Synergy

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Synergy 

Synergy is an interaction or cooperation giving rise to a whole that is greater than the simple sum of its parts. The term synergy comes from the Attic Greek word συνεργία synergia from synergos, συνεργός, meaning "working together".

History

In Christian theology, synergism is the idea that salvation involves some form of cooperation between divine grace and human freedom.

The words synergy and synergetic have been used in the field of physiology since at least the middle of the 19th century:

SYN'ERGY, Synergi'a, Synenergi'a, (F.) Synergie; from συν, 'with', and εργον, 'work'. A correlation or concourse of action between different organs in health; and, according to some, in disease.

—Dunglison, Robley Medical Lexicon Blanchard and Lea, 1853

In 1896, Henri Mazel applied the term "synergy" to social psychology by writing La synergie sociale, in which he argued that Darwinian theory failed to account of "social synergy" or "social love", a collective evolutionary drive. The highest civilizations were the work not only of the elite but of the masses too; those masses must be led, however, because the crowd, a feminine and unconscious force, cannot distinguish between good and evil.

In 1909, Lester Frank Ward defined synergy as the universal constructive principle of nature:

I have characterized the social struggle as centrifugal and social solidarity as centripetal. Either alone is productive of evil consequences. Struggle is essentially destructive of the social order, while communism removes individual initiative. The one leads to disorder, the other to degeneracy. What is not seen—the truth that has no expounders—is that the wholesome, constructive movement consists in the properly ordered combination and interaction of both these principles. This is social synergy, which is a form of cosmic synergy, the universal constructive principle of nature.

—Ward, Lester F. Glimpses of the Cosmos, volume VI (1897–1912) G. P. Putnam's Sons, 1918, p. 358

Descriptions and usages

In the natural world, synergistic phenomena are ubiquitous, ranging from physics (for example, the different combinations of quarks that produce protons and neutrons) to chemistry (a popular example is water, a compound of hydrogen and oxygen), to the cooperative interactions among the genes in genomes, the division of labor in bacterial colonies, the synergies of scale in multi-cellular organisms, as well as the many different kinds of synergies produced by socially-organized groups, from honeybee colonies to wolf packs and human societies: compare stigmergy, a mechanism of indirect coordination between agents or actions that results in the self-assembly of complex systems. Even the tools and technologies that are widespread in the natural world represent important sources of synergistic effects. The tools that enabled early hominins to become systematic big-game hunters is a primordial human example.

In the context of organizational behavior, following the view that a cohesive group is more than the sum of its parts, synergy is the ability of a group to outperform even its best individual member. These conclusions are derived from the studies conducted by Jay Hall on a number of laboratory-based group ranking and prediction tasks. He found that effective groups actively looked for the points in which they disagreed and in consequence encouraged conflicts amongst the participants in the early stages of the discussion. In contrast, the ineffective groups felt a need to establish a common view quickly, used simple decision making methods such as averaging, and focused on completing the task rather than on finding solutions they could agree on. In a technical context, its meaning is a construct or collection of different elements working together to produce results not obtainable by any of the elements alone. The elements, or parts, can include people, hardware, software, facilities, policies, documents: all things required to produce system-level results. The value added by the system as a whole, beyond that contributed independently by the parts, is created primarily by the relationship among the parts, that is, how they are interconnected. In essence, a system constitutes a set of interrelated components working together with a common objective: fulfilling some designated need.

If used in a business application, synergy means that teamwork will produce an overall better result than if each person within the group were working toward the same goal individually. However, the concept of group cohesion needs to be considered. Group cohesion is that property that is inferred from the number and strength of mutual positive attitudes among members of the group. As the group becomes more cohesive, its functioning is affected in a number of ways. First, the interactions and communication between members increase. Common goals, interests and small size all contribute to this. In addition, group member satisfaction increases as the group provides friendship and support against outside threats.

There are negative aspects of group cohesion that have an effect on group decision-making and hence on group effectiveness. There are two issues arising. The risky shift phenomenon is the tendency of a group to make decisions that are riskier than those that the group would have recommended individually. Group Polarisation is when individuals in a group begin by taking a moderate stance on an issue regarding a common value and, after having discussed it, end up taking a more extreme stance.

A second, potential negative consequence of group cohesion is group think. Group think is a mode of thinking that people engage in when they are deeply involved in cohesive group, when the members' striving for unanimity overrides their motivation to appraise realistically the alternative courses of action. Studying the events of several American policy "disasters" such as the failure to anticipate the Japanese attack on Pearl Harbor (1941) and the Bay of Pigs Invasion fiasco (1961), Irving Janis argued that they were due to the cohesive nature of the committees that made the relevant decisions.

That decisions made by committees lead to failure in a simple system is noted by Dr. Chris Elliot. His case study looked at IEEE-488, an international standard set by the leading US standards body; it led to a failure of small automation systems using the IEEE-488 standard (which codified a proprietary communications standard HP-IB). But the external devices used for communication were made by two different companies, and the incompatibility between the external devices led to a financial loss for the company. He argues that systems will be safe only if they are designed, not if they emerge by chance.

The idea of a systemic approach is endorsed by the United Kingdom Health and Safety Executive. The successful performance of the health and safety management depends upon the analyzing the causes of incidents and accidents and learning correct lessons from them. The idea is that all events (not just those causing injuries) represent failures in control, and present an opportunity for learning and improvement. UK Health and Safety Executive, Successful health and safety management (1997): this book describes the principles and management practices, which provide the basis of effective health and safety management. It sets out the issues that need to be addressed, and can be used for developing improvement programs, self-audit, or self-assessment. Its message is that organizations must manage health and safety with the same degree of expertise and to the same standards as other core business activities, if they are to effectively control risks and prevent harm to people.

The term synergy was refined by R. Buckminster Fuller, who analyzed some of its implications more fully and coined the term synergetics.

• A dynamic state in which combined action is favored over the difference of individual component actions.
• Behavior of whole systems unpredicted by the behavior of their parts taken separately, known as emergent behavior.
• The cooperative action of two or more stimuli (or drugs), resulting in a different or greater response than that of the individual stimuli.

Biological sciences

Synergy of various kinds has been advanced by Peter Corning as a causal agency that can explain the progressive evolution of complexity in living systems over the course of time. According to the Synergism Hypothesis, synergistic effects have been the drivers of cooperative relationships of all kinds and at all levels in living systems. The thesis, in a nutshell, is that synergistic effects have often provided functional advantages (economic benefits) in relation to survival and reproduction that have been favored by natural selection. The cooperating parts, elements, or individuals become, in effect, functional “units” of selection in evolutionary change. Similarly, environmental systems may react in a non-linear way to perturbations, such as climate change, so that the outcome may be greater than the sum of the individual component alterations. Synergistic responses are a complicating factor in environmental modeling.

Pest synergy

Pest synergy would occur in a biological host organism population, where, for example, the introduction of parasite A may cause 10% fatalities, and parasite B may also cause 10% loss. When both parasites are present, the losses would normally be expected to total less than 20%, yet, in some cases, losses are significantly greater. In such cases, it is said that the parasites in combination have a synergistic effect.

Drug synergy

Mechanisms that may be involved in the development of synergistic effects include:

• Effect on the same cellular system (e.g. two different antibiotics like a penicillin and an aminoglycoside; penicillins damage the cell wall of gram-positive bacteria and improve the penetration of aminoglycosides).
• Bioavailability (e.g. ayahuasca (or pharmahuasca) consists of DMT combined with MAOIs that interfere with the action of the MAO enzyme and stop the breakdown of chemical compounds such as DMT).
• Reduced risk for substance abuse (e.g. lisdexamfetamine, which is a combination of the amino acid L-lysine, attached to dextroamphetamine, may have a lower liability for abuse as a recreational drug)
• Increased potency (e.g. as with other NSAIDs, combinations of aspirin and caffeine provide slightly greater pain relief than aspirin alone.).
• Prevention or delay of degradation in the body (e.g. the antibiotic Ciprofloxacin inhibits the metabolism of Theophylline).
• Slowdown of excretion (e.g. Probenecid delays the renal excretion of Penicillin and thus prolongs its effect).
• Anticounteractive action: for example, the effect of oxaliplatin and irinotecan. Oxaliplatin intercalates DNA, thereby preventing the cell from replicating DNA. Irinotecan inhibits topoisomerase 1, consequently the cytostatic effect is increased.
• Effect on the same receptor but different sites (e.g. the coadministration of benzodiazepines and barbiturates, both act by enhancing the action of GABA on GABA_A receptors, but benzodiazepines increase the frequency of channel opening, whilst barbiturates increase the channel closing time, making these two drugs dramatically enhance GABAergic neurotransmission).

More mechanisms are described in an exhaustive 2009 review.

Toxicological synergy

Toxicological synergy is of concern to the public and regulatory agencies because chemicals individually considered safe might pose unacceptable health or ecological risk in combination. Articles in scientific and lay journals include many definitions of chemical or toxicological synergy, often vague or in conflict with each other. Because toxic interactions are defined relative to the expectation under "no interaction", a determination of synergy (or antagonism) depends on what is meant by "no interaction". The United States Environmental Protection Agency has one of the more detailed and precise definitions of toxic interaction, designed to facilitate risk assessment. In their guidance documents, the no-interaction default assumption is dose addition, so synergy means a mixture response that exceeds that predicted from dose addition. The EPA emphasizes that synergy does not always make a mixture dangerous, nor does antagonism always make the mixture safe; each depends on the predicted risk under dose addition.

For example, a consequence of pesticide use is the risk of health effects. During the registration of pesticides in the United States exhaustive tests are performed to discern health effects on humans at various exposure levels. A regulatory upper limit of presence in foods is then placed on this pesticide. As long as residues in the food stay below this regulatory level, health effects are deemed highly unlikely and the food is considered safe to consume.

However, in normal agricultural practice, it is rare to use only a single pesticide. During the production of a crop, several different materials may be used. Each of them has had determined a regulatory level at which they would be considered individually safe. In many cases, a commercial pesticide is itself a combination of several chemical agents, and thus the safe levels actually represent levels of the mixture. In contrast, a combination created by the end user, such as a farmer, has rarely been tested in that combination. The potential for synergy is then unknown or estimated from data on similar combinations. This lack of information also applies to many of the chemical combinations to which humans are exposed, including residues in food, indoor air contaminants, and occupational exposures to chemicals. Some groups think that the rising rates of cancer, asthma, and other health problems may be caused by these combination exposures; others have alternative explanations. This question will likely be answered only after years of exposure by the population in general and research on chemical toxicity, usually performed on animals. Examples of pesticide synergists include Piperonyl butoxide and MGK 264.

Human synergy

Human synergy relates to human interaction and teamwork. For example, say person A alone is too short to reach an apple on a tree and person B is too short as well. Once person B sits on the shoulders of person A, they are tall enough to reach the apple. In this example, the product of their synergy would be one apple. Another case would be two politicians. If each is able to gather one million votes on their own, but together they were able to appeal to 2.5 million voters, their synergy would have produced 500,000 more votes than had they each worked independently. A song is also a good example of human synergy, taking more than one musical part and putting them together to create a song that has a much more dramatic effect than each of the parts when played individually.

A third form of human synergy is when one person is able to complete two separate tasks by doing one action, for example, if a person were asked by a teacher and his boss at work to write an essay on how he could improve his work. A more visual example of this synergy is a drummer using four separate rhythms to create one drum beat.

Synergy usually arises when two persons with different complementary skills cooperate. In business, cooperation of people with organizational and technical skills happens very often. In general, the most common reason why people cooperate is that it brings a synergy. On the other hand, people tend to specialize just to be able to form groups with high synergy (see also division of labor and teamwork).

Example: Two teams in System Administration working together to combine technical and organizational skills in order to better the client experience, thus creating synergy. Counter-examples can be found in books like The Mythical Man-Month, in which the addition of additional team members is shown to have negative effects on productivity.

Organismic computing is an approach to improving group efficacy by increasing synergy in human groups via technological means.

When synergy occurs in the work place, the individuals involved get to work in a positive and supportive working environment. When individuals get to work in environments such as these, the company reaps the benefits. The authors of Creating the Best Workplace on Earth Rob Goffee and Gareth Jones, state that "highly engaged employees are, on average, 50% more likely to exceed expectations that the least-engaged workers. And companies with highly engaged people outperform firms with the most disengaged folks- by 54% in employee retention, by 89% in customer satisfaction, and by fourfold in revenue growth (Goffee & Jones, pg. 100)." Also, those that are able to be open about their views on the company, and have confidence that they will be heard, are likely to be a more organized employee who helps his/ her fellow team members succeed.

Corporate synergy

Corporate synergy occurs when corporations interact congruently. A corporate synergy refers to a financial benefit that a corporation expects to realize when it merges with or acquires another corporation. This type of synergy is a nearly ubiquitous feature of a corporate acquisition and is a negotiating point between the buyer and seller that impacts the final price both parties agree to. There are distinct types of corporate synergies, as follows.

Marketing

A marketing synergy refers to the use of information campaigns, studies, and scientific discovery or experimentation for research and development. This promotes the sale of products for varied use or off-market sales as well as development of marketing tools and in several cases exaggeration of effects. It is also often a meaningless buzzword used by corporate leaders.

Revenue

A revenue synergy refers to the opportunity of a combined corporate entity to generate more revenue than its two predecessor stand-alone companies would be able to generate. For example, if company A sells product X through its sales force, company B sells product Y, and company A decides to buy company B, then the new company could use each salesperson to sell products X and Y, thereby increasing the revenue that each salesperson generates for the company.

In media revenue, synergy is the promotion and sale of a product throughout the various subsidiaries of a media conglomerate, e.g. films, soundtracks, or video games.

Financial

Financial synergy gained by the combined firm is a result of number of benefits which flow to the entity as a consequence of acquisition and merger. These benefits may be:

Cash slack

This is when a firm having a number of cash extensive projects acquires a firm which is cash-rich, thus enabling the new combined firm to enjoy the profits from investing the cash of one firm in the projects of the other.

Debt capacity

If two firms have no or little capacity to carry debt before individually, it is possible for them to join and gain the capacity to carry the debt through decreased gearing (leverage). This creates value for the firm, as debt is thought to be a cheaper source of finance.

Tax benefits

It is possible for one firm to have unused tax benefits which might be offset against the profits of another after combination, thus resulting in less tax being paid. However this greatly depends on the tax law of the country.

Management

Synergy in management and in relation to teamwork refers to the combined effort of individuals as participants of the team. The condition that exists when the organization's parts interact to produce a joint effect that is greater than the sum of the parts acting alone. Positive or negative synergies can exist. In these cases, positive synergy has positive effects such as improved efficiency in operations, greater exploitation of opportunities, and improved utilization of resources. Negative synergy on the other hand has negative effects such as: reduced efficiency of operations, decrease in quality, underutilization of resources and disequilibrium with the external environment.

Cost

A cost synergy refers to the opportunity of a combined corporate entity to reduce or eliminate expenses associated with running a business. Cost synergies are realized by eliminating positions that are viewed as duplicate within the merged entity. Examples include the headquarters office of one of the predecessor companies, certain executives, the human resources department, or other employees of the predecessor companies. This is related to the economic concept of economies of scale.

Synergistic action in economy

The synergistic action of the economic players lies within the economic phenomenon's profundity. The synergistic action gives different dimensions to competitiveness, strategy and network identity becoming an unconventional "weapon" which belongs to those who exploit the economic systems’ potential in depth.

Synergistic determinants

The synergistic gravity equation (SYNGEq), according to its complex “title”, represents a synthesis of the endogenous and exogenous factors which determine the private and non-private economic decision makers to call to actions of synergistic exploitation of the economic network in which they operate. That is to say, SYNGEq constitutes a big picture of the factors/motivations which determine the entrepreneurs to contour an active synergistic network. SYNGEq includes both factors which character is changing over time (such as the competitive conditions), as well as classics factors, such as the imperative of the access to resources of the collaboration and the quick answers. The synergistic gravity equation (SINGEq) comes to be represented by the formula:

∑SYN.Act = ∑R-*I(CRed+COOP++A^Unimit.)*V(Cust.+Info.)*cc

where:

• ∑SYN.Act = the sum of the synergistic actions adopted (by the economic actor)
• ∑ R- = the amount of unpurchased but necessary resources
• ICRed = the imperative for cost reductions
• ICOOP+ = the imperative for deep cooperation (functional interdependence)
• IA^Unimit. = the imperative for purchasing unimitable competitive advantages (for the economic actor)
• VCust = the necessity of customer value in purchasing future profits and competitive advantages VInfo = the necessity of informational value in purchasing future profits and competitive advantages
• cc = the specific competitive conditions in which the economic actor operates

Synergistic networks and systems

The synergistic network represents an integrated part of the economic system which, through the coordination and control functions (of the undertaken economic actions), agrees synergies. The networks which promote synergistic actions can be divided in horizontal synergistic networks and vertical synergistic networks.

Synergy effects

The synergy effects are difficult (even impossible) to imitate by competitors and difficult to reproduce by their authors because these effects depend on the combination of factors with time-varying characteristics. The synergy effects are often called "synergistic benefits", representing the direct and implied result of the developed/adopted synergistic actions.

Computers

Synergy can also be defined as the combination of human strengths and computer strengths, such as advanced chess. Computers can process data much more quickly than humans, but lack the ability to respond meaningfully to arbitrary stimuli.

Synergy in literature

Etymologically, the "synergy" term was first used around 1600, deriving from the Greek word “synergos”, which means “to work together” or “to cooperate”. If during this period the synergy concept was mainly used in the theological field (describing “the cooperation of human effort with divine will”), in the 19th and 20th centuries, "synergy" was promoted in physics and biochemistry, being implemented in the study of the open economic systems only in the 1960 and 1970s.

In 1938, J. R. R. Tolkien wrote an essay titled On Fairy Stores, delivered at an Andrew Lang Lecture, and reprinted in his book, The Tolkien Reader, published in 1966. In it, he made two references to synergy, although he did not use that term. He wrote:

Faerie cannot be caught in a net of words; for it is one of its qualities to be indescribable, though not imperceptible. It has many ingredients, but analysis will not necessarily discover the secret of the whole.

And more succinctly, in a footnote, about the "part of producing the web of an intricate story", he wrote:

It is indeed easier to unravel a single thread — an incident, a name, a motive — than to trace the history of any picture defined by many threads. For with the picture in the tapestry a new element has come in: the picture is greater than, and not explained by, the sum of the component threads.

Synergy as a book

Synergy, a book: DION, Eric (2017), Synergy; A Theoretical Model of Canada's Comprehensive Approach, iUniverse, 308 pp.

Synergy in the media

The informational synergies which can be applied also in media involve a compression of transmission, access and use of information’s time, the flows, circuits and means of handling information being based on a complementary, integrated, transparent and coordinated use of knowledge.

In media economics, synergy is the promotion and sale of a product (and all its versions) throughout the various subsidiaries of a media conglomerate, e.g. films, soundtracks or video games. Walt Disney pioneered synergistic marketing techniques in the 1930s by granting dozens of firms the right to use his Mickey Mouse character in products and ads, and continued to market Disney media through licensing arrangements. These products can help advertise the film itself and thus help to increase the film's sales. For example, the Spider-Man films had toys of webshooters and figures of the characters made, as well as posters and games. The NBC sitcom 30 Rock often shows the power of synergy, while also poking fun at the use of the term in the corporate world. There are also different forms of synergy in popular card games like Magic: The Gathering, Yu-Gi-Oh!, Cardfight!! Vanguard, and Future Card Buddyfight.

