Both autochthonous and introduced fruit crops exploitation in Venezuela have suffered from a common history of neglect, and few moments of accomplishment. Although fruit utilization is a customary nutritional habit of Venezuela's... more
Both autochthonous and introduced fruit crops exploitation in Venezuela have suffered from a common history of neglect, and few moments of accomplishment. Although fruit utilization is a customary nutritional habit of Venezuela's inhabitants well before the pre-Columbian times, currently, the per capita consumption of fruits in the country lags slightly below the recommended daily intake. Most of the efforts put into place regarding fruit culture in Venezuela have been mostly devoted to pathogen analysis and control; biotechnological advances have been almost inexistent, other than the development of in vitro tissue culture protocols, and a very poor analysis of the guava germplasm present in the country. In this short report data on guava production, "varieties", cultural practices, ethno-botanical aspects, as well as main pathogens and pests of the crop, will be presented. Some efforts, however, look promising since some institutions (remarkably, Universidad de Los Andes, through the GUAVAMAP project, and Universidad del Zulia, with its long tradition in the fields of phytopathology and agronomical sciences) are investing important financial and human resources to catalog the diversity of Venezuelan guavas, and in the molecular and phenotypical characterization of guava landraces all over the country and the remnants of the first introduced varieties commercially exploited in western Venezuela.
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Papaya ringspot virus (PRSV) is the most important virus affecting papaya and cucurbit plants in tropical and subtropical areas. PRSV isolates are divided into biotypes P and W: both the P and W types naturally infect plants in the family... more
Papaya ringspot virus (PRSV) is the most important virus affecting papaya and cucurbit plants in tropical and subtropical areas. PRSV isolates are divided into biotypes P and W: both the P and W types naturally infect plants in the family Cucurbitaceae, whereas the P type naturally infects papaya (Carica papaya). Understanding the origin and nature of the PRSV genetic diversity and evolution is critical for the implementation of control strategies based on cross-protection and the deployment of transgenic plants that show resistance to virus isolates highly similar to the transgene. The molecular epidemiology of PRSV was evaluated by analyzing the nucleotide sequence of the capsid protein (CP) and helper component-proteinase (HC-Pro) genes of isolates from around the world, including newly characterized ones from Colombia and Venezuela, using a relaxed molecular clock-based approach and a phylogeographic study. Our results confirm previous estimates on the origin of PRSV around 400 years ago and suggest distinct dispersion events from the Indian Peninsula to the rest of Asia, via Thailand, and subsequently to the Americas. A historical reconstruction of the P- and W-type characters in the phylogenetic study supports the need to revise the hypothesis that PRSV-P derives from PRSV-W since our results suggest that the ancestral state could be either of the two biotypes. Moreover, estimates of epidemic growth predict an increasing genetic diversity of the virus over time that has direct implications for control strategies of PRSV based on cross-protection and the use of transgenic plants.
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ABSTRACT Folivory has been reported in only five species of microbats, and described as a seasonal phenomenon. Bats feed on leaves by chewing a portion of leaf, extracting the liquid, and discarding the fibrous material. In the course of... more
ABSTRACT Folivory has been reported in only five species of microbats, and described as a seasonal phenomenon. Bats feed on leaves by chewing a portion of leaf, extracting the liquid, and discarding the fibrous material. In the course of a study on the reproductive pattern of Artibeus amplus in the Venezuelan Andes, leaves were frequently observed in a cave used by this species as a roost. We took this opportunity to (1) identify the leaves consumed by this poorly known Neotropical bat species, and (2) test whether folivory is a temporal phenomenon, such as in other leaf-eating bat species. Artibeus amplus consumes the leaves of seven species of plants, and four of these were found in every month of the year during the study. We report for the first time: (1) folivory in A. amplus, (2) five plant species never reported before in the diet of a bat, and (3) folivory as a non-seasonal phenomenon.
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FIGURE 5. Webbing of the front and hind limbs of the two species of salamanders present in Mérida state (Venezuela), Bolitoglossa Mucuyensis sp. nov. and B. orestes (pictures taken by Moisés Escalona).
FIGURE 2. The original ML tree (1000 bootstrap pseudoreplicates) of the concatenated sequences of cytb + rRNA16S, showing the location of the related salamander species from Cordillera de Mérida (Mérida state) Bolitoglossa mucuyensis sp.... more
FIGURE 2. The original ML tree (1000 bootstrap pseudoreplicates) of the concatenated sequences of cytb + rRNA16S, showing the location of the related salamander species from Cordillera de Mérida (Mérida state) Bolitoglossa mucuyensis sp. nov. (Sierra Nevada de Mérida) and B. orestes (Sierra La Culata) was used to generate the 50% supported tree shown here. The analysis was performed using the GTR model of nucleotide substitution. The tree is drawn to scale, with branch lengths measured in number of substitutions per site (968 sites). The vertical line to the right encompasses the species belonging to the group adspersa.
Coevolution and adaptation between viruses and their hosts are often portrayed as a biological arms race. Viruses are equipped with an array of mechanisms to counteract host defenses that are poised to recognize nonself and activate... more
Coevolution and adaptation between viruses and their hosts are often portrayed as a biological arms race. Viruses are equipped with an array of mechanisms to counteract host defenses that are poised to recognize nonself and activate antiviral pathways, which in turn have driven the development of mechanisms that restrict infection in host organisms across all domains of life. Invariably the opposing goals of the host organism and the virus have led to the dramatic diversification of viruses and host defense responses. In this chapter, we examine various mechanisms developed by each side as a means for survival, and also briefly review the effects of virus infections on the fitness of the host, that is, its overall metabolism and performance.
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Por primera vez se reporta al hongo Thielaviopsis basicola (Berk. & Broome) Ferris, como causa de podredumbre negra en las raices comestibles de yuca amarilla. Para aislar el patogeno se utilizaron cebos preparados con raices frescas y... more
Por primera vez se reporta al hongo Thielaviopsis basicola (Berk. & Broome) Ferris, como causa de podredumbre negra en las raices comestibles de yuca amarilla. Para aislar el patogeno se utilizaron cebos preparados con raices frescas y sanas de zanahoria. El hongo produjo sus estructuras reproductivas sobre raices de yuca infectadas naturalmente y de zanahoria inoculadas experimentalmente. La identidad del organismo se determino sobre la base de las caracteristicas morfometricas de sus estructuras reproductivas y a traves de analisis molecular por secuenciacion de la region genica del rDNA, incluyendo las regiones variables ITS1 e ITS2 . Pruebas de patogenicidad y reaislamientos confirmaron los postulados de Koch.
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Sturnira is the most speciose genus of New World leaf-nosed bats (Phyllostomidