Origin Of Species Research Articles

Factors for Manipulating the Tolerance of the Search Method Used in Genetic Algorithms to Determine Nanoclusters

Objective: The objective is to present a new method to explore BFGS where a new decision-making flow was added in order to optimize and computationally improve the performance of the Genetic Algorithm, controlling the value of the gradient as it evolves. Theoretical Framework: In the literature, the work presented by [Chen, 2014] stands out, who proposed that there must be a repulsive contribution to ensure the stability of the structure, which is introduced as the interaction between atomic pairs that makes up the second term of the cohesion energy. [Goldberg,1989] proposed the use of a genetic algorithm to search for available minima in the potential energy function associated with clusters. Method: The methodology adopted in this research was the use of Evolutionary Algorithms (EAs) are inspired by the principle of natural selection and survival of the fittest individuals, discovered by physiologist Charles Darwin and described in his book "The Origin of Species", from 1859. Among various selection methods, the roulette wheel method was used, as it is useful in problems where diversity needs to be maintained to avoid premature convergence. The crossover used by Deaven and Ho, which is a technique known as the cut-and-splice method, applied in the context of optimizing molecular structures or atomic clusters and the aluminum and magnesium clusters that were explored using a Genetic algorithm applied to Gupta potential function and tuned to look for the lowest energy minima for each cluster size. Results and Discussion: The results obtained revealed [synthesize the main results of the research]. In the discussion section, these results are contextualized in light of the theoretical framework, highlighting the implications and relationships identified. Possible discrepancies and limitations of the study are also considered in this section. Research Implications: The objective of this article was to present a new method to explore BFGS where a new decision-making flow was added in order to optimize and computationally improve the performance of the Genetic Algorithm, controlling the value of the gradient as it evolves. This new method proved to be very promising according to the results presented in the previous section, since the Sequential Genetic Algorithm, which becomes quite costly as it invokes the BFGS optimization method, always has a very small Gradient vector error, unlike the Genetic Algorithm which It starts with a very low value and is gradually increased according to established criteria. In experiments carried out with both 10 seeds and 30 seeds, the Genetic Algorithm obtained better energies in the general average and the standard deviation was also much better, reaching better global minimums. Originality/Value: This study contributes to the literature by creating new flows in the Genetic Algorithm, enabling computational gains in the processing of experiments, which was proven in the results obtained.

Classification and Characterization of Anthropogenic Plant Communities in the Northwestern Iberian Peninsula

ABSTRACTQuestionsCan we reconcile regional and European classifications of anthropogenic plant communities at the biogeographical scale? How are these communities characterized by species origins, traits and ecological preferences?LocationAtlantic territories in the NW Iberian Peninsula (a.k.a. Cantabrian Mixed Forests ecoregion); south‐western Europe.MethodsWe classified 2508 plots with the aim of being consistent with regional phytosociological expertise, while matching that expertise with current EuroVegChecklist alliances. We used modified TWINSPAN to revise the original phytosociological classification, followed by semi‐supervised re‐classification of the whole dataset. We determined the proportion of natives, archaeophytes, and neophytes. We also described the alliances in terms of species traits (lifeforms, height, and flowering phenology) and ecological requirements (temperature, moisture, light, nutrients, soil reaction, disturbance frequency, and severity).ResultsWe assigned 2086 vegetation plots to 25 anthropogenic alliances representing nine vegetation classes (Cymbalario‐Parietarietea diffusae, Polygono‐Poetea annuae, Papaveretea rhoeadis, Digitario sanguinalis‐Eragrostietea minoris, Chenopodietea, Sisymbrietea, Bidentetea, Artemisietea vulgaris, and Epilobietea angustifolii). The plots included 1149 species: 78% natives, 15% archaeophytes and 7% neophytes. Vegetation groups were organized along a principal axis of abiotic stress (dry‐sunny to moist‐shady habitats) and a secondary axis of disturbance.ConclusionsIn the Iberian Atlantic territories, anthropogenic habitats host one third of the regional plant species pool and one fifth of the Iberian flora. Mesic perennial ruderal vegetation is especially rich in native species and can be a biodiversity asset in urban landscapes. Our biogeographical‐level synthesis can improve the management of anthropogenic plant communities and contribute towards a European‐level synthesis of human‐made vegetation.

Discovery of gallic acid-based mitochondriotropic antioxidant attenuates LPS-induced neuroinflammation.

Mitochondria are complex organelle that plays a pivotal role in energy metabolism, regulation of stress responses, and also serve as a major hub for biosynthetic processes. In addition to their well-established function in cellular energetics, it also serves as the primary site for the origin of intracellular reactive oxygen species (ROS), which function as signaling molecules and can lead to oxidative stress when generated in excess. Moreover, mitochondrial dysfunction is one of the leading cause of neuroinflammation. In this regard, we have rationally designed a triazine derived mitochondriotropic antioxidants (Mito-TBA), based on gallic acid and triphenylphosphonium (TPP) cation to specifically target mitochondria to mitigate neuroinflammation. In vitro Mito-TBA-3 inhibits mitoautophagy, offers neuroprotection by inhibiting the LPS induced TLR-4 activation and activating the Nrf-2/ARE pathway in PC-12 derived neurons. In vivo Mito-TBA-3 rescue memory deficit, reversed depression like behavior, inhibited neuroinflammation, and decreased proinflammatory cytokines in LPS induced neuroinflammation rat model. Overall, based on biophysical, in vitro and in vivo analysis, Mito-TBA-3 offers valuable insights as a potent therapeutic lead molecule to combat neurodegeneration even outperforming a well-known non-steroidal anti-inflammatory drug (Aspirin), it also has the potential to use as a promising therapeutic candidate for other mitochondrial oxidative stress related disorders.

Decoupling the Effects of Fire and Dry Season Drought on Seedling Establishment Success of Tree Functional Types in Humid Savannas

Background: In the seasonal tropics, fire generally occurs in the dry season. Consequently, the effects of fire and dry season drought on seedling establishment of different tree functional types are correlated. Therefore, factors that are more important for tree recruitment in forest-savanna ecotones are still poorly understood. Methods: We studied seedling establishment success of seven tropical tree species (of forest and forest-savanna transition origins) in a common garden experiment using combinations of dry season (irrigation vs no-irrigation) and fire (burning vs no-burning). Results: We found that burning caused a significant decline in survival of forest species, but not of forest-savanna transition species. The combination of burning without dry season irrigation (which typifies dry season fire) had the largest overall effect on survival, mass and height of plants. The separate effect of burning was larger than that of dry season drought. Seedling size at the onset of the dry season significantly predicted root starch content and, hence, dry season survival probability of forest-savanna transition species, but not of forest species. Dry season irrigation increased post-fire survival of forest-savanna transition species, but not of forest species, possibly linked to differences in resprout capacity and root starch reserves. Conclusion: Our work shows that fire and dry season drought produce a stronger negative effect together, than their separate effects on seedling establishment particularly of forest species. This provides a mechanistic explanation for the existence of forest-savanna transition species in fire-prone humid savannas. Implications for Conservation: The mosaic of forest, transitional and savanna vegetation within the forest-savanna ecotone reflects the influences of fire and dry season drought. Any changes in these elements will influence vegetation dynamics within the forest-savanna ecotone.

Speciation studies in the genomic era.

Since Darwin's era, speciation has been one of the most central issues in evolutionary biology studies. Understanding the processes of species origin is crucial in deepening our understanding of the formation of species biodiversity, which is essential for their protections. However, speciation research has been challenging due to the rather complex evolutionary histories of many extant species. In recent years, with the continuous advancements in genomic sequencing techniques, significant advances have been achieved in the field of speciation researches. In this review, we overview speciation study advances, especially in the concepts and latest developments in research methods for studying speciation in the genomic era, encompassing the major research aspects: species delimitation, bifurcating speciation, hybrid speciation, polyploid speciation, reproductive isolation genes and speciation genes. Furthermore, we discuss the limitations of these studies and methods. Finally, we provide the outlook on the future challenges and directions in speciation researches.

Ballast operations at ports: Nemrut Bay analysis

Ballast water operations are one of the most essential activities of commercial ships whose purpose of existence is to carry cargo between ports. With their growing ballast capacities, ships become an important vector that carries the origin species of the sea waters they took into their ballast tanks. Foreign species were transported between ports with ballast water in these operations, which have been going on since the mid-1800s. Although various guidelines were published by the International Maritime Organization (IMO) regarding ballast water, whose adverse effects on the marine environment began to be noticed in the international arena in the late 1980s, the desired positive effect could not be achieved. As a result of technological developments and R&D studies, ballast water treatment systems (D-2 Standard), which have completed the type approval process, have started to be applied on ships. The deadline for applying treatment systems, which have various types in terms of method and capacity, on ships is September 8, 2024. In this study, an application was made on ships calling Aliağa Port Nemrut Bay to investigate compliance with the International Ballast Water Management Convention and ship ballast operations’ by port state control measures. This study showed that most ballast water at Aliağa Port (73%) was treated and discharged. Mechanical filter + UV treatment systems are also the preferred type (63%) among other systems. Also, according to this study's data set, the Adriatic Sea is the majority (44%) among other origins for Aliağa Port.

Development of Genomic SSR Markers for Assessing Genetic Diversity in Korean Native Fallopia multiflora

Fallopia multiflora, a perennial herb in the Polygonaceae family belonging to the genus Fallopia Adanson, is traditionally used as a Chinese herbal medicine. However, there is still confusion about the botanical origin of the species and the phylogenetic relationship between the cultivars and the wild relatives. To develop an efficient identification method, a molecular analysis was performed using SSR markers. The genetic diversity of the F. multiflora genetic resources has been assessed by using 10 locally collected accessions, including varieties and landraces. We screened 100 pairs of SSR primers and selected 71 successfully amplified SSR markers, in which one SSR was found to be a monomorphic marker. The results indicated that the number of alleles (NA) ranged from 2 to 10, with an average of 4.1 alleles. The major allele frequency (MAF) spanned from 0.20 to 0.90, the observed heterozygosity (HO) ranged from 0 to 0.80, and the polymorphic information content (PIC) varied between 0.16 and 0.86. Clustering analysis using an unweighted pair group mean algorithm (UPGMA) with all 70 SSR markers revealed three clusters among the F. multiflora accessions. Furthermore, seven minimum marker set combinations were identified and proved useful for variety identification. Therefore, these SSR markers could be valuable for various applications, including cultivar identification and assessing the purity of F. multiflora populations. Three genetic groups of F. multiflora should be considered as independent units for conservation and germplasm management of the species.

Unraveling the neural basis of behavioral isolation through the lens of audition in anurans.

Background The origin and maintenance of species is a unifying theme in evolutionary biology. Mate choice and selection on sexual signals have emerged as powerful drivers of reproductive isolation-the key pillar of the Biological Species Concept. The mechanistic underpinnings of isolating behaviors lie in the circuit- and cellular-level properties of the brain and yet remain relatively understudied. Summary Here, I argue that temporal auditory selectivity in anuran amphibians offers a window into the proximate mechanisms of reproductive isolation. First, I discuss anuran behaviors as a longstanding neuroethological model with which to examine behavioral reproductive isolation and its neural correlates. Next, I review how modern neurobiological techniques are revealing the proximate mechanisms of the evolution of divergent mate preferences in anurans, highlighting cellular-level neural shifts in temporal coding. Finally, I discuss future research directions to reveal the neural mechanisms through which behavioral isolation is generated and maintained in anuran model systems. Key messages Anurans offer a powerful model for addressing questions about how neural barriers to gene flow arise across biological scales, and how changes in the brain contribute to speciation. Modern evolutionary neurobiology will benefit from applying new tools to this longstanding neuroethological model clade.

Ancient gene introgression promotes biodiversity of Nymphaea nouchali in Hainan under environmental changes

AbstractHybridization is common in the plant kingdom. Under the influence of global climate change, an increasing number of hybrid species have experienced significant shifts from the geographical distribution of their parents, making it more difficult to detect ancient gene flows. Nymphaea nouchali is a rare aquatic flower native to Hainan Province. Owing to habitat destruction and human interference, the natural range of N. nouchali has gradually reduced to the point of extinction. To explore how hybrid populations form using RAD‐seq with population genetic analysis, it is shown that there are heterozygous deletions and inbreeding in N. nouchali and a number of ancestral components in Nymphaea lotus, low of genetic differentiation, and little gene flow between N. nouchali and N. lotus, and ancient introgression between ancestors may have been more frequent than gene exchange after the origin of the species. Accordingly, the ancient N. nouchali genotypes were gradually infiltrated by N. lotus genes and their forms changed in Hainan. Potential distribution pattern analysis also predicted the possible distribution of N. lotus in Hainan. This lays a foundation for exploring the natural genetic mechanisms of Nymphaea species formation and evolution.

Long‐term stability of tropical forest metacommunities in Puerto Rico: Native and non‐native species

AbstractAnthropogenic disturbances alter trajectories of ecological succession, introduce spatiotemporal variability in the composition of communities, and potentially create communities that differ substantially from those prior to disturbance. Invasive species are introduced or spread by human activities, with considerable effect on native ecosystems throughout the world. We evaluate the temporal stability of woody plant metacommunity structures and the mechanisms that give rise to them in a tropical disturbance‐mediated environment. We used data collected over 20 years to (1) evaluate elements of metacommunity structure, (2) identify the gradients along which metacommunities are structured, and (3) quantify the relative contributions of environmental and spatial factors on variation in species composition. Analyses were conducted separately for combinations of life zone (areas defined by edaphic features and climate) and species origin (native versus non‐native). Native species exhibited compartmentalized structures (i.e., groups of species with similar distributions that are replaced by other such groups along a gradient), whereas non‐natives exhibited random structures. Metacommunities based on all species were consistently compartmentalized, except in dry forest, which exhibited random structure. Compartmentalized structures occurred along gradients defined by life zone and soil type, whereas no environmental factors were consistently associated with random structures. Metacommunity structure was stable through time despite a complex disturbance regime. Dry forests, which have experienced the most extensive and intensive history of anthropogenic disturbances of any life zone on Puerto Rico are characterized by degraded and fragmented landscapes, with species that do not respond to a common environmental gradient.

Recent Origin of a Range-Restricted Species With Subsequent Introgression in its Widespread Congener in the Phyteuma spicatum Group (Campanulaceae).

Understanding the causes of restricted geographic distributions is of major interest to evolutionary and conservation biologists. Inferring historical factors has often relied on ad hoc interpretations of genetic data, and hypothesis testing within a statistical framework under different demographic scenarios remains underutilised. Using coalescent modelling on RAD-sequencing data, we (i) test hypotheses about the origin of Phyteuma gallicum (Campanulaceae), a range-restricted endemic of central France sympatric with its widespread congener Ph. spicatum, and (ii) date its origin, irrespective of its mode of origin, to test the hypothesis that the restricted range is due to a recent time of origin. The best supported model of origin is one of a dichotomous split of Ph. gallicum, confirmed as distinct species, and the Central European Ph. nigrum with subsequent gene flow between Ph. gallicum and Ph. spicatum. The split of Ph. gallicum and Ph. nigrum is estimated at 45-55,000 years ago. Coalescent modelling on genomic data not only clarified the mode of origin (dichotomous speciation instead of a previously hypothesised hybridogenic origin) but also identified recency of speciation as a sufficient, although likely not the sole, factor to explain the restricted distribution range. Coalescent modelling strongly improves our understanding of the evolution of range-restricted species that are frequently of conservation concern, as is the case for Ph. gallicum.

Key stage of evolution of endemism in Gaoligong Shan after the late Pliocene

AbstractIn the Mountains of Southwest China (MSC), accelerated diversification triggered by mountain uplift and monsoon intensification in the Miocene is widely revealed, but less is known about the stage after the Pliocene. Thus, the tempo‐spatial evolution of the endemism of Gaoligong Shan (GLGS), a young and isolated mountain with the highest biodiversity in the MSC, was determined. Temporal patterns were inferred by the stem ages of the endemic species and spatial patterns were inferred through ancestral area reconstructions and the distributions of the sister taxa. Temporally, the calibrated origin times of 114 phylogenetically well resolved endemic species (75 plants, 33 animals and six fungi) ranged from the early Miocene to the Holecene. Spatially, 82 centric origin species (mean = 3.08 Ma) were significantly younger than 32 eccentric origin species (6.84 Ma). Eccentric origins accumulated smoothly while centric origins burst after the late Pliocene, especially after the Pleistocene (n = 52). In centric origins, most of the sister taxa showed sympatric (n = 47) or allopatric (n = 23) distributions in the GLGS. The eccentric origins were mainly dispersed from the southern lower latitude region (n = 20). Principle component analysis indicated that niche conservatism exerted greater contribution to the speciation of the endemic species. Uplift of the GLGS and monsoon intensification during the late Pliocene accelerated the formation of its endemism. The “Species pump” effect of the Pleistocene climatic fluctuations is further revealed. Speciation triggered by geological isolation by mountain and river barriers through niche conservatism exceeds adaptive evolution.

Origins

Abstract Scientific origins are information sources that transmit encoded information signals to receivers. Originary sciences identify information preserving receivers and decode the signals to infer their origins. Paradigmatic cases of scientific origination such as the Big Bang, the origins of species, horizontal gene transfer, the origin of the Polynesian potato, and ideational origins in the history of ideas are analyzed to discover what is common to them ontologically and epistemically. Some causes are not origins. Origination supervenes on causation, but has different properties. The unique properties of origins that causes do not share shield theories of origination from the kind of counterexamples and counterintuitive results that challenge comparable theories of causation. The epistemology of origination may serve as a basis for founding a novel epistemic and methodological division of the sciences into originary historical sciences and causal theoretical sciences.

Differences in phenology between non‐native C4 grasses and native C3 and C4 grasses in a seasonally dry ecosystem

AbstractPlant species phenology is an important driver of invasions in seasonal climates. The phenology of non‐natives is generally uncoupled from that of native species. Grasses cover a large proportion of the land surface and are important invaders around the world. Interestingly, the phenology of native and non‐native grasses could be modulated by the different metabolic pathways. We aimed to compare the vegetative and reproductive phenology of invasive C₄ grasses with that of coexisting native C₃ and C₄ grasses and to explore the relationship between phenology and climate. We recorded the onset, duration and synchronicity of vegetative and reproductive phenology (flowering and fruiting) during 1 year. Native C₃ grasses had 50% of their above‐ground biomass green earlier and remained in that state for a longer period than non‐native and native C₄ grasses. Flowering and fruiting occurred earlier in non‐native C₄ grasses than in native C₄ grasses. The flowering period was longer in non‐native C₄ than in native C₃ and C₄, with the non‐native Melinis repens (Poaceae), a highly invasive species worldwide, accounting for most of the difference. Non‐native C₄ tended to exhibit a lower flowering and fruiting synchrony than both native C₃ and C₄ species. Finally, reproductive and vegetative phenology was positively associated with temperature, while precipitation was mostly associated with C₄ species. The uncoupled vegetative phenology observed could be related to differences in metabolism among the studied species, while the uncoupled reproduction between non‐native and native C₄ grasses could be due to an advantage in resource use by non‐native species. Our work provides the first insight into the possible role of the species origin and metabolic pathways in the vegetative and reproductive phenology of invasive non‐native C₄ and native C₃ and C₄ grasses. Finally, we suggest future directions to elucidate these processes.

Evolution: Morphological complexity fuels rapid species turnover.

Some animal lineages, such as mammals or trilobites, show particularly high rates of evolution- that is, of species origination and extinction. What makes such lineages special is not clear. A new study shows that, in fossil ammonoid cephalopods, more complex shell ornaments are associated with higher evolutionary rates.

Comparative karyotype analysis provides cytogenetic evidence for the origin of sweetpotato.

The origin of hexaploid sweetpotato [Ipomoea batatas (L.) Lam.] remains controversial. Comparative karyotype analysis is particularly useful in determining species relationships and the origin of polyploid species. In previous study, we developed a set of oligo probes and identified all chromosomes of Ipomoea nil, a model diploid Ipomoea species. Here, we found that this set of oligo probes could be used to identify all chromosomes of sweetpotato and its wild relatives with different ploidy. Karyotypes based on individually identified chromosomes were established and the number and position of 5S and 35S rDNA loci were determined for these Ipomoea species. Comparison of their karyotypes revealed distinct variations in the karyotypic parameters. Karyological relationships among these species were revealed by principal coordinate analysis (PCoA) based on six quantitative parameters (x, 2n, TCL, MCA, CVCL and CVCI). These results show that I. trifida is the most closely related diploid species to sweetpotato, and other diploid species could be excluded from consideration as its possible diploid ancestor. In addition, our study also provides cytogenetic evidence for the segmental allopolyploid hypothesis of sweetpotato origin.

Recruitment of chromatin remodelers by XIST B-repeat region is variably dependent on HNRNPK.

X-chromosome inactivation is triggered by the long non-coding RNA XIST, whose structure is characterized by tandem repeats that modularly recruit different proteins and chromatin remodelers. Previously, we reported that the addition of the mouse PID region to a transgene with human repeat regions A, F and E (miniXIST; 5.1kb) enabled binding of HNRNPK and also enabled the induction of silencing and recruitment of H3K27me3, UbH2A and H4K20me1, but only partially. As the 680bp PID region enabled so many features of inactivation, we hypothesized that augmenting the PID with more mouse or human sequences rich in CCC motifs would allow us to design a short transgene which was as effective as Full XIST. Three new transgenes using the A, F and E human domains as a backbone were tested for ability to induce silencing and heterochromatic mark recruitment. The all human-derived BhB-BhB transgene (4.9kb) was as good as our previous miniXIST, suggesting that these domains are the human equivalent of the mouse PID region. A PID-PID transgene (5.8kb) was not statistically different from Full XIST and could be potentially used for chromosome therapy. Adding BhB to PID (BhB-PID, 5.4kb) had an intermediate efficacy compared to the other two transgenes, suggesting that the most important component for silencing and heterochromatic mark recruitment is the number of CCC motifs, not the species of origin. Finally, we created a heterozygous HNRNPK deletion and observed a disproportionate impact on HNRNPK and UbH2A recruitment to XIST, reflecting complex roles for the PID and HNRNPK in X-chromosome inactivation.

Species delimitation and historical biogeography of Sturisoma Swainson, 1838 (Loricariidae: Loricariinae): Hidden diversity along the Amazon River

In the present study, we used DNA sequences from three mitochondrial (COI, Cytb, and nd2) and one nuclear (RAG2) marker, to perform species delimitation analyses (ABGD, GMYC, BPP, and bPTP) within Sturisoma to test the validity of currently recognized and potential new species for the genus. Additionally, a historical biogeographic analysis was carried out to test the age and centers of origin for species of the genus. Results found here indicate a high degree of genetic divergence with overlapping morphological characteristics suggesting a greater diversity than previously proposed for the genus. All valid species currently included in Sturisoma were confirmed here, and one potentially undescribed species was recovered. Based on genetic distances, geographical patterns and historical biogeography, the diversification of the group could be related to dispersal events from Western to Eastern Amazonia resulting in sympatric species that are highly divergent genetically but conservative morphologically. The lower (eastern) Amazonas and the Orinoco River basins were identified as the main centers of origin for the genus, with an approximate age of origin of 13 Mya, during the Miocene. The diversity of the genus is likely to be even higher because the Amazon River is a hotspot of hidden biodiversity.

Development of Electrochemical Sensors for Dissolved Inorganic Nitrogen Detection at Release Sites into the Great Barrier Reef

The accumulation of dissolved inorganic nitrogen (DIN); nitrate, nitrite and ammonium species of anthropogenic origin within water bodies remains a key environmental challenge. It causes detrimental effects to aquatic ecosystems and human health. Regular monitoring of nutrient levels in vulnerable sites is therefore the first crucial step in managing water quality. Sensor technologies that work in real time, on-site, reliably and frequently with immediate data-transfer to end-users are necessary for effective monitoring. One ideal detection system is based on electrochemical sensors. To this end, a low-cost, easy-to-use DIN sensor device was developed using modified screen-printed electrodes. Sample delivery and extrication was possible via an automated Arduino-pump attachment, with scheduled readings and imbedded algorithms for data processing. Additionally, data captured by the sensor was capable of being wirelessly transferred to a separate CPU unit. The screen-printed electrodes were immobilized with nanomaterials specific to the target analyte, and the solid-state reference electrodes were also modified to compensate for matrix effects, particularly from chloride. Nitrate and ammonia electrodes were based on ion-selective membranes; nitrate ionophores and nonactin respectively. Nitrite electrodes were immobilized with gold nanoparticles, nickel oxide nanoparticles, and electrochemically deposited with reduced graphene oxide. To determine operational success in the field, the automated sensor systems were tested on water samples from waterways draining into the Great Barrier Reef. Inter-laboratory comparisons were undertaken for quality control. This research exhibits promising applications for more affordable, miniaturized, real-time field sensors with strong potential for improving water quality and management.

Classes as Clusters

This essay examines Charles S. Pierce’s critique of nominalism against the background of the debate about natural kinds at the time of the first reception of Darwin's Origin of Species. In the history of the so-called dispute over universals in Western philosophy, the phenomenon of species constancy has always been of central importance (since Plato). Darwin's historicization of species was seen by some of Peirce's contemporaries, including Chauncey Wright, as support for Mill's nominalism. Peirce believed the opposite, that Darwin's history of the origin of species supports realism about universals. This is so because for Darwin species arise independently of the human mind. Just as a history of science does not have to cast doubt on the reality of scientific disciplines, a history of species does not have to make their reality appear questionable. However, a concept of modifiable species is needed to understand this history. Peirce develops such a concept by understanding species, ahead of his time, as variable clusters.