Information theory

When multiple sources of information taken together provide more information than the sum of the information provided by each source alone, there is said to be a synergy in the sources. This in contrast to the case in which the sources provide less information, in which case there is said to be a redundancy in the sources.

Punctuated equilibrium

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Punctuated_equilibrium 

 

 

 

The punctuated equilibrium model (top) consists of morphological stability followed by rare bursts of evolutionary change via rapid cladogenesis. It is contrasted (below) to phyletic gradualism, the more gradual, continuous model of evolution. On diagram we see equilibrium states separated by a jump phase.

In evolutionary biology, punctuated equilibrium (also called punctuated equilibria) is a theory that proposes that once a species appears in the fossil record, the population will become stable, showing little evolutionary change for most of its geological history. This state of little or no morphological change is called stasis. When significant evolutionary change occurs, the theory proposes that it is generally restricted to rare and geologically rapid events of branching speciation called cladogenesis. Cladogenesis is the process by which a species splits into two distinct species, rather than one species gradually transforming into another.

Punctuated equilibrium is commonly contrasted against phyletic gradualism, the idea that evolution generally occurs uniformly and by the steady and gradual transformation of whole lineages (called anagenesis). In this view, evolution is seen as generally smooth and continuous.

In 1972, paleontologists Niles Eldredge and Stephen Jay Gould published a landmark paper developing their theory and called it punctuated equilibria. Their paper built upon Ernst Mayr's model of geographic speciation, I. Michael Lerner's theories of developmental and genetic homeostasis, and their own empirical research. Eldredge and Gould proposed that the degree of gradualism commonly attributed to Charles Darwin is virtually nonexistent in the fossil record, and that stasis dominates the history of most fossil species.

History

Punctuated equilibrium originated as a logical consequence of Ernst Mayr's concept of genetic revolutions by allopatric and especially peripatric speciation as applied to the fossil record. Although the sudden appearance of species and its relationship to speciation was proposed and identified by Mayr in 1954, historians of science generally recognize the 1972 Eldredge and Gould paper as the basis of the new paleobiological research program. Punctuated equilibrium differs from Mayr's ideas mainly in that Eldredge and Gould placed considerably greater emphasis on stasis, whereas Mayr was concerned with explaining the morphological discontinuity (or "sudden jumps") found in the fossil record. Mayr later complimented Eldredge and Gould's paper, stating that evolutionary stasis had been "unexpected by most evolutionary biologists" and that punctuated equilibrium "had a major impact on paleontology and evolutionary biology."

A year before their 1972 Eldredge and Gould paper, Niles Eldredge published a paper in the journal Evolution which suggested that gradual evolution was seldom seen in the fossil record and argued that Ernst Mayr's standard mechanism of allopatric speciation might suggest a possible resolution.

The Eldredge and Gould paper was presented at the Annual Meeting of the Geological Society of America in 1971. The symposium focused its attention on how modern microevolutionary studies could revitalize various aspects of paleontology and macroevolution. Tom Schopf, who organized that year's meeting, assigned Gould the topic of speciation. Gould recalls that "Eldredge's 1971 publication [on Paleozoic trilobites] had presented the only new and interesting ideas on the paleontological implications of the subject—so I asked Schopf if we could present the paper jointly." According to Gould "the ideas came mostly from Niles, with yours truly acting as a sounding board and eventual scribe. I coined the term punctuated equilibrium and wrote most of our 1972 paper, but Niles is the proper first author in our pairing of Eldredge and Gould." In his book Time Frames Eldredge recalls that after much discussion the pair "each wrote roughly half. Some of the parts that would seem obviously the work of one of us were actually first penned by the other—I remember for example, writing the section on Gould's snails. Other parts are harder to reconstruct. Gould edited the entire manuscript for better consistency. We sent it in, and Schopf reacted strongly against it—thus signaling the tenor of the reaction it has engendered, though for shifting reasons, down to the present day."

John Wilkins and Gareth Nelson have argued that French architect Pierre Trémaux proposed an "anticipation of the theory of punctuated equilibrium of Gould and Eldredge."

Evidence from the fossil record

The fossil record includes well documented examples of both phyletic gradualism and punctuational evolution. As such, much debate persists over the prominence of stasis in the fossil record. Before punctuated equilibrium, most evolutionists considered stasis to be rare or unimportant. The paleontologist George Gaylord Simpson, for example, believed that phyletic gradual evolution (called horotely in his terminology) comprised 90% of evolution. More modern studies, including a meta-analysis examining 58 published studies on speciation patterns in the fossil record showed that 71% of species exhibited stasis, and 63% were associated with punctuated patterns of evolutionary change. According to Michael Benton, "it seems clear then that stasis is common, and that had not been predicted from modern genetic studies." A paramount example of evolutionary stasis is the fern Osmunda claytoniana. Based on paleontological evidence it has remained unchanged, even at the level of fossilized nuclei and chromosomes, for at least 180 million years.

Theoretical mechanisms

Punctuational change

When Eldredge and Gould published their 1972 paper, allopatric speciation was considered the "standard" model of speciation. This model was popularized by Ernst Mayr in his 1954 paper "Change of genetic environment and evolution," and his classic volume Animal Species and Evolution (1963).

Allopatric speciation suggests that species with large central populations are stabilized by their large volume and the process of gene flow. New and even beneficial mutations are diluted by the population's large size and are unable to reach fixation, due to such factors as constantly changing environments. If this is the case, then the transformation of whole lineages should be rare, as the fossil record indicates. Smaller populations on the other hand, which are isolated from the parental stock, are decoupled from the homogenizing effects of gene flow. In addition, pressure from natural selection is especially intense, as peripheral isolated populations exist at the outer edges of ecological tolerance. If most evolution happens in these rare instances of allopatric speciation then evidence of gradual evolution in the fossil record should be rare. This hypothesis was alluded to by Mayr in the closing paragraph of his 1954 paper:

Rapidly evolving peripherally isolated populations may be the place of origin of many evolutionary novelties. Their isolation and comparatively small size may explain phenomena of rapid evolution and lack of documentation in the fossil record, hitherto puzzling to the palaeontologist.

Although punctuated equilibrium generally applies to sexually reproducing organisms, some biologists have applied the model to non-sexual species like viruses, which cannot be stabilized by conventional gene flow. As time went on biologists like Gould moved away from wedding punctuated equilibrium to allopatric speciation, particularly as evidence accumulated in support of other modes of speciation. Gould, for example, was particularly attracted to Douglas Futuyma's work on the importance of reproductive isolating mechanisms.

