the Supreme Court, in a 5–4 decision, reversed the Seventh Circuit's decision, holding that the Second Amendment was incorporated under the Fourteenth Amendment, thus protecting those rights from infringement by state and local governments. It then remanded the case back to the Seventh Circuit to resolve conflicts between certain Chicago gun restrictions and the Second Amendment.


title: McDonald v. City of Chicago

text: In "McDonald v. City of Chicago", Chicago resident Otis McDonald, a 76-year-old retired maintenance engineer, had lived in the Morgan Park neighborhood since buying a house there in 1971. McDonald described the decline of his neighborhood and claimed it was being taken over by gangs and drug dealers. His lawn was regularly littered with refuse, and his home and garage had been broken into a combined five times, the most recent robbery being committed by a man whom McDonald recognized from his own neighborhood. As an experienced hunter, McDonald legally owned shotguns but believed them to be too unwieldy in the event of a robbery and so he wanted to purchase a handgun for personal home defense. Chicago's requirement that all firearms in the city be registered but its refusal of all handgun registrations since 1982, when a citywide handgun ban was passed, made him unable to own a handgun legally. As a result, he joined three other Chicago residents in 2008 in filing a lawsuit that became "McDonald v. City of Chicago".


title: McDonald v. City of Chicago

text: Despite being consolidated at the U.S. Court of Appeals for the Seventh Circuit, the cases are different in scope in terms of the specific regulations challenged and the legal argument for applying the Second Amendment against state and local governments. The Second Amendment Foundation brought the McDonald case to the Supreme Court with its lead attorney Alan Gura. The cases were appealed separately to the U.S. Supreme Court.


title: McDonald v. City of Chicago

text: McDonald challenged four broad aspects of Chicago's gun registration law, which, according to the plaintiffs:


title: McDonald v. City of Chicago

text: All of the post-"Heller" cases, including "McDonald", "NRA v. Chicago", "Nordyke" and "Maloney", argued that the Second Amendment, in addition to applying to federal jurisdictions, should also be applied against state and local governments, using a judicial process called selective incorporation. Selective incorporation involves convincing the court that a right is "fundamental" by being "implicit in the concept of ordered liberty" or "deeply rooted in our nation's history and traditions" as defined most recently in the Supreme Court case "Duncan v. Louisiana", .


title: McDonald v. City of Chicago

text: In addition to claiming the Second Amendment should be incorporated through the selective incorporation process, "McDonald" is unique among post-Heller gun cases in that it asked the court to overturn the "Slaughter-House Cases", . "Slaughter-House" determined that the 14th Amendment's Privileges or Immunities Clause did not apply the Bill of Rights to the actions of states (and by extension, local governments). If it had been overturned, the Selective Incorporation process may have become unnecessary, since the entire Bill of Rights, including the 2nd Amendment, would arguably be applied to the states.


title: McDonald v. City of Chicago

text: In attempting to overturn "Slaughter-House", this case garnered the attention and support of both conservative and liberal legal scholars interested in its potential application in areas outside of firearms law. Their interest was that if "Slaughter-House" had been overturned, it would have been possible that constitutional guarantees such as the right to a jury in civil cases, right to a grand jury in felony cases, and other parts of the Bill of Rights, as well as future court rulings and existing federal precedent, not universally guaranteed in actions by the states, would have been applied against the states automatically.


title: McDonald v. City of Chicago

text: In his concurring opinion, Justice Thomas criticized the "Slaughter-House" and "Cruikshank" decisions, proposing that "the right to keep and bear arms is a privilege of American citizenship that applies to the States through the Fourteenth Amendment's Privileges or Immunities Clause."


title: McDonald v. City of Chicago

text: Thirty-three "amici curiae" ("friends of the court") briefs for this case were filed with the Clerk of the Supreme Court.


title: McDonald v. City of Chicago

text: One of these briefs was filed by U.S. senators Kay Bailey Hutchison (R, TX) and Jon Tester (D, MT) and U.S. representatives Mark Souder (R, IN) and Mike Ross (D, AR) asking the Supreme Court to find in favor of the petitioners and rule that the Second Amendment does apply to the states. The brief was signed by 58 senators and 251 representatives, more members of Congress than any "amicus curiae" brief in history. Moreover, thirty-two states under the aegis of Texas (and California independently) also filed "amici curiae".


title: McDonald v. City of Chicago

text: In "People v. Aguilar" (2013), the Illinois Supreme Court summed up the central Second Amendment findings in "McDonald":


title: McDonald v. City of Chicago

text: The majority agreed that the Fourteenth Amendment incorporates the Second Amendment right recognized in "Heller", but was split on the rationale. Writing for four members of the court, Justice Alito found that the Due Process Clause incorporates that right against the States. While joining most of the rest of Alito’s opinion, Justice Thomas, in his concurrence, concluded that the right to bear arms is incorporated only on alternative grounds, namely through the Privileges or Immunities Clause of the Fourteenth Amendment. Alito also reaffirmed, in part of the opinion for four justices, that certain firearms restrictions mentioned in "District of Columbia v. Heller" are assumed permissible and not directly dealt with in this case.


title: McDonald v. City of Chicago

text: Such restrictions include those to "prohibit ... the possession of firearms by felons or mentally ill" and "laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, or laws imposing conditions and qualifications on the commercial sale of arms."


title: McDonald v. City of Chicago

text: Justice Stevens wrote a lengthy dissenting opinion. Among his disagreements with the majority was the statement that incorporation was not at issue in this case. Citing "Cruikshank", Stevens wrote, "The so-called incorporation question was squarely and, in my view, correctly resolved in the late 19th century." In addition, he argued against incorporation, taking issue with the methodology of the majority opinions.


title: McDonald v. City of Chicago

text: Justice Breyer wrote, "In sum, the Framers did not write the Second Amendment in order to protect a private right of armed self defense. There has been, and is, no consensus that the right is, or was, 'fundamental.


title: McDonald v. City of Chicago

text: The initial reactions to the Court's ruling were favorable from both the National Rifle Association and the Brady Campaign to Prevent Gun Violence. Both issued statements to the public that they feel they were vindicated by the Court's holding. However, the court did not include a "clarification of the standard for review" as requested by the Brady group in their amicus brief. In a discussion on the day of the ruling Wayne LaPierre of the NRA and Paul Helmke of the Brady Center both agreed that the Court's ruling ruled out bans on handguns which are to be used for "lawful purposes" such as self-protection in the home. But as to the general question of gun laws not covered in "McDonald", a large number of lawsuits are needed in order to determine whether any other existing State gun regulations might also be unconstitutional. McDonald, supra., stated that the "2nd Amendment is 'fully applicable' to all of the States", but Wayne LaPierre expressed caution that the NRA has "a lot of work ahead" attempting to overturn other gun control regulations not covered by "McDonald". Helmke predicted that in that regard the NRA was "going to lose most of those lawsuits".


title: McDonald v. City of Chicago

text: The day after "Heller" was filed, the National Rifle Association filed five similar lawsuits challenging local gun bans:


title: Pepsiman (video game)

text: The game was made on a low budget, prompting the decision to make videos in-between stages that show a man drinking Pepsi, as they were cheap to produce. The game also features 3D cutscenes, for which the future visual novel writer Kotaro Uchikoshi created 3D models. While an American publisher did look into acquiring the rights to publish the game in the United States, it remained a Japan-exclusive game.


title: Pepsiman (video game)

text: Reviewers frequently compared "Pepsiman" to other games, including "Crash Bandicoot", and commented on its simplicity and its price, which was thought to be low. A writer for "Complex" included it on a list of company-branded games that "didn't suck", commenting that it is not a bad game as long as the player can tolerate the large amount of advertisement in it. According to Uchikoshi, the game did not sell well.


title: Pepsiman (video game)

text: "Pepsiman" is an action game that consists of four stages, each divided into smaller segments, and each involving the superhero Pepsiman saving a person who is dehydrated, such as a military man in the middle of a desert, by giving him a can of Pepsi. The first three stages are based on real locations, San Francisco, New York City and Texas. The last one takes place in Pepsi City. The game is played from a third-person perspective, with Pepsiman automatically running forward through the stages, sometimes running through homes and other buildings. The player takes control of Pepsiman himself, aiming to dodge obstacles, such as cars, construction cranes, and people, as well as Pepsi-branded obstacles, including a Pepsi truck. The player does this by using four different moves: running, dashing, jumping, and super-jumping. The player gains points by collecting Pepsi cans.


title: Pepsiman (video game)

text: In some stages, Pepsiman's head becomes stuck inside a steel drum, which inverts the controls, and in some, he rides on a skateboard, which requires to player to avoid all obstacles. Throughout each stage is a number of checkpoints; if Pepsiman gets hit by obstacles too many times, the player is required to restart from the latest checkpoint. Each stage ends with Pepsiman being chased by an object, such as a giant Pepsi can. In between stages, the player is shown videos of an American man (played by Mike Butters) drinking Pepsi and eating chips and pizza as he watches Pepsiman.


title: Pepsiman (video game)

text: "Pepsiman" is based on Pepsi's mascot of the same name, which was created for Pepsi's Japanese branch. The character, whose fictional backstory says he used to be a scientist who transformed into a superhero after coming into contact with "Holy Pepsi", was featured in Japanese Pepsi commercials and in the Japanese version of the video game "Fighting Vipers"; he became popular in Japan, spawning related characters such as Lemon Pepsiman and Pepsiwoman, and Pepsi decided to promote the character with a video game.


title: Pepsiman (video game)

text: The game was developed by the Japanese video game developer KID. It was made on a low budget, which led to the decision to make the low-cost video scenes of actor Mike Butters drinking Pepsi. The game also uses 3D event scenes, which were modeled by Kotaro Uchikoshi, who would later be a scenario writer for visual novels at KID. This was Uchikoshi's first job; he had been hired to plan video game adaptations of board games, but ended up being part of the development of "Pepsiman" instead, which was already in progress when he joined KID in 1998. The game was released in Japan by KID for the PlayStation on March 4, 1999; while an American publisher was looking into acquiring the rights to publish the game in the United States, it remained Japan-exclusive. Despite this, the game is entirely in English, not Japanese (although with Japanese subtitles for dialogue). According to Uchikoshi, the game did not sell well.


title: Pepsiman (video game)

text: In 2019, the game was featured in an episode of James Rolfe's comedy web series "Angry Video Game Nerd", in which Butters reprised his role from the game's cutscenes. The soundtrack for the game received a vinyl release in 2020 by the European label Chipped Records.


title: Pepsiman (video game)

text: Writers for "Famitsu" called the game "super-simple", comparing it to "Metro-Cross" and "Paperboy", and calling it a simplified version of "Crash Bandicoot". Others have made similar comments. A reviewer for IGN also compared it to "Crash Bandicoot", described the gameplay as "simplistic [and] route memorization-based", and said that the thing the game would be remembered for was its "extremely bizarre premise". They still felt that the game was not bad, and that it was worth the price, which they noted was low. James Mielke at GameSpot called the game a "nifty little distraction", and said that the gameplay was similar to the "old-school gaming dynamics of yesteryear". He commented on the low price, but said that it was difficult to find imports of it. "Gamers' Republic" magazine rated the game a B−. "Gamers' Republic" later listed "the game" in their "1999" "Video Game Buyers Guide and Y2K Preview" as one of the best games to import from Japan that year.


title: Pepsiman (video game)

text: In 2011, Allistair Pinsof at Destructoid reviewed the game, calling it a mix between "Paperboy" and "Muscle March" in terms of the complexity and pace, and compared the gameplay to "Crash Bandicoot". He found it to be "such a gloriously twisted, charming spectacle" that it would be difficult not to like it; he said that the main reason to play the game is "the sheer lunacy" of it, saying that the game is "obsessed" with America, and portrays Americans as "unhygienic hillbillies" in a manner that makes it unclear if it is a self-aware parody or not. He concluded that the game is funny, but not great, and that the ridiculous premise and its large amount of small details make the game "charmingly brain-dead". In 2013, Justin Amirkhani at "Complex" included the game in a list of company-branded video games that "didn't suck", saying that while the game's graphics had not aged well, it was mechanically very similar to "Temple Run", which Amirkhani called his favorite iOS game. He concluded that "Pepsiman" is not a bad game for people with quick reflexes, as long as they can stand the high amount of advertising within the game; he claimed that "Pepsiman" was the advergame with the largest amount of "logos-per-second".


title: Pepsiman (video game)

text: In 2015, "Retro Gamer" magazine listed it as number 18 on their list of "The 20 Greatest PlayStation Games You've Never Played".


title: Blew

text: "Blew" is a song by American rock band Nirvana, written by vocalist and guitarist Kurt Cobain. It is the first song on the band's debut album "Bleach", released in June 1989 by Sub Pop.


title: Blew

text: The song was re-released by the Tupelo record label as the title track of a four-song Nirvana EP in the United Kingdom in November 1989, where it charted at number 15 on the UK Indie Singles chart.


title: Blew

text: Written in 1988, "Blew" was first performed live at the Community World Theatre in Tacoma, Washington on March 19, 1988.


title: Blew

text: The song was first recorded in the studio by Jack Endino at Reciprocal Recording Studios in Seattle, Washington in June 1988, during the recording sessions for what became the band's debut single, "Love Buzz".


title: Blew

text: A second studio version was recorded by Endino at Reciprocal in December 1988, and was released on "Bleach" in June 1989.


title: Blew

text: The "Bleach" version of "Blew" was accidentally recorded one step lower than the band had intended, which contributed to what Nirvana biographer Michael Azerrad called its "extraordinarily heavy sound". Not realizing that they had already tuned to their favored D Standard tuning, the band tuned further down to Drop C on the first day of the sessions and recorded several songs in that tuning. As bassist Krist Novoselic recalled in a 2009 "Seattle Times" article, "we came back the next day and decided the idea wasn't so hot, and we recorded over most of it with things tuned back up a little. In fact, 'Blew,' with that growly bass, is the only survivor of that experiment."


title: Blew

text: The "Bleach" version of "Blew" was re-released on the "Blew" EP in December 1989, along with the "Bleach" mix of "Love Buzz" and the previously-unreleased songs "Been a Son" and "Stain", which had been recorded by Steve Fisk at Music Source in Seattle, Washington in August 1989. The band's original plan had been to release an EP to promote their current European tour, but the EP was delayed and released exclusively in the United Kingdom after the tour was over. However, the EP built on the interest the band had generated in the UK with "Bleach", and was promoted by English DJ John Peel, who had also played "Bleach" on his influential show. The "Blew" EP eventually peaked at number 15 on the UK Indie chart.


title: Blew

text: "Blew" remained one of only three songs from "Bleach", along with "About a Girl" and "School," that the band performed until Cobain's suicide in April 1994. It was performed for the final time live at Nirvana's last show, at Terminal Einz in Munich, Germany on March 1, 1994, as the second-to-last song, preceding "Heart-Shaped Box".


title: Blew

text: In his 1993 Nirvana biography "", Azerrad described the song as having a "theme of entrapment and control."


title: Blew

text: In 2009, Novoselic said that "Blew" was perhaps his favorite song on "Bleach" "because it has a groove, and again, it's the sole survivor of the Doom Pop experiment."


title: Blew

text: The "Blew" EP was released in December 1989 on Tupelo Records on 12" vinyl and CD. With a working title of "Winnebago"., the EP was originally intended to be released to promote an upcoming European tour, but due to delays in production, the maxi-single ended up being released exclusively in the United Kingdom shortly after the tour's completion.


title: Blew

text: The "Blew" EP was released only in the UK and was difficult to obtain elsewhere. Only 3,000 copies of the maxi-single were pressed on 12" vinyl and CD. Both vinyl and CD counterfeit copies exist, with the vinyl copies varying in color. The official 12" vinyl was pressed only on black vinyl. The cover art was photographed by Cobain's then-girlfriend Tracy Marander at a May 26, 1989 concert at the Green River Community College in Auburn, Washington. The back cover photo was also by Marander.


title: Blew

text: "Stain" was re-released by DGC Records in December 1992, on the band's rarities compilation, "Incesticide". The "Blew" version of "Been a Son", hailed by Kurt St. Thomas as the "definitive take" due to its trashy sound and pronounced bass solo, remained a rarity until it was re-released in October 2002 on the band's first best-of compilation, "Nirvana".


title: Ayia Napa

text: Ayia Napa ( , ), officially romanised Agia Napa, is a tourist resort at the far eastern end of the southern coast of Cyprus.


title: Ayia Napa

text: The name Ayia Napa is derived from a Venetian-era monastery of the same name, located in the centre of the town, next to the square that today is the clubbing centre. The word "Ayia" means "holy" in Greek. "Napa" is archaic and means "wooded valley" or "dell". In ancient times the area surrounding the town was covered with thick forest.


title: Ayia Napa

text: Ayia Napa lies near Cape Greco at the eastern part of Cyprus, south of Famagusta, and forms part of a larger area known as "Kokkinochoria" ("Red Villages", a name derived from the vivid red colour of the soil). It is a town of the Famagusta District, in the remaining Greek-controlled southern part of the district, while the northern part has been occupied by Turkish forces since 1974. Ayia Napa is about from Protaras, which has also been developed as a tourist destination.


title: Ayia Napa

text: According to a local legend, a hunter in pursuit of his prey discovered an icon of the Virgin Mary in a cave, after which a monastery dedicated to her was built around the cave; the name Virgin Mary of Napa was eventually shortened to Ayia Napa. Another legend has it that a Venetian noblewoman fled from her parents, who forbade her from marrying a commoner, to live there as a nun. The Venetians built a church in  1500. According to local tradition, the area (except for the monastery) was uninhabited until about 1790, when Nikolaos Kemitzis of Thessaloniki arrived from Greece and settled in the village of Panayia, located in the northeastern part of Ayia Napa. Kemitzis had come into conflict with the Ottoman authorities who then ruled Cyprus, and decided to move near the monastery of Ayia Napa.


title: Ayia Napa

text: Between 1999 and 2003, Aiya Napa was the UK garage music summer holiday destination, attracting DJ Spoony, MC Creed, MC DT, Norris "Da Boss" Windross, Kele Le Roc, MC CKP, "Little Charlie", and "So Solid Crew".<ref name="i-D/ukg-documentary-garage"></ref><ref name="theneweuropean/village-to-heart-of-garage"></ref>


title: Ayia Napa

text: In 2014, Ayia Napa was given the status of a main city-urban centre by the Government of Cyprus, in recognition of its importance to the economy. This was credited to the efforts of Mayor Yiannis Karousos, elected in March 2013. The city of Ayia Napa has the seventh largest budget of the 30 active municipalities of Cyprus, and employs 280 people.


title: Ayia Napa

text: The City of Ayia Napa is governed by a mayor, an alderman, and a six-member city council; Christos Zannetou was elected mayor in January 2020. It is well known for its municipal management, which has influenced that of other local authorities in Cyprus.


title: Ayia Napa

text: Until the end of 2014, beaches in Cyprus were under the management of private individuals and companies which were given licences to manage the beaches directly and without public tenders. Mayor Yiannis Karousos led an initiative to place all the city's beaches under direct city management. Ηe and the councillors who voted for the proposal faced threats and legal actions, but the city received over 3.5 million euros in annual revenue from beaches, and all beaches in Cyprus are now managed by the local authorities.


title: Ayia Napa

text: In October 2017, the city decided that €240,000 of its development budget will be allocated to projects proposed and chosen by citizens and organisations of Ayia Napa, becoming the first city in Cyprus to implement a participatory budget.


title: Ayia Napa

text: In January 2017, Ayia Napa become the first city council in Cyprus to transmit a live webcast of its council meetings.


title: Ayia Napa

text: Starting in 2017, the city instituted an annual survey of citizens, businesses, and visitors evaluating the city and giving feedback.


title: Ayia Napa

text: Through an online app, citizens and visitors can report issues and make complaints and track how long it takes the city to fix the problem.


title: Ayia Napa

text: On 2 May 2018, the city signed an agreement with the University of Nicosia under which the university will act as consultant to the city in implementing blockchain technology, artificial intelligence, and smart city utilities; it is the first city in Cyprus to implement blockchain technology.


title: Ayia Napa

text: Ayia Napa is the largest tourist resort in Cyprus, with a 27,000-person-bed capacity and more than 175 hotels and apartments of all sizes. In 2017, the resort received over 700,000 tourists and accommodated 5 million overnight stays, representing approximately 30% of all Cyprus overnight stays.


title: Ayia Napa

text: Beginning in the 2010s, under Mayor Yiannis Karousos, the city has sought to expand tourist offerings and declared an aim of discouraging rowdy groups of young tourists and becoming "the best and most cosmopolitan tourist resort of the Mediterranean" by 2030. Since 2013, it has shut down problematic establishments, upgraded infrastructure, hotels, and restaurants, and added facilities such as a new marina and the underwater museum. The vision set by the city is supported by the Cyprus Tourism Strategy, which was completed in March 2017 and aims for Ayia Napa to be "regarded as one of Europe's top three beach and nightclubbing holiday destinations [...] offering the best beach and marine experience in Cyprus for young adults, complemented by international standard beach clubs and nightlife". The strategy evaluated the then quality of Ayia Napa as 3.4/5 and proposed that it should plan to increase its quality to 4.4/5.


title: Ayia Napa

text: Ayia Napa was recognised as a "Prime City Destination" by the Oxford Business Assembly, and in 2018 was awarded the International flag of investment and innovation attractiveness 'Flag of Europe" and the International Certificate of Excellence in Investment and Innovation (ICEII).


title: Ayia Napa

text: The resort has 27 beaches, of which 14 have been awarded the Blue Flag award, more than any other resort in Cyprus; the island itself also has the second highest amount of Blue Flags in the world, behind only Croatia. In 2011, Nissi Beach topped the TripAdvisor list of the best beaches in Europe. In 2017, Makronissos Beach was chosen by "Travel Weekly" as the third best beach for Cyprus and Greece. In 2018, it was announced that Nissi Beach ranked third in the list of the most popular beaches on Instagram. A CNN feature ranked Nissi Beach as the best beach to visit for the month of July 2018.


title: Ayia Napa

text: The foundation stone for Ayia Napa Marina was laid on 30 September 2016. It was the largest private project in Cyprus at the time and is expected to cost €250 million and be completed in 2021. The main investor is Egyptian billionaire Naguib Sawiris, who was presented with a golden key to the city by Mayor Yiannis Karousos at the foundation ceremony.


title: Ayia Napa

text: Ayia Napa medieval monastery is the main point of significant historical interest in the Ayia Napa area. The oldest parts of the existing monastery are some wall sections from the Middle Byzantine era (before 1191); most of the buildings are from the 14th–18th centuries. It now houses a museum.


title: Ayia Napa

text: The Makronissos Tombs are an archaeological site consisting of set of ancient rock-cut tombs, an adjacent sanctuary and quarry, and evidence of funeral pyres.


title: Ayia Napa

text: The town contains two municipal marine museums: the Tornaritis-Pierides Museum of Marine Life and the Thalassa Agia Napa Municipal Museum (also known as the Thalassa Museum of the Sea). The former, founded in 1992, displays marine fossils, specimens, and dioramas. The latter, founded in 2005, displays the "marine heritage of Cyprus, from prehistoric times to the present" and features a full-scale replica of a  300 BCE merchant ship which was salvaged during the 1960s.


title: Ayia Napa

text: The Ayia Napa Sculpture Park, on the east side of the city, was inaugurated in May 2014 with 17 sculptures. By January 2018 it included more than 200 sculptures by 140 sculptors from all over the world. The sculpture park was accepted as a member to the International Sculpture Symposium Alliance, and has been turned into an international attraction, with the participation of artists from all over the world.


title: Ayia Napa

text: The Museum of Underwater Sculptures Ayia Napa, with 93 works by British sculptor Jason deCaires Taylor off Pernera Beach, opened in 2021. Sculptures are at a depth of , accessible to both snorkellers and scuba divers. It is the first of its kind in the Mediterranean. (link below)


title: Ayia Napa

text: "The Fisherman of Ayia Napa", inaugurated in June 2015, is dedicated to the fishermen of the world. The population of Ayia Napa once consisted of mainly fishermen and farmers.


title: Ayia Napa

text: "The Mermaid of Ayia Napa", a sculpture at the harbour inaugurated in 2015, was inspired by the poetry of George Seferis and by the legendary sister of Alexander the Great. She has two tails.


title: Ayia Napa

text: "The Farmer of Ayia Napa", inaugurated in July 2016 in a square created on Yiannaki Pappoulis Street as part of the initiatives to improve the city centre.


title: Ayia Napa

text: "Kemitzides, the Family of Ayia Napa", a group of three statues donated to the city by five local families and inaugurated in September 2016: a man in Greek dress, a classic Cypriot woman, and a child, commemorating the founding family of the city and symbolising their continuation.


title: Ayia Napa

text: "From Yorgopotamos to El Alamein", dedicated to the citizens of Ayia Napa who participated in the First and Second World Wars and inaugurated in October 2016 in the presence of the Minister of Defence.


title: Ayia Napa

text: The Ayia Napa International Festival, first held in September 1985, is held annually in Sepheris Square in Ayia Napa Monastery, usually over the last weekend of September. The festivities reflect the historic, cultural and agricultural traditions of Ayia Napa and Cyprus as a whole. The programme includes theater performances, operas, concerts, and Cypriot and foreign folk dancing. Visitors can also enjoy art and photo exhibitions, wood carving and silversmithing workshops, and culinary shows with halloumi cheese making.


title: Ayia Napa

text: The Ayia Napa Youth Festival was established in 2010 when the Ayia Napa Youth Council accepted the proposal of its president Yiannis Karousos and decided to organise a festival similar to the large music festivals of Europe. The festival is based on several principles such as free entrance, the headliners to be chosen by the public, a charity goal, and a social responsibility message. All styles of music are welcome. The first festival took place at the harbour square and received more than 10,000 visitors over three days; bands included the Greek reggae act Locomondo, pop-rock band MPLE, and hip hop band Stavento featuring Ivi Adamou. In 2011, the festival became international and included Stratovarius, Sabaton, Rotting Christ, Nightstalker, and other bands from all over Europe. The 3rd Ayia Napa Youth Festival took place in 2012.