Evolutionary theory on the move : New perspectives on evolution in the cognitive science of religion

This article discusses the use of evolutionary theory in the cognitive science of religion (CSR), with special attention to critical issues and new developments. In the first part of the article, I will discuss the definition of evolution and describe the Modern Synthesis (or neo-Darwinian theory). In the next part, I will consider various evolutionary perspectives in CSR, including evolutionary psychology, sexual selection, gene-culture co-evolution, and cultural evolution. In the final part, I will turn to the problems with the Modern Synthesis and present a new approach based on network theory, with potential applications to the study of biological and cultural systems.

Evolutionary theory is on the move.Until about fifteen years ago, at least most biologists would have agreed on the main lines of what evolution was and how it worked.Apart from some controversial ideas (such as group selection, on which more below), the so-ca led neo-Darwinian synthesis (or Modern Synthesis) went mostly uncha lenged.This is har ly the case any longer, with some of the basic tenets of the mid-twentieth century consensus being ca led into question.The purpose of this article is to discuss some of the recent developments in evolutionary theory with ecial attention to their (potential) ap lications in the study of religion.We wi l start by outlining some more traditional views and proceed toward innovative ap roaches.
Charles Darwin summarized the concept of evolution as "descent with modification over time" (Darwin, 1909, p. 132, 178, 380, etc).For a more extended formulation of the same basic idea, we can turn to a recent textbook definition (Moran, 2006, p. 1): "Evolution is a process that results in herita le changes in a population spread over many generations." It is important to recognize how broad the basic (Darwinian) definition of evolution is.Notwithstanding simplistic, popular understandings of evolution, such as the "survival of the fittest" (an expression coined by Herbert Spencer), evolution as defined above can take place by several mechanisms, such as drift, migration, mutation, and natural selection.Ar ua ly, the most interesting and certainly the most intensely studied form of evolution is natural selection, which occurs when the frequency of a herita le trait that improves reproductive success increases in the population with time (Stearns and Hoekstra, 2005, p. 2).
Another nota le a ect of the Darwinian notion is that it does not include genes.In fact, none of the definitions we have considered so far mentioned genes at a l.If we now turn to the Modern Synthesis, which is what evolution rea ly means for most biologists, genes become of central importance.It is not easy to give a straightforward definition of evolution in neo-Darwinian terms: one could say that the classical Darwinian concept was simple and elegant, while allowing for diverse ap lications, whereas the neo-Darwinian concept is more ecific, yet cumbersome to define.Instead of a single definition, it is easier to think about neo-Darwinian evolution in terms of four different processes (Walsh and Huneman, 2017, p.As it ap ears, a l four components of the Modern Synthesis have come under attack recently.Before looking at some of the su ge ed modifications and extensions, let us consider how classical evolutionary theorizing has influenced the cognitive science of religion (CSR).

Evolutionary psychology and the beginnings of the cognitive science of religion
Evolutionary psychology studies cognitive and behavioral adaptations to evolutionary pressures.More ecifica ly, evolutionary psychologists focus on the evolved mental architecture of Homo sapiens that has been shaped by more or less consistent environmental conditions for tens of thousands of years, before humans started to live in large societies and invented agriculture.These conditions (associated with life on the African savannahs in the Pleistocene period, dated between 2.5 mi lion and 12,000 years ago) provided evolutionary pressures that shaped the human mind in fairly consistent ways before Homo sapiens started to migrate out of Africa (traditiona ly dated to around 100,000 years ago, but potentia ly pushed back in time by recent archeological finds).Some of the implications of evolutionary psychology include the hypothesis of ecialized systems of the mind that deal efficiently with salient pro lems, such as predation, mating, contagion, and various a ects of social life.
The theory of the modularity of mind has been e ecially influential in CSR.The astounding versatility and efficiency of the human mind begs explanation.Jer y Fodor (1983) su ge ed that the mind includes a number of modules that deal with different kinds of information.The modules are loosely related to the senses and are domain-ecific, that is, they deal with some a ect of the world and process only information that is relevant to that a ect.Leda Cosmides and John Tooby (Cosmides andTooby 1987, 1994;Tooby and Cosmides, 2000), together with a number of other scholars, reasoned that evolution created ecialized cognitive systems in the human mind that coped with ecific cognitive tasks in the environment of our ance ors.This version of modularity is ca led mas i e mo ula ity, or the "Swiss army knife" model of the brain.While ecialized cognitive modules are useful for dealing with ecific tasks efficiently, they make it very difficult to learn, innovate, or develop a unified sense of self and consciousness that humans have.Steven Mithen (1996) addressed this pro lem by su gesting a three-phase evolution of the mind: a general-inte ligence mind capa le of learning and decision-making; a mind of ecialized inte ligences (a simpler version of the Swiss army knife model) that deals with different domains efficiently; and a mind with flow of knowledge and ideas (cognitive fluidity) between domains.
The massive modularity hypothesis provided a major impetus for emerging CSR in the 1990s.Evolved mental systems, it was emphasized, constrain human culture, which can only take forms that are ena led by the existing mental structures.As a result, even though cultural forms are very diverse, this diversity is neither random nor limitless.For example, lan uages, despite their great diversity, use a limited variety of sounds and phonetic combinations that our minds, eech organs, and senses can produce and process.As CSR emerged in the 1990s, evolutionary psychology played a particularly important role in the work of Stewart Guthrie (1980Guthrie ( , 1993)), Pascal Boyer (Boyer 1994(Boyer , 2001(Boyer , 2018;;Boyer and Liénard, 2006), and I kka Pyysiäinen (2003Pyysiäinen ( , 2004Pyysiäinen ( , 2009)), while it also influenced the ritual form theory developed by E. Thomas Lawson and Robert N. McCauley (Lawson and McCauley, 1990;McCauley and Lawson, 2002), and other contributions.
The use of evolutionary psychology in the study of religion can be criticized on several accounts.First, explanations with recourse to evolutionary psychology often give the impression of being just-so stories, ones that make sense but are hard to prove.Second, cognitive mechanisms can be studied with the help of experimental and other methods and one may question whether the evolutionary explanation attached to a given mechanism rea ly a ds anything relevant to it.Third, the timeframe that is usua ly considered when reasoning about human cognitive universals can be pro lematic.Human migration (or multiple migrations) out of Africa might have taken place in several waves and possi ly much earlier than it was assumed previously (Stringer, 2016).As a consequence, various human populations could have ent sufficiently long time in different environments and interbred with other hominids for theorizing about life on the African savannah being of limited value for understanding human cognition.
One might ar ue, however, that evolutionary psychology (when relying on sufficiently robust evidence, such as insights from primate studies or paleoanthropology) enhances cognitive scientific explanations by showing the deep relationships between empirica ly observed cognitive mechanisms and the connection between cognitive mechanisms and re ective environmental cha lenges.Instead of dismissing evolutionary psychology as an ap roach to religion, we can make use of recent developments and more refined theories in the field.For example, the work of Merlin Donald (1991) and Robert Be lah (2011) considered different timescales and a dressed more varied effects of evolution on cognition and religion than the studies before them (although their eculative nature has come under criticism [see, e.g., Horst, 2012]).More recently, the fields of cognitive archeology and paleoneurology emerged to combine insights from cognitive neuroscience, evolutionary theory, and archeology in the understanding of human cognitive evolution (e.g., Coolidge et al., 2015;Hai le et al., 2016).

Sexual selection
The study of sexual selection is one of the classical branches of evolutionary science.While sexual selection it-self is as complicated and multi-faceted as the rest of evolutionary theory, the basic idea can be summarized as fo lows: a trait variant that helps the organism to produce more offspring with partners of better quality (see below) wi l spread as long as its possi le negative effects on other a ects of reproductive success (such as preventing the organism from reaching reproductive age or raising the offspring) do not outweigh its advantages.
During the past decade, scholars su ge ed several ways in which the emergence of religion in Homo sapiens could be explained in the framework of sexual selection.Most of the relevant work focused on mate choice, essentia ly hypothesizing that religious displays make potential mating partners (in most theories, males) more attra ive.For example, Jason Slone (2008) proposed that religion evolved, at least in part, to sup ort the assessment of the qualities of potential mates.Pyysiäinen (2009, p. 207-208) su ge ed that ritual dance can be a good indicator of male fitness and thus function as a male ornament in sexual selection.Rüdiger Vaas and Michael Blume (2009, p. 136-137) identified various elements of religion, in which typica ly males engage themselves, as potential hard-to-fake signals of fitness, such as tortures of the body, time-consuming rituals, postures that prevent other a ions, life-long scriptural studies, meditations, prayers, renouncing consume or nourishment, and high costs of temples, costumes, and art.
Other su gestions about the role of sexual selection in the origins of religion dealt with long-term bonding and joint parenting.Some ethnographic and experimental data suggests that religious beliefs and behavior sup ort long-term, monogamous relationships at least in some contemporary societies (Bu bulia et al., 2015;McCu lough and Wi loughby, 2009;Watts et al., 2015a;Weeden, 2015;Weeden et al., 2008).
More recently, work on religion and sexual selection developed in yet another direction, looking into the connection between religion and mate uarding.For example, Sela et al. (2015) made a case for the use of religion as a tool of a gression in sexual selection.They noted that both intrasexual a gression between men and various forms of intersexual a gression by men toward women provide males with a reproductive advantage.Pazhoohi et al. (2017) su ge ed that religious veiling is a mate-uarding strategy and showed that the pra ice becomes more frequent in harsher environments.Fina ly, Czachesz (2018a) proposed that proto-religious traits emerged in Homo erectus in the context of mate-uarding, more ecifica ly, as an adaptation in males uarding a group of female mating partners.
Given that sexual selection can produce very strong effects, it is almost beyond dispute that it influenced the development of religion in one way or another.It is surprising that the discussion about religion and sexual selection has remained rather marginal in CSR so far.Recent studies explored various a ects of the pro lem and opened up the discussion in several directions simultaneously.It is quite reasona le to sup ose that religion and sexual selection intera ed in different ways during human evolutionary history.Learning from recent developments in cognitive paleoanthropology (see above) and paying attention to ecific pro lems at different stages of human and hominid cognitive evolution could lead to improved theorizing in this exciting area (see Czachesz, 2018a).

Gene-culture co-evolution
Gene-culture co-evolution offers a new way of looking at the connection between evolution and culture, beyond the important but limited insight that the evolved mind constrains cultural forms.Cultural pra ices, if they exist persistently over a sufficiently long period of time, wi l constitute evolutionary pressures, just as other environmental factors do.We l-documented genetic adaptations to culture include the shape of the human larynx (assume ly an adaptation to lan uage) and the ability to digest mi k in adults (at least in many populations) (Ja lonka and Lamb, 2005, p. 286-317).On a general level, human lan uage (and material culture) has shaped the mind as much as humans shaped their environments.According to the theory of cogniti e ratc eting, proposed by Michael Tomase lo (Tomase lo, 1999;Tomase lo et al., 1993), sma l changes in the mind led to sma l changes in the artifacts made by early humans, which, in turn, initiated further changes in the mind.It is possi le, however, that the nota le cases of genetic adaption to cultural pressures (such as lan uage and dairy farming) constitute rather than the rule: it has been ar ued (Gi bons, 2010) that the spread of beneficial mutations usua ly takes longer than the relatively short history of dairy farming would have a lowed for.In ecial circumstances, however, genetic mutations can spread faster than norma ly.Artificial selection and self-domestication provide such examples in animals and plants.
The theory of gene-culture co-evolution can be taken into consideration in different ways in the study of religion.First, it is beyond dispute that religion has been with Homo sapiens and its ance ors for sufficiently long time so that religious beliefs and behaviors could shape human biological traits.It is reasona le to hypothesize that some form of religion, such as ritual displays, and some form of belief in ance ors and spirits preceded the ap earance of lan uage and symbolic thought in evolutionary history.For example, if certain expressions of religion (such as artistic and ritual displays) increased reproductive fitness (as we think better lin uistic expression did), the necessary cognitive and sensory-motor ski ls would have been selected for.Let us note that in this hypothetical scenario we are considering religion as a continuous environmental condition.The su ge ed process is different from the assumed selection of religious traits that are thought to enhance cooperation and group solidarity, for example.Admitte ly, such ar uments remain difficult to prove, which takes us back to our discussion of the potential of evolutionary psychology above.
Second, one can study the effect of religion on particular historical populations, in the same way as we can study lactose tolerance or sickle-ce l anemia.For example, Gabriel Levy (2012) considered the effects of literacy, endogamy, social isolation, and other factors on biological traits in Jewish history.More genera ly, one can ar ue that religion plays a significant role in shaping and maintaining social boundaries, dietary habits, marital structures, and other cultural patterns, and can be expected to cause relatively rapid evolutionary change e ecia ly in the genomes of isolated populations.

Cultural evolution and group selection
The theory of cultural evolution ap lies the principles of evolutionary theory to the study of transmission processes and long-term developments in culture.It is obvious that humans pass on not only genes but also cultural items (such as ideas, stories, and artifacts) to their offspring.According to Richard Dawkins (2006Dawkins ( [1976]]), culture is passed on in the form of me es, which are units of culture that can be inherited independently of each other.Examples of memes are "tunes, ideas, catch-phrases, clothes fashions, ways of making pots or of building arches" (Dawkins, 2006, p. 192).If culture is inherited in gene-like units, it is reasona le to ask whether natural selection and other evolutionary dynamics ap ly to it.
The concept of the meme has been criticized on different accounts (Kundt, 2015).First, it is not straightforward to isolate memes from other memes: for example, is Bu dhism a meme?Second, what is the building material of a meme?Third, the mechanisms of copying memes are not we l known: ecifica ly, it seems that they are copied with less fidelity than genes.A dressing the latter pro lem, Dan Sperber (1996Sperber ( , 2000) ) ar ued that pieces of culture are not copied with high enough fidelity so that something like natural selection could act on them; the stability of cultural traits is due to psychological biases rather than to the faithfulness of copying.According to Sperber, among the range of possi le forms a cultural bit can take there are optimal forms dictated by psychological factors, which he ca ls attracto positions.For example, people wi l copy the idea of a ghost with low fidelity (missing or distorting details and a ding new ones), but the idea wi l remain relatively sta le across generations because the idea of a ghost is constrained by innate psychological structures (cf.Boyer, 2001;Pyysiäinen, 2009).It has been su ge ed (Czachesz, 2017a, p. 42-48;McElreath and Henrich, 2007) that although Sperberian attra ion influences culture, it does not exclude the existence of other processes of transmission, such as natural selection.In other words, psychological biases provide constraints that limit the range of possi le forms of culture that can survive in the long run; however, there are sti l possibilities for variation and selection within those limits.For example, although concepts of ghosts are fundamenta ly shaped by evolved, cross-cultura ly consistent psychological mechanisms, particular representations of ghosts, tales about ghosts, or prac- tices related to ghosts and spirits can take different forms so that cultural evolutionary processes can shape them.
Another conte ed a ect of cultural selection is the assumed intentionality of cultural innovations, which is contrasted with the randomness of genetic variation, on which natural (biological) selection acts.As Alex Mesoudi (2011, p. 33-34) pointed out, however, cultural innovation is much less intentional than innovators tend to claim.In fact, cultural innovations usua ly result from long chains of trials and errors, often in many generations of thinkers and tinkerers.Yet another contradiction with the neo-Darwinian theory is the passing on of acquired cultural traits.A cor esponding inheritance of acquired biological traits is strictly rejected by the Modern Synthesis.This is related to the pro lem of o lique transmission: while we cannot inherit genes from our peers, we can learn new ideas from them.Discussing the cha lenges to cultural evolutionary theory, Mesoudi (2011, p. 46-47) su ge ed that cultural evolution might not be neo-Darwinian, but sti l Darwin's original concept of evolution can be helpful in studying it.
It is quite possi le that we can identify evolutionary processes in various mediums (for example, computer modeling offers many op ortunities), using the broad definition of (Darwinian) evolution, and discover other rules that ap ly only to one or another type of evolution.Further, as we wi l see in a moment, some of the basic tenets of the Modern Synthesis are being ca led into question and new insights about biological evolution might shed new light on cultural evolution.
While cultural evolution can be examined in the context of individual differences in reproductive success, its ap lications to religion have taken selection on the level of groups as a starting point.The concept of group selection (Nowak and Highfield, 2011, p. 81-94;Wilson andWilson, 2007, 2008) states that some genes contribute traits that are neutral or even disadvantageous for the reproductive success of the individual but are transmitted because they benefit the group.Group selection presup oses the formation of closed social groups: if a group can reproduce much more successfu ly than other groups due to pro-social behavior within the group, the spread of the genes of non-cooperating group-members can be neutralized.The use of group selection in cultural evolutionary theory a lows for a number of other mechanisms (cf.Richerson and Boyd, 2005, p. 197-211).For example, cultural memes can be learned from other groups, a group can physica ly annihilate another group, or group members can migrate to other groups (to the point of complete assimilation).The definition of groups and group membership poses cha lenges for most group-selectionist accounts.People are members of several social groups at the same time and the boundaries of social groups are usua ly fuzzy.In the context of cultural evolution, one could define a group as the co lection of a l individuals who car y a certain meme.This of course implies that the members of such a group wi l not necessarily know each other or interact with each other, which might be a pro lem for some (but not a l) ap lications of group selection.
Cultural group selection has been invoked to explain religion, either as an evolved or exapted trait (that is, an evolved trait that gained a new function).Perhaps the most famous statement has been David S. Wilson's Darwin's Cathedral (2003), which focused on Calvinist Christianity as a test case.As Wilson (2003, p. 54) acknowledged, his ap roach is indebted to Durkheim's functionalism, as indeed are most other ap roaches to religion as an adaptation to solve the pro lem of social cooperation (Bu bulia and Sosis, 2011;Johnson, 2015;Norenzayan, 2013;Teehan, 2010;Turner et al., 2018).It has to be noted that much of the work inspired by Durkheim seems to proceed from the a p io i assertion that religion answers some pro lem of social cooperation.While it is obvious that religion can have a major impact on society, pursuing grandiose hypotheses might not be the most useful strategy from the per ective of advancing cultural evolutionary theory.Contemporary and historical case studies, such as Richard Sosis' work on Israelite ki butzim and utopian communities (Sosis, 2000;Sosis and Bressler, 2003), phylogenetic modeling of cultural traditions (Watts et al., 2015b), or ongoing work on early Christian texts and communities (Czachesz, 2017b;Luomanen, 2017) might be helpful in map ing out the mechanisms and limitations of cultural (group) selection when applied to historical data.

Beyond the Modern Synthesis
While the critics of meme theory have a point in questioning the value of the meme concept to describe units of inheritance, it ap ears that the nature of genes as units of inheritance has become pro lematic, too.In this part of the article, I wi l present some of the major cha lenges to the Modern Synthesis, as we l as some su ge ed changes to evolutionary theory.
The concept of the gene goes back to Georg Mendel and Wi helm Johannsen (the latter introduced the word), who thought about it as something causing an inherita le phenotypic trait.After the discovery of DNA, genes were identified with discrete sequences of nucleotides that encode functional units of proteins.Soon it turned out that a single nucleotide can belong to more than one gene and different parts of the same gene can be used to create different proteins (Fa k, 2010, p. 259-267).Further, humans have considera ly fewer genes (on the order of 30,000) than geneticists expected (on the order of 100,000) even two decades ago.An individual gene seldom codes for one ecific trait.Various new developments in evolutionary science have helped us to understand these surprising outcomes.
First, e igenetics determines how genetic material is activated or dea ivated in different contexts and situations (Moore, 2015, p. 14).As a result, the same genetic information can yield divergent phenotypic traits.Moreover, epigenetic changes in the organism can be passed on to subsequent generations, a phenomenon ca led epigenetic inheritance (Moore, 2015, p. 145-166).Epigenetic inheritance can deter-mine, among others, food preferences and the utilization of nutrients in several generations (Bateson et al., 2004;Menne la et al., 2001;Moore, 2015, p. 125-126;Quarta et al., 2016).Epigenetic inheritance summarizes the experience of multiple generations and raises interesting questions about the biological foundations of religious food traditions and other cultural traits (Czachesz, 2018b).
Further, genes are organized into networks to produce phenotypic traits.So-ca led gene re ulatory networks include DNA, RNA, and proteins, which interact in complex ways to decide what genetic information is transcribed in a given context (Davidson and Peter, 2015).Requiring fewer components to code for more traits is not the only benefit of this arrangement.As it turns out, genetic re ulatory networks have a modular structure (Zhang and Zhang, 2013).It is assumed that the modular structure of the networks makes it less likely that random mutations result in harmful changes and helps to preserve successful evolutionary designs (Wi kins, 2007).
Meanwhile, the field of evolutionary developmental biology (evo-devo) emerged, with the purpose of studying the role of development in evolutionary change (Ha l, 2012).It has been understood that the physical design of the organism takes over a variety of tasks from the genome and the epigenome.For example, many features of the limbs develop as a result of biological and environmental constraints, both ensuring their functionality and making genetic coding for the re ective features unnecessary.As was the case with gene re ulatory networks, the study of developmental templates led to insights about their role beyond the obvious benefit of reducing the size of the genetic code.It has been ar ued (U ler et al., 2018) that evolution acts on a system comprising both the organism (with its physical properties) and the genome (including re ulatory networks and epigenetics).
These and other insights resulted in ca ls for a new evolutionary science beyond the Modern Synthesis (Huneman and Walsh, 2017).For example, U ler et al. (2018) considered the phenotype as a re ulatory system, which a lows for "facilitated variation" (a position between random variation and directed variation) in evolutionary change.Stewart Newman (2017) ar ued for a "nonidealist evolutionary synthesis, " which takes into consideration the ways physics and biological materials influence the evolution of form.Fina ly, Denis No le (2015) ca led for a reconsideration of the distinction between replicator and organism.
What is the significance of these new developments for the study of religion?(1) First, it has to be noted that biologists are divided over the implications of the new insights about evolution for the Modern Synthesis (Laland et al., 2014).However, it is not the fate of the neo-Darwinian consensus that matters most for scholars of religion.The various new (and not so new) insights about how evolution works can be considered independently of their consequences for the future of evolutionary science.(2) Second, the above mentioned developments in evolutionary theory shed new light on how genes and culture interact (Rosa and Müller, 2018).
Meanwhile, growing attention to development, the organism, and the environment chara erized the recent history of cognitive science.These trends have also influenced CSR: for example, the theories of embodied cognition (Geertz, 2010) and niche construction (Bu bulia, 2008) have been used to explain religion.(3) Third, new insights in systems biology can be used to rethink the concept of cultural evolution.For example, the changing view of the nature of biological replicators offers fresh per ectives on the nature of cultural replicators.At this place, let us consider the theoretical model developed by Richard Watson and Eörs Szathmáry (2016).
In their article entitled "How Can Evolution Learn?, " Watson and Szathmáry su gest that evolution is a learning process that takes place in networks.Specifica ly, they draw on the concept of neural networks in artificial inte ligence research.Neural networks in computer modeling are loosely based on how neurons work in the brain and have been used in artificial inte ligence for some decades.They have been going through a renaissance in recent years, also refer ed to as dee learning.Without delving into the details of deep learning, we can note that neural networks learn by adjusting their connection weights (based on their learning algorithms) to produce increasingly better outputs in response to inputs.We have seen that both gene re ulatory networks and the phenotype as a re ulatory system lend themselves to network theoretical modeling.Variation in these systems, due to both random and directional mutations, can be understood as adjustments of their network structures.Natural selection, Watson and Szathmáry ar ue, serves as a fee back mechanism and drives the learning process.(They also extend the model to ecological networks, which we cannot discuss at this point.)The model of neural networks and the related body of learning theory provide conceptual frameworks for understanding learning processes in various domains and raise the possibility of rethinking cultural evolution in terms of network science.In recent years, network theory started to gain tra ion in the study of religion, with emerging ap lications to social, environmental, and textual data (e.g., Ambasciano, 2016;Chalupa, 2015;Czachesz, 2013Czachesz, , 2016;;Elwert and Se lmer, 2013;Lane, 2015).Moving beyond data representation and descriptive statistics in the study of cultural networks, the evolutionary paradigm championed by Watson and Szathmáry presents itself as a new op ortunity to think about cultural evolution as a learning process on these network structures.

Conclusions
In this article, I surveyed the uses of evolutionary theory in the cognitive science of religion.While CSR relied heavily on evolutionary psychology in the beginning, it has received influences from various branches of evolutionary science during the last decade.The second part of the discussion focused e ecia ly on the use of evolutionary theory to understand culture and the controversies sur ounding the theory of cultural evolution and its use in the study of religion.In the final part of the article, I su ge ed that considering cur ent advances in evolutionary science can be e ecia ly helpful in developing an improved concept of cultural evolution.
Filosofi a Unisinos -Unisinos Journal of Philosophy -19(3):263-271, sep/dec 2018 2): (a) Inhe itance is the transmission of replicated materials from parent to offspring.(b) Development is the implementation of a program that exerts control over the phenotype.(c) Va iation arises from random changes introduced into the genetic code.(d) Adapti e population c ange is the change in the relative frequency of replicated entities (genes) under the influence of natural selection (as described above), mediated by the environment.