Stasis

Many hypotheses have been proposed to explain the putative causes of stasis. Gould was initially attracted to I. Michael Lerner's theories of developmental and genetic homeostasis. However this hypothesis was rejected over time, as evidence accumulated against it. Other plausible mechanisms which have been suggested include: habitat tracking, stabilizing selection, the Stenseth-Maynard Smith stability hypothesis, constraints imposed by the nature of subdivided populations, normalizing clade selection, and koinophilia.

Evidence for stasis has also been corroborated from the genetics of sibling species, species which are morphologically indistinguishable, but whose proteins have diverged sufficiently to suggest they have been separated for millions of years. Fossil evidence of reproductively isolated extant species of sympatric Olive Shells (Amalda sp.) also confirm morphological stasis in multiple lineages over three million years.

According to Gould, "stasis may emerge as the theory's most important contribution to evolutionary science." Philosopher Kim Sterelny in clarifying the meaning of stasis adds, "In claiming that species typically undergo no further evolutionary change once speciation is complete, they are not claiming that there is no change at all between one generation and the next. Lineages do change. But the change between generations does not accumulate. Instead, over time, the species wobbles about its phenotypic mean. Jonathan Weiner's The Beak of the Finch describes this very process."

Hierarchical evolution

Punctuated equilibrium has also been cited as contributing to the hypothesis that species are Darwinian individuals, and not just classes, thereby providing a stronger framework for a hierarchical theory of evolution.

Common misconceptions

Much confusion has arisen over what proponents of punctuated equilibrium actually argued, what mechanisms they advocated, how fast the punctuations were, what taxonomic scale their theory applied to, how revolutionary their claims were intended to be, and how punctuated equilibrium related to other ideas like saltationism, quantum evolution, and mass extinction.

Saltationism

Alternative explanations for the punctuated pattern of evolution observed in the fossil record. Both macromutation and relatively rapid episodes of gradual evolution could give the appearance of instantaneous change, since 10,000 years seldom registers in the geological record.

The punctuational nature of punctuated equilibrium has engendered perhaps the most confusion over Eldredge and Gould's theory. Gould's sympathetic treatment of Richard Goldschmidt, the controversial geneticist who advocated the idea of "hopeful monsters," led some biologists to conclude that Gould's punctuations were occurring in single-generation jumps. This interpretation has frequently been used by creationists to characterize the weakness of the paleontological record, and to portray contemporary evolutionary biology as advancing neo-saltationism. In an often quoted remark, Gould stated, "Since we proposed punctuated equilibria to explain trends, it is infuriating to be quoted again and again by creationists—whether through design or stupidity, I do not know—as admitting that the fossil record includes no transitional forms. Transitional forms are generally lacking at the species level, but they are abundant between larger groups." Although there exist some debate over how long the punctuations last, supporters of punctuated equilibrium generally place the figure between 50,000 and 100,000 years.

Quantum evolution

Quantum evolution was a controversial hypothesis advanced by Columbia University paleontologist George Gaylord Simpson, who was regarded by Gould as "the greatest and most biologically astute paleontologist of the twentieth century." Simpson's conjecture was that according to the geological record, on very rare occasions evolution would proceed very rapidly to form entirely new families, orders, and classes of organisms. This hypothesis differs from punctuated equilibrium in several respects. First, punctuated equilibrium was more modest in scope, in that it was addressing evolution specifically at the species level. Simpson's idea was principally concerned with evolution at higher taxonomic groups. Second, Eldredge and Gould relied upon a different mechanism. Where Simpson relied upon a synergistic interaction between genetic drift and a shift in the adaptive fitness landscape, Eldredge and Gould relied upon ordinary speciation, particularly Ernst Mayr's concept of allopatric speciation. Lastly, and perhaps most significantly, quantum evolution took no position on the issue of stasis. Although Simpson acknowledged the existence of stasis in what he called the bradytelic mode, he considered it (along with rapid evolution) to be unimportant in the larger scope of evolution. In his Major Features of Evolution Simpson stated, "Evolutionary change is so nearly the universal rule that a state of motion is, figuratively, normal in evolving populations. The state of rest, as in bradytely, is the exception and it seems that some restraint or force must be required to maintain it." Despite such differences between the two models, earlier critiques—from such eminent commentators as Sewall Wright as well as Simpson himself—have argued that punctuated equilibrium is little more than quantum evolution relabeled.

Multiple meanings of gradualism

Punctuated equilibrium is often portrayed to oppose the concept of gradualism, when it is actually a form of gradualism. This is because even though evolutionary change appears instantaneous between geological sedimentary layers, change is still occurring incrementally, with no great change from one generation to the next. To this end, Gould later commented that "Most of our paleontological colleagues missed this insight because they had not studied evolutionary theory and either did not know about allopatric speciation or had not considered its translation to geological time. Our evolutionary colleagues also failed to grasp the implication(s), primarily because they did not think at geological scales".

Richard Dawkins dedicated a chapter in The Blind Watchmaker to correcting, in his view, the wide confusion regarding rates of change. His first point is to argue that phyletic gradualism—understood in the sense that evolution proceeds at a single uniform rate of speed, called "constant speedism" by Dawkins—is a "caricature of Darwinism" and "does not really exist". His second argument, which follows from the first, is that once the caricature of "constant speedism" is dismissed, we are left with one logical alternative, which Dawkins terms "variable speedism". Variable speedism may also be distinguished one of two ways: "discrete variable speedism" and "continuously variable speedism". Eldredge and Gould, proposing that evolution jumps between stability and relative rapidity, are described as "discrete variable speedists", and "in this respect they are genuinely radical." They assert that evolution generally proceeds in bursts, or not at all. "Continuously variable speedists", on the other hand, advance that "evolutionary rates fluctuate continuously from very fast to very slow and stop, with all intermediates. They see no particular reason to emphasize certain speeds more than others. In particular, stasis, to them, is just an extreme case of ultra-slow evolution. To a punctuationist, there is something very special about stasis." Dawkins therefore commits himself here to an empirical claim about the geological record, in contrast to his earlier claim that "The paleontological evidence can be argued about, and I am not qualified to judge it." It is this particular commitment that Eldredge and Gould have aimed to overturn.

Criticism

Richard Dawkins regards the apparent gaps represented in the fossil record to document migratory events rather than evolutionary events. According to Dawkins, evolution certainly occurred but "probably gradually" elsewhere. However, the punctuational equilibrium model may still be inferred from both the observation of stasis and examples of rapid and episodic speciation events documented in the fossil record.

Dawkins also emphasizes that punctuated equilibrium has been "oversold by some journalists", but partly due to Eldredge and Gould's "later writings". Dawkins contends that the hypothesis "does not deserve a particularly large measure of publicity". It is a "minor gloss," an "interesting but minor wrinkle on the surface of neo-Darwinian theory," and "lies firmly within the neo-Darwinian synthesis".

In his book Darwin's Dangerous Idea, philosopher Daniel Dennett is especially critical of Gould's presentation of punctuated equilibrium. Dennett argues that Gould alternated between revolutionary and conservative claims, and that each time Gould made a revolutionary statement—or appeared to do so—he was criticized, and thus retreated to a traditional neo-Darwinian position. Gould responded to Dennett's claims in The New York Review of Books, and in his technical volume The Structure of Evolutionary Theory.

English professor Heidi Scott argues that Gould's talent for writing vivid prose, his use of metaphor, and his success in building a popular audience of nonspecialist readers altered the "climate of specialized scientific discourse" favorably in his promotion of punctuated equilibrium. While Gould is celebrated for the color and energy of his prose, as well as his interdisciplinary knowledge, critics such as Scott, Richard Dawkins, and Daniel Dennett have concerns that the theory has gained undeserved credence among non-scientists because of Gould's rhetorical skills. Philosopher John Lyne and biologist Henry Howe believed punctuated equilibrium's success has much more to do with the nature of the geological record than the nature of Gould's rhetoric. They state, a "re-analysis of existing fossil data has shown, to the increasing satisfaction of the paleontological community, that Eldredge and Gould were correct in identifying periods of evolutionary stasis which are interrupted by much shorter periods of evolutionary change."

Some critics jokingly referred to the theory of punctuated equilibrium as "evolution by jerks", which reportedly prompted punctuationists to describe phyletic gradualism as "evolution by creeps."

Darwin's theory

The sudden appearance of most species in the geologic record and the lack of evidence of substantial gradual change in most species—from their initial appearance until their extinction—has long been noted, including by Charles Darwin who appealed to the imperfection of the record as the favored explanation. When presenting his ideas against the prevailing influences of catastrophism and progressive creationism, which envisaged species being supernaturally created at intervals, Darwin needed to forcefully stress the gradual nature of evolution in accordance with the gradualism promoted by his friend Charles Lyell. He privately expressed concern, noting in the margin of his 1844 Essay, "Better begin with this: If species really, after catastrophes, created in showers world over, my theory false."

It is often incorrectly assumed that he insisted that the rate of change must be constant, or nearly so, but even the first edition of On the Origin of Species states that "Species of different genera and classes have not changed at the same rate, or in the same degree. In the oldest tertiary beds a few living shells may still be found in the midst of a multitude of extinct forms... The Silurian Lingula differs but little from the living species of this genus". Lingula is among the few brachiopods surviving today but also known from fossils over 500 million years old. In the fourth edition (1866) of On the Origin of Species Darwin wrote that "the periods during which species have undergone modification, though long as measured in years, have probably been short in comparison with the periods during which they retain the same form." Thus punctuationism in general is consistent with Darwin's conception of evolution.

According to early versions of punctuated equilibrium, "peripheral isolates" are considered to be of critical importance for speciation. However, Darwin wrote, "I can by no means agree ... that immigration and isolation are necessary elements.... Although isolation is of great importance in the production of new species, on the whole I am inclined to believe that largeness of area is still more important, especially for the production of species which shall prove capable of enduring for a long period, and of spreading widely."

The importance of isolation in forming species had played a significant part in Darwin's early thinking, as shown in his Essay of 1844. But by the time he wrote the Origin he had downplayed its importance. He explained the reasons for his revised view as follows:

Throughout a great and open area, not only will there be a greater chance of favourable variations, arising from the large number of individuals of the same species there supported, but the conditions of life are much more complex from the large number of already existing species; and if some of these species become modified and improved, others will have to be improved in a corresponding degree, or they will be exterminated. Each new form, also, as soon as it has been improved, will be able to spread over the open and continuous area, and will thus come into competition with many other forms ... the new forms produced on large areas, which have already been victorious over many competitors, will be those that will spread most widely, and will give rise to the greatest number of new varieties and species. They will thus play a more important role in the changing history of the organic world.

Thus punctuated equilibrium is incongruous with some of Darwin's ideas regarding the specific mechanisms of evolution, but generally accords with Darwin's theory of evolution by natural selection.

Supplemental modes of rapid evolution

Recent work in developmental biology has identified dynamical and physical mechanisms of tissue morphogenesis that may underlie abrupt morphological transitions during evolution. Consequently, consideration of mechanisms of phylogenetic change that have been found in reality to be non-gradual is increasingly common in the field of evolutionary developmental biology, particularly in studies of the origin of morphological novelty. A description of such mechanisms can be found in the multi-authored volume Origination of Organismal Form (MIT Press; 2003).

Language change

In linguistics, R. M. W. Dixon has proposed a punctuated equilibrium model for language histories, with reference particularly to the prehistory of the indigenous languages of Australia and his objections to the proposed Pama–Nyungan language family there. Although his model has raised considerable interest, it does not command majority support within linguistics.

Separately, recent work using computational phylogenetic methods claims to show that punctuational bursts play an important factor when languages split from one another, accounting for anywhere from 10 to 33% of the total divergence in vocabulary.

Mythology

Punctuational evolution has been argued to explain changes in folktales and mythology over time.

Microevolution

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Microevolution 

Microevolution is the change in allele frequencies that occurs over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift. This change happens over a relatively short (in evolutionary terms) amount of time compared to the changes termed macroevolution.

Population genetics is the branch of biology that provides the mathematical structure for the study of the process of microevolution. Ecological genetics concerns itself with observing microevolution in the wild. Typically, observable instances of evolution are examples of microevolution; for example, bacterial strains that have antibiotic resistance.

Microevolution may lead to speciation, which provides the raw material for macroevolution.

Difference from macroevolution

Macroevolution is guided by sorting of interspecific variation ("species selection"), as opposed to sorting of intraspecific variation in microevolution. Species selection may occur as (a) effect-macroevolution, where organism-level traits (aggregate traits) affect speciation and extinction rates, and (b) strict-sense species selection, where species-level traits (e.g. geographical range) affect speciation and extinction rates. Macroevolution does not produce evolutionary novelties, but it determines their proliferation within the clades in which they evolved, and it adds species-level traits as non-organismic factors of sorting to this process.

Four processes

Mutation

Duplication of part of a chromosome

Mutations are changes in the DNA sequence of a cell's genome and are caused by radiation, viruses, transposons and mutagenic chemicals, as well as errors that occur during meiosis or DNA replication. Errors are introduced particularly often in the process of DNA replication, in the polymerization of the second strand. These errors can also be induced by the organism itself, by cellular processes such as hypermutation. Mutations can affect the phenotype of an organism, especially if they occur within the protein coding sequence of a gene. Error rates are usually very low—1 error in every 10–100 million bases—due to the proofreading ability of DNA polymerases. (Without proofreading error rates are a thousandfold higher; because many viruses rely on DNA and RNA polymerases that lack proofreading ability, they experience higher mutation rates.) Processes that increase the rate of changes in DNA are called mutagenic: mutagenic chemicals promote errors in DNA replication, often by interfering with the structure of base-pairing, while UV radiation induces mutations by causing damage to the DNA structure. Chemical damage to DNA occurs naturally as well, and cells use DNA repair mechanisms to repair mismatches and breaks in DNA—nevertheless, the repair sometimes fails to return the DNA to its original sequence.

In organisms that use chromosomal crossover to exchange DNA and recombine genes, errors in alignment during meiosis can also cause mutations. Errors in crossover are especially likely when similar sequences cause partner chromosomes to adopt a mistaken alignment making some regions in genomes more prone to mutating in this way. These errors create large structural changes in DNA sequence—duplications, inversions or deletions of entire regions, or the accidental exchanging of whole parts between different chromosomes (called translocation).

Mutation can result in several different types of change in DNA sequences; these can either have no effect, alter the product of a gene, or prevent the gene from functioning. Studies in the fly Drosophila melanogaster suggest that if a mutation changes a protein produced by a gene, this will probably be harmful, with about 70 percent of these mutations having damaging effects, and the remainder being either neutral or weakly beneficial. Due to the damaging effects that mutations can have on cells, organisms have evolved mechanisms such as DNA repair to remove mutations. Therefore, the optimal mutation rate for a species is a trade-off between costs of a high mutation rate, such as deleterious mutations, and the metabolic costs of maintaining systems to reduce the mutation rate, such as DNA repair enzymes. Viruses that use RNA as their genetic material have rapid mutation rates, which can be an advantage since these viruses will evolve constantly and rapidly, and thus evade the defensive responses of e.g. the human immune system.

Mutations can involve large sections of DNA becoming duplicated, usually through genetic recombination. These duplications are a major source of raw material for evolving new genes, with tens to hundreds of genes duplicated in animal genomes every million years. Most genes belong to larger families of genes of shared ancestry. Novel genes are produced by several methods, commonly through the duplication and mutation of an ancestral gene, or by recombining parts of different genes to form new combinations with new functions.

Here, domains act as modules, each with a particular and independent function, that can be mixed together to produce genes encoding new proteins with novel properties. For example, the human eye uses four genes to make structures that sense light: three for color vision and one for night vision; all four arose from a single ancestral gene. Another advantage of duplicating a gene (or even an entire genome) is that this increases redundancy; this allows one gene in the pair to acquire a new function while the other copy performs the original function. Other types of mutation occasionally create new genes from previously noncoding DNA.

Selection

Selection is the process by which heritable traits that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations.

It is sometimes valuable to distinguish between naturally occurring selection, natural selection, and selection that is a manifestation of choices made by humans, artificial selection. This distinction is rather diffuse. Natural selection is nevertheless the dominant part of selection.

Natural selection of a population for dark coloration.

The natural genetic variation within a population of organisms means that some individuals will survive more successfully than others in their current environment. Factors which affect reproductive success are also important, an issue which Charles Darwin developed in his ideas on sexual selection.

Natural selection acts on the phenotype, or the observable characteristics of an organism, but the genetic (heritable) basis of any phenotype which gives a reproductive advantage will become more common in a population (see allele frequency). Over time, this process can result in adaptations that specialize organisms for particular ecological niches and may eventually result in the speciation (the emergence of new species).

Natural selection is one of the cornerstones of modern biology. The term was introduced by Darwin in his groundbreaking 1859 book On the Origin of Species, in which natural selection was described by analogy to artificial selection, a process by which animals and plants with traits considered desirable by human breeders are systematically favored for reproduction. The concept of natural selection was originally developed in the absence of a valid theory of heredity; at the time of Darwin's writing, nothing was known of modern genetics. The union of traditional Darwinian evolution with subsequent discoveries in classical and molecular genetics is termed the modern evolutionary synthesis. Natural selection remains the primary explanation for adaptive evolution.

Genetic drift

Ten simulations of random genetic drift of a single given allele with an initial frequency distribution 0.5 measured over the course of 50 generations, repeated in three reproductively synchronous populations of different sizes. In general, alleles drift to loss or fixation (frequency of 0.0 or 1.0) significantly faster in smaller populations.

Genetic drift is the change in the relative frequency in which a gene variant (allele) occurs in a population due to random sampling. That is, the alleles in the offspring in the population are a random sample of those in the parents. And chance has a role in determining whether a given individual survives and reproduces. A population's allele frequency is the fraction or percentage of its gene copies compared to the total number of gene alleles that share a particular form.

Genetic drift is an evolutionary process which leads to changes in allele frequencies over time. It may cause gene variants to disappear completely, and thereby reduce genetic variability. In contrast to natural selection, which makes gene variants more common or less common depending on their reproductive success, the changes due to genetic drift are not driven by environmental or adaptive pressures, and may be beneficial, neutral, or detrimental to reproductive success.

The effect of genetic drift is larger in small populations, and smaller in large populations. Vigorous debates wage among scientists over the relative importance of genetic drift compared with natural selection. Ronald Fisher held the view that genetic drift plays at the most a minor role in evolution, and this remained the dominant view for several decades. In 1968 Motoo Kimura rekindled the debate with his neutral theory of molecular evolution which claims that most of the changes in the genetic material are caused by genetic drift. The predictions of neutral theory, based on genetic drift, do not fit recent data on whole genomes well: these data suggest that the frequencies of neutral alleles change primarily due to selection at linked sites, rather than due to genetic drift by means of sampling error.

Gene flow

Gene flow is the exchange of genes between populations, which are usually of the same species. Examples of gene flow within a species include the migration and then breeding of organisms, or the exchange of pollen. Gene transfer between species includes the formation of hybrid organisms and horizontal gene transfer.

Migration into or out of a population can change allele frequencies, as well as introducing genetic variation into a population. Immigration may add new genetic material to the established gene pool of a population. Conversely, emigration may remove genetic material. As barriers to reproduction between two diverging populations are required for the populations to become new species, gene flow may slow this process by spreading genetic differences between the populations. Gene flow is hindered by mountain ranges, oceans and deserts or even man-made structures such as the Great Wall of China, which has hindered the flow of plant genes.

Depending on how far two species have diverged since their most recent common ancestor, it may still be possible for them to produce offspring, as with horses and donkeys mating to produce mules. Such hybrids are generally infertile, due to the two different sets of chromosomes being unable to pair up during meiosis. In this case, closely related species may regularly interbreed, but hybrids will be selected against and the species will remain distinct. However, viable hybrids are occasionally formed and these new species can either have properties intermediate between their parent species, or possess a totally new phenotype. The importance of hybridization in developing new species of animals is unclear, although cases have been seen in many types of animals, with the gray tree frog being a particularly well-studied example.

Hybridization is, however, an important means of speciation in plants, since polyploidy (having more than two copies of each chromosome) is tolerated in plants more readily than in animals. Polyploidy is important in hybrids as it allows reproduction, with the two different sets of chromosomes each being able to pair with an identical partner during meiosis. Polyploid hybrids also have more genetic diversity, which allows them to avoid inbreeding depression in small populations.

Horizontal gene transfer is the transfer of genetic material from one organism to another organism that is not its offspring; this is most common among bacteria. In medicine, this contributes to the spread of antibiotic resistance, as when one bacteria acquires resistance genes it can rapidly transfer them to other species. Horizontal transfer of genes from bacteria to eukaryotes such as the yeast Saccharomyces cerevisiae and the adzuki bean beetle Callosobruchus chinensis may also have occurred. An example of larger-scale transfers are the eukaryotic bdelloid rotifers, which appear to have received a range of genes from bacteria, fungi, and plants. Viruses can also carry DNA between organisms, allowing transfer of genes even across biological domains. Large-scale gene transfer has also occurred between the ancestors of eukaryotic cells and prokaryotes, during the acquisition of chloroplasts and mitochondria.

Gene flow is the transfer of alleles from one population to another.

Migration into or out of a population may be responsible for a marked change in allele frequencies. Immigration may also result in the addition of new genetic variants to the established gene pool of a particular species or population.

There are a number of factors that affect the rate of gene flow between different populations. One of the most significant factors is mobility, as greater mobility of an individual tends to give it greater migratory potential. Animals tend to be more mobile than plants, although pollen and seeds may be carried great distances by animals or wind.

Maintained gene flow between two populations can also lead to a combination of the two gene pools, reducing the genetic variation between the two groups. It is for this reason that gene flow strongly acts against speciation, by recombining the gene pools of the groups, and thus, repairing the developing differences in genetic variation that would have led to full speciation and creation of daughter species.

For example, if a species of grass grows on both sides of a highway, pollen is likely to be transported from one side to the other and vice versa. If this pollen is able to fertilise the plant where it ends up and produce viable offspring, then the alleles in the pollen have effectively been able to move from the population on one side of the highway to the other.

Origin and extended use of the term

Origin

The term microevolution was first used by botanist Robert Greenleaf Leavitt in the journal Botanical Gazette in 1909, addressing what he called the "mystery" of how formlessness gives rise to form.

..The production of form from formlessness in the egg-derived individual, the multiplication of parts and the orderly creation of diversity among them, in an actual evolution, of which anyone may ascertain the facts, but of which no one has dissipated the mystery in any significant measure. This microevolution forms an integral part of the grand evolution problem and lies at the base of it, so that we shall have to understand the minor process before we can thoroughly comprehend the more general one...

However, Leavitt was using the term to describe what we would now call developmental biology; it was not until Russian Entomologist Yuri Filipchenko used the terms "macroevolution" and "microevolution" in 1927 in his German language work, Variabilität und Variation, that it attained its modern usage. The term was later brought into the English-speaking world by Filipchenko's student Theodosius Dobzhansky in his book Genetics and the Origin of Species (1937).

Use in creationism

In young Earth creationism and baraminology a central tenet is that evolution can explain diversity in a limited number of created kinds which can interbreed (which they call "microevolution") while the formation of new "kinds" (which they call "macroevolution") is impossible. This acceptance of "microevolution" only within a "kind" is also typical of old Earth creationism.

Scientific organizations such as the American Association for the Advancement of Science describe microevolution as small scale change within species, and macroevolution as the formation of new species, but otherwise not being different from microevolution. In macroevolution, an accumulation of microevolutionary changes leads to speciation. The main difference between the two processes is that one occurs within a few generations, whilst the other takes place over thousands of years (i.e. a quantitative difference). Essentially they describe the same process; although evolution beyond the species level results in beginning and ending generations which could not interbreed, the intermediate generations could.

Opponents to creationism argue that changes in the number of chromosomes can be accounted for by intermediate stages in which a single chromosome divides in generational stages, or multiple chromosomes fuse, and cite the chromosome difference between humans and the other great apes as an example. Creationists insist that since the actual divergence between the other great apes and humans was not observed, the evidence is circumstantial.

Describing the fundamental similarity between macro and microevolution in his authoritative textbook "Evolutionary Biology," biologist Douglas Futuyma writes,

One of the most important tenets of the theory forged during the Evolutionary Synthesis of the 1930s and 1940s was that "macroevolutionary" differences among organisms - those that distinguish higher taxa - arise from the accumulation of the same kinds of genetic differences that are found within species. Opponents of this point of view believed that "macroevolution" is qualitatively different from "microevolution" within species, and is based on a totally different kind of genetic and developmental patterning... Genetic studies of species differences have decisively disproved [this] claim. Differences between species in morphology, behavior, and the processes that underlie reproductive isolation all have the same genetic properties as variation within species: they occupy consistent chromosomal positions, they may be polygenic or based on few genes, they may display additive, dominant, or epistatic effects, and they can in some instances be traced to specifiable differences in proteins or DNA nucleotide sequences. The degree of reproductive isolation between populations, whether prezygotic or postzygotic, varies from little or none to complete. Thus, reproductive isolation, like the divergence of any other character, evolves in most cases by the gradual substitution of alleles in populations.

— Douglas Futuyma, "Evolutionary Biology" (1998), pp.477-8

Contrary to the claims of some antievolution proponents, evolution of life forms beyond the species level (i.e. speciation) has indeed been observed and documented by scientists on numerous occasions. In creation science, creationists accepted speciation as occurring within a "created kind" or "baramin", but objected to what they called "third level-macroevolution" of a new genus or higher rank in taxonomy. There is ambiguity in the ideas as to where to draw a line on "species", "created kinds", and what events and lineages fall within the rubric of microevolution or macroevolution.