New Species

The new species changes network structure by adding new sets of interactions, both equally a resources (unless it is a height predator) and every bit a consumer.

From: Advances in Ecological Inquiry , 2017

Cladogenesis

Christopher J. Humphries , in Encyclopedia of Biodiversity (Second Edition), 2001

Anagenesis, Cladogenesis, and Stasis

New species can either become modified through gradual change in an entire lineage in response to a irresolute environs or can emerge through diversification into two or more than species through formation of internal and external isolating mechanisms. Anagenesis is gradual change in an entire lineage ( Figure 1). Division into two or more than species is termed cladogenesis (Figure two). There are many modes of population differentiation and considerable debate as to their roles in speciation. Besides the mechanisms for anagenesis and cladogenesis (speciation) are many and varied. Nevertheless, they all include some course of population differentiation, either by gradual change of genetic differences and natural selection (phyletic gradualism), or by abrupt punctuational changes, involving chromosome inversions or translocations and rapid isolation between populations, or by historical accidents, such as allopatric speciation past vicariance and isolation.

Figure 1. Anagenesis. The transformation of a species or taxon on an unbranched lineage of organisms. Divergence has occurred to such an extent that information technology is justifiably called a new species or taxon.

Figure two. Cladogenesis. The transformation of a species or taxon into two (or more) species (or taxa) past branching along a lineage.

In that location is considerable controversy amongst the theories of diversification and how development proceeds. The Darwinian hypothesis is phyletic gradualism, whereby the same microevolutionary processes that lead to population differentiation cause ever-increasing departure between populations (Figure 3). Eventually, sufficient divergence has occurred for differentiation at species level to be recognized. Differentiation continues at a steady rate and new species originate by dull, gradual changes of ancestral species. The neo-Darwinian perspective is that evolutionary transformation takes place inside species, or lineages, and the branching process of cladogenesis accounts for diversification but relatively small amounts of evolutionary change.

Effigy three. Phyletic gradualism. A fairly constant rate of change through time.

An alternative theory of evolutionary rates and speciation, punctuated equilibrium, was proposed past Eldredge and Gould (1972; Figure 4). Testify from paleontology on well-preserved fossils indicate long periods of stasis, where "species" remain relatively little inverse over long periods of time. At other times at that place appears to have been rapid development and bang-up morphological differentiation. Eldredge and Gould (1972) thus concluded that rates of evolution were not abiding over time. They hypothesized that little evolutionary change occurs within species and that genetic changes within populations do not account for different species. Instead, the events of speciation account for evolutionary change, and curt periods of "punctuation" were interspersed with little of no evolutionary divergence.

Effigy four. Punctuated equilibrium. Morphological stasis of fossil taxa over long periods apparently punctuated with occasional instantaneous change.

Phyletic gradualism and punctuated equilibrium stand for the opposite extremes of a continuum. Recent enquiry, especially on rates of molecular alter, would advise that evolutionary rates are clocklike, or at to the lowest degree "clocky," caused past periods of slow rates of phylesis and rapid periods of cladogenesis. This is reflected in research of the 1980s and 1990s, which has concentrated on uncovering the patterns of divergence through systematic analysis (particularly cladistics). Sustained application of cladistic methods has determined nature's hierarchy and techniques such as maximum likelihood accept been used to appraise rates of change amongst phylogenetic trees.

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Development and Geography

Annalisa Berta , ... Kit M. Kovacs , in Marine Mammals (Third Edition), 2015

half dozen.three Speciation

New species form in three master ways: (ane) allopatric, (2) parapatric, and (iii) sympatric speciation. In the about mutual blazon of speciation, allopatric speciation, new species arise via the geographic isolation of populations (Effigy half dozen.1). In this type of speciation, a physical barrier prevents 2 or more groups from mating with each other regularly, so the independent lineages follow their own evolutionary paths and go increasing different with time. In the instance of marine mammals, isolation might occur through the institution of a barrier such as a warm equatorial water mass dividing a broadly distributed ancestral population of an animal that inhabits cool temperate water. An allopatric origin has been suggested for Pacific white-sided dolphins (Lagenorynchus obliquidens), which inhabit the Northern hemisphere, and its sister species, the dusky dolphin (Lagenorhynchus obscurus), which lives in the southern hemisphere. The two species are separated past warm equatorial water.

Figure six.i. Allopatric speciation in dolphins.

A special version of allopatric speciation is peripatric speciation. It occurs when a small isolated population becomes isolated at the border of a larger, ancestral population (Effigy 6.2). The small population is referred to every bit the founder population. The evolution of the polar comport (Ursus maritimus) from the brown deport (Ursus arctos) is a well-documented example of a living species that gave rising to another living species through the evolution of a population located at the margin of the ancestral species' range (see Chapter 5).

Figure 6.2. Peripatric speciation in polar bears.

In parapatric speciation, a new species arises within a continuously distributed population (Figure 6.3). In that location is no specific physical barrier to factor flow. The population is continuous, but notwithstanding, the population does not mate randomly. Individuals are more likely to mate with their geographic neighbors than with individuals in a different part of the population'south range. A possible example of parapatric speciation in its earliest stages is coastal and offshore populations of bottlenose dolphins, Tursiops truncatus. These dolphin populations are morphologically and, in some cases, genetically singled-out in the 2 different habitat types. The habitats differ in various ways including available prey, with the offshore form feeding on smaller pelagic fish, whereas the littoral grade eats larger, shallow-water fish (Perrin et al. 2011). Over time, these differences might atomic number 82 to sufficient differentiation between these groups that ii species will be recognized.

Figure 6.iii. Parapatric speciation in inshore and offshore dolphins.

In the third major type of speciation, sympatric speciation, a new species arises within the range of the bequeathed population (Figure half-dozen.iv). Like parapatric speciation, sympatric speciation does not require a geographic barrier to reduce gene flow between populations. Instead, exploitation of a different niche, such equally when a population or subpopulation starts feeding on a new prey item, tin can promote reproductive isolation amongst populations. Resident, transient, and offshore killer whales in the N Pacific provide an instance of sympatric speciation having recently taken identify, with connected current and ongoing deviation. Resident populations occur in certain coastal regions and by and large consume fish. Offshore populations inhabit waters farther from the coast and also feed on fish. Transient populations have the largest geographic range, overlapping with the other two types. They feed exclusively on other mammals such as dolphins and seals. Recent genetic information support species status for transients and subspecies designations for resident and offshore populations (Morin et al. 2010). Sympatric speciation is also seen in killer whales from the North Sea (Foote et al. 2011, 2013). Isotopic ratios of prey items spanning over 10,000 years revealed niche variation in killer whales (i.e., herring vs harbor seal specialists) although these ii strategies exhibit some overlap. Proxies for phase of speciation (i.e., lineage sorting of mitogenomes and genotypic clustering) suggest that speciation in N Sea killer whale lineages is at an early phase in the procedure. The chronology of killer whale phylogenetic departure suggests a North Pacific to Northward Atlantic founding issue, followed by a return of killer whales to the N Pacific onetime after.

Figure 6.4. Sympatric speciation in transient, offshore, and resident killer whales.

Another example of sympatry has been described for multispecies fossil seacow (sirenian) communities during the tardily Oligocene (23–26 Ma). The fossil record shows bear witness of morphological differences amid co-occurring (i.e., sympatric) dugongid taxa in unlike ocean basins (Florida, Mexico, and India) suggesting resource sectionalization likely played a role in structuring these communities. For instance, in the Florida aggregation, tusk morphology was the dominant trait for separating feeding preferences. In contrast, in both the Indian and Mexican assemblages, multiple morphological traits (i.east., small body size and strong rostral deflection; the latter an adaptation for bottom feeding in shallower waters) separated co-occurring dugongids (Vélez-Juarbe et al. 2012, Effigy 6.5) (see also Chapter 12).

Figure six.5. Reconstructions of fossil dugongid assemblages from Florida, India, and Mexico during the past ∼26 million years (Vélez-Juarbe et al. 2012).

 Illustrated by Carl Buell.

A fourth mode of speciation, hybridization, entails the successful mating betwixt individuals of two dissimilar species, resulting in offspring that are not sterile. This type of speciation is relatively rare in animals, but information technology is observed ofttimes in plants and is the dominant type of speciation in many agricultural plants (i.e., corn, wheat, oats). Nonetheless, nearly one-half of known marine mammal species take been reported to hybridize either in the wild or in captivity. Virtually crosses accept been described amidst otariid pinnipeds, especially amidst the various southern fur seals (Arctocephalus spp.). The high rate of hybridization has been attributed to population bottlenecks (reduction in population size and loss of genetic variability) resulting from well-nigh decimation of fur seal populations during Antarctic sealing in the 1800s (run into also Chapter 15). The polar carry's genetic history shows that warm periods in the by promoted sometimes extensive crossing with brownish bears (Miller et al. 2012). These two species are isolated when polar bears occupy their normal bounding main ice habitats, but when they are forced to spend more time on land due south of their normal range, the 2 species come into contact and mate. Future hybridization resulting in dilution of the polar bears genome might be i of the many challenges polar bears as a species will face in the coming decades. Natural hybridization leading to speciation was reported for the first time in a marine mammal (Amaral et al. 2014), the Clymene dolphin (Stenella clymene) betwixt 2 other closely related species (Stenella longirostris and Stenella coerueloalba).

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Cladogenesis

Santiago Martín-Bravo , ... Marcial Escudero , in Reference Module in Life Sciences, 2022

The Evolutionary Dynamics of Anagenesis and Cladogenesis: Phyletic Gradualism and Punctuated Equilibrium

New species can either go modified through gradual genetic and/or phenotypic change in an unabridged lineage in response to a changing surroundings or tin emerge through diversification into ii or more than species through the development of reproductive isolation and/or genetic difference. Anagenesis is a gradual change in an entire lineage ( Fig. ane). The sectionalization into two or more independent lineages is termed cladogenesis (Fig. two). There are many modes of population differentiation and considerable argue about their roles in speciation. Besides, the mechanisms for anagenesis and cladogenesis (diversification) vary. Nevertheless, they all include some grade of lineage differentiation, either by (1) phyletic gradualism (Eldredge and Gould, 1972): gradual change of genetic differences (allele frequencies) and natural pick, or (2) punctuated equilibrium (Eldredge and Gould, 1972): long periods of stability interrupted past relatively rapid and abrupt changes, like those involving chromosome duplications (polyploidy) or rearrangements, hybridization or range shifts promoting population isolation, such every bit allopatric speciation past vicariance or dispersal (peripatric speciation).

Fig. 1

Fig. i. Anagenesis. The transformation of a species or taxon on an unbranched lineage of organisms. Eventually, the divergence has occurred to such an extent that it is justifiably called a new species or taxon. Hatch marks represent mutations or phenotypic changes.

Fig. 2

Fig. two. Cladogenesis. The transformation of a species or taxon into 2 (or more than) species (or taxa) by branching along a lineage. Hatch marks represent mutations or phenotypic changes.

There is considerable controversy among the theories of diversification and how evolution proceeds. Darwin's theory of evolution supports phyletic gradualism, whereby the differences within and between populations evolve incrementally, by pocket-size steps at a steady rate (Fig. 3). Eventually, sufficient deviation has occurred to recognize one or more new species, dissimilar from the ancestral species. The neo-Darwinian perspective is that evolutionary transformation takes place inside species, or lineages, and the branching process of cladogenesis accounts for diversification but relatively small-scale amounts of evolutionary change.

Fig. 3

Fig. 3. Phyletic gradualism. A relatively constant rate of change through time. Hatch marks stand for mutations or phenotypic changes. Tip circles represent extinct species and tip squares extant species.

An culling theory of evolutionary rates and speciation, punctuated equilibrium, was proposed by Eldredge and Gould (1972) (Fig. four). Prove from paleontology on well-preserved fossils indicates long periods of stasis, where fossil "species" remain phenotypically relatively little changed over long periods. At other times in that location appears to have been rapid evolution and significant morphological differentiation. Eldredge and Gould (1972) thus concluded that rates of development were not abiding over fourth dimension. They hypothesized that little evolutionary change occurs within species and that genetic changes within populations do not account for different species. Instead, the speciation events account for evolutionary modify, and short periods of "punctuation" were interspersed with petty or no evolutionary deviation.

Fig. 4

Fig. 4. Punctuated equilibrium. Morphological stasis of fossil taxa over long periods punctuated with occasional, relatively fast alter. Hatch marks represent mutations or phenotypic changes. Tip circles represent extinct species and tip squares extant species.

Phyletic gradualism and punctuated equilibrium correspond the opposite extremes of a continuum. There are classic examples inferred from the fossil record for both patterns (encounter MacFadden, 1986) and (Chaline and Laurin, 1986) for phyletic gradualism; (Williamson, 1981) and (Cheetham, 1987) for punctuated equilibrium. On the other manus, the distinction betwixt cladogenesis and anagenesis in the fossil record has been hindered past uncertainty in deviation time estimation, gaps in fossil serial, and difficulties in interpreting biological species from fossil morphospecies (Strotz and Allen, 2013). The punctuated equilibrium hypothesis has been controversial considering character evolution was linked to speciation (Eldredge and Gould, 1972). However, there is ample evidence that evolutionary change does not necessarily entail speciation (Futuyma, 2013). A combined model was proposed past Malmgrem et al. (1983), called "punctuated gradualism", in which both slow, gradual and fast, abrupt changes may take place, but speciation does non necessarily have to occur during periods of change (Fig. five).

Fig. 5

Fig. v. A. The Cladogenetic State Speciation and Extinction model (ClaSSE). All 10 model parameters implemented in ClaSSE are represented, including extinctions (µ), anagenetic (q) and cladogenetic changes (λ). 0, ancestral state (white); 1, derived country (black). For example, µ0 would be the extinction rate of state 0; q01, the anagenetic modify rate from state 0to state 1 ; λ001, the cladogenetic change rate from country 0 to two descendant states 0 and ane. B. Phenotypic changes by gradualism (B1) and punctuated equilibrium (B2) implemented in the ClaSSE model.

 Reproduced from Couvreur, T.50.P., Kissling, W.D., Condamine, F.Fifty., et al., 2014. Global diversification of a tropical constitute growth form: Ecology correlates and historical contingencies in climbing palms. Frontiers in Genetics v, 452.

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Grains Other Than Cereals, Non-Starch Polysaccharides

L. Ramsden , in Reference Module in Food Science, 2016

Identifying NSPs

Every bit new species are tested for potential as grain producers, investigation for the presence of NSPs should exist a component in any study. It is relatively unproblematic to define the presence of any unusual polysaccharides where these comprise unlike sugar units from those in known polymers. From the analysis of the monosaccharide composition of a grain sample after total acrid hydrolysis, information technology will ofttimes be possible to infer the presence of polysaccharides from the ratios and quantities of monosaccharides present. Monosaccharide assay is conducted past HPLC or gas chromatography later generation of volatile sugar derivatives. Where the polysaccharides differ more subtly by variation in the linkages between similar monosaccharides than the method of choice is usually methylation analysis, requiring the production of methylated sugar derivatives reflecting the positions of glycosidic linkages that can so exist analyzed by GC/MS. Where soluble polysaccharides are under investigation clear signals reflecting the position of linkages tin sometimes be obtained relatively chop-chop past NMR analysis.

The aforementioned analytic techniques will usually be complemented by prior separation of polysaccharides present into different fractions depending on their solubility in different solvents. Using the water solubility/insolubility of a polysaccharide is a rapid way to simultaneously excerpt polysaccharides from a sample and distinguish among those present in the grain.

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Sea Plants

Romain Gastineau , ... Jean-Luc Mouget , in Advances in Botanical Research, 2014

15.11 Conclusions

To place new species, especially in diatoms, one should rely on the decisive combination of traditional morphological traits, molecular barcoding using several genes, and data retrieved from reproductive biology. Nevertheless, it is often hard to perform a congruent diagnosis or identification of a new strain, when only one clone is available. The present review illustrates how this difficulty can be overcome. Morphological differences in the density of striae, although pocket-size, were founded to be statistically pregnant (Student's test) from those displayed by various populations of H. ostrearia. However, peculiarly because only i Australian strain of H. ostrearia has been isolated and studied, this information lonely is bereft to conclude whether this is a new species, a subpopulation or just an atypical strain of H. ostrearia. Geographical separation usually calls for a college degree of departure, but this does not apply to the blue diatoms collected in Narragansett Bay (Rhode Island, United states of americaA.), which were identical under all aspects, including molecular, to the H. ostrearia collected in the French Atlantic declension. This suggests a recent transfer of species, which could take occurred during the early twentieth century, when oysters were brought from France to the Usa. Like transportation could have previously happened in Commonwealth of australia, but the chief mechanism by which alien species are introduced is more than probable recent release of ship water ballasts, which is a real ecology outcome (Gregg, Rigby, & Hallegraeff, 2009).

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Volume 1

Cletus P. Kurtzman , ... Teun Boekhout , in The Yeasts (Fifth Edition), 2011

2.i Description of New Taxa

2.1.one Species

Publication of new species must include a clarification of essential characters besides as a diagnosis that distinguishes the taxon from previously described species. Since January 1, 1935, the clarification and/or diagnosis must be given in Latin. Failure to comply with this requirement results in an invalidly described species termed a nomen invalidum (nom. inval.). A nomen invalidum also results if publication is non in a recognized scientific journal, east.yard., as in a patent or a merchandise magazine. If the new species is designated without a description or a diagnosis, it is invalid and termed a nomen nudum (nom. nud.). Names of taxa must be given in Latin or modified in such a way that they follow the rules of Latin derivation including appropriate gender designations. If a name has been incorrectly crafted, it may be treated every bit an "orthographic error" and corrected. An example is Pichia membranifaciens for which the 1888 spelling "membranaefaciens" has been corrected. The say-so name does not change due to the spelling correction. Other requirements for valid publication include deposition of blazon material in a publicly accessible herbarium. This material must be an original specimen of the organism, and it is to be dead and dried. The 1994 Code (Greuter et al. 1994) changed the requirements to permit lyophilized specimens to be valid type cloth (holotype) and that living cultures derived from the lyophilized fabric are considered ex typo, i.e., from the type. It seems that once the original fabric is wearied, there is no longer type material available. A possible solution to this trouble would be to lyophilize new material and designate it equally a neotype, a convention permitted when the original type material is lost or destroyed and the species can be otherwise recognized. This discussion leads to the recognition that a majority of shortly accustomed yeast species are technically invalid considering legitimate blazon cloth has not been preserved. A portion of presently lyophilized stocks of the holotype that are maintained in culture collections should be withheld from distribution and designated equally type. Consequently, the designation of "Type strain" given for each cultivatable species described in this volume tin, at best, correspond an ex-type. The 1994 Code recognized the need for living cultures in the practice of modern taxonomy and stated in Recommendation 8B.1:

"Whenever practicable a living culture should exist prepared from the holotype cloth of the proper noun of a newly described taxon of fungi or algae and deposited in at least two institutional culture or genetic resource collections. (Such activeness does not obviate the requirement for a holotype specimen under Art eight.2)."

The 1994 Lawmaking further states in Recommendation 8B.two:

"In cases where the nomenclatural blazon is a culture permanently preserved in a metabolically inactive state (meet Art. viii Ex. one), any living isolates obtained from that should exist referred to as 'ex-type' (ex typo), 'ex-holotype' (ex holotypo), 'ex-isotype' (ex isotypo), etc., in order to make it clear they are derived from the type but are non themselves the nomenclatural type."

From these recommendations, it is clear that the Lawmaking strongly encourages scientific cooperation and communication through active sharing of published taxonomic specimens. A listing of commonly used yeast culture collections is given in Chapter seven.

From gene sequence comparisons, strains that stand for new species are normally hands recognized (Chapter ten). Still, some would argue confronting clarification of a new species based on a single strain. The argument is that a single strain does non reverberate the genetic variation that might be constitute in a species, and that little can exist learned of the environmental of a species when only a single strain is available. However, nearly one-third of described yeast species are based on a single strain. If these species had not been described, much less would be known virtually the phylogenetic diversity of the yeasts. From the perspective of understanding diversity amid the yeasts, description of single-strain species is to exist supported, although descriptions based on multiple strains are preferred. Further, it is recommended that the description should exist based on multigene assay to lessen the possibility that the strain represents a hybrid of known species.

2.1.2 Genera, Families, Orders

The rules for describing new genera, families and orders are like to those for describing new species. The taxa must be based on a validly described species and provided with a Latin description and diagnosis. The rules of priority are briefly described below, just ane exception is that orders are exempt from priority usage.

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Research methods for entomopathogenic microsporidia and other protists

Leellen F. Solter , ... Jiri Vávra , in Transmission of Techniques in Invertebrate Pathology (Second Edition), 2012

2 Deposition of reference slides and alive type cloth

When a new species is described, a type specimen should be deposited with the International Protozoan Blazon Collection at the National Museum of Natural History of the Smithsonian Institution or other repository. Correspondence should be addressed to: Museum Specialist, Section of Invertebrate Zoology, Smithsonian Institution Museum Support Center, MRC 534, 4210 Silver Hill Road, Suitland, Medico 20746-2863, United states of america. A deed of gift form must be submitted with the type slides (information can be institute at http://invertebrates.si.edu/donation.htm).

The cloth must be permanently mounted on glass microscope slides and affixed with labels listing genus, species, writer, and yr; material type (paratype, lectotype, etc.); collection locality; genus, species, and class of the host. Slides must exist arranged in order and be accompanied past a list of this information: stain, collector, number of specimens, original field number, identifier, pertinent remarks, and higher classification. A brusque letter of the alphabet should exist sent with the specimens stating that they are being donated. Moisture specimens (specimens in alcohol or formalin) must comprise labels with the aforementioned data (except stain) or exist accompanied by inquiry papers containing this information.

Blazon material (specimens from which a new species was described) will form a separate collection and must be accompanied by split up data sheets. The descriptive paper of a blazon material must be accustomed for publication or be in press before type specimens are submitted to the museum. At to the lowest degree one copy of each publication should exist supplied for the museum's library.

The museum affixes an accession number to each slide and all pertinent papers tin be located past this number at any time. All cloth is assigned a itemize number in addition to the accession number. Slides are stored numerically past itemize number. Wet specimens accept a special department in the collection area. Slides requiring itemize numbers for forthcoming publications are speedily accommodated. Collections are loaned in full or in part to investigators or institutions; the duration of the loan being arrived at past negotiation, but not to exceed ane year. Loans are renewable annually upon request with justification. Utmost care of materials loaned is causeless.

Viable spore samples may be of interest to the American Type Culture Drove (ATCC), Protistology Drove, 10801 Academy Boulevard, Manassas, Virginia, VA 20110-2209, USA. Contact a collections specialist to determine the requirements to annal live cultures (http://www.atcc.org/EmailaCollectionScientist/tabid/722/Default.aspx).

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Biodiversity, Development and

Gregg Hartvigsen , in Encyclopedia of Biodiversity, 2001

V.B. The Big Question: How Will the Procedure of Development Influence Biodiversity Dynamics?

Evolution generates new species in the backwash of mass extinction. This is well supported by the fossil record and appears, in geological fourth dimension, to be rapid. The current extinction event taking place on Globe, even so, appears to be more rapid than has occurred previously. Speciation will undoubtedly pb to the ascension of new taxa simply over time scales that are probable to exist too long to have a noticeable effect in our lifetime.

The other part that evolution plays in biodiversity is its ability to influence the stability of communities. Little is known near this function of evolution. Empirical data for plant communities suggest that stability is correlated with biodiversity, such that more diverse communities are more resilient to disturbance. Natural communities are oft equanimous of genetically variable individuals, which provide the foundation that enables species to evolve in response to biotic and abiotic factors over time. Also, communities with more species are in full general more diverse genetically. If the time frame of environmental change tin be matched by choice operating on genetic diverseness, communities may resist disturbances past adjusting to changes over fourth dimension. The illustration of species wandering over an "adaptive landscape" (sensu Sewall Wright) produces an image of communities functioning as complex adaptive systems. Ecosystems that part as complex adaptive systems may resist ecology fluctuations. If, notwithstanding, environmental disturbances are abrupt, communities may either not be able to react quickly plenty or suffer overloads that essentially shake species out of the customs. In that location is show that communities harbor redundancy at the species level, but we have not nonetheless adamant patterns that identify which species are necessarily of import or unimportant to community function. Therefore, the loss of species from communities is likely to subtract, if only slowly, the stability of communities.

Theoretical work suggests that the process of development may increase the resilience of communities to disturbance. This area of inquiry is in its infancy and will probable become an of import and quickly developed subject in the following decades.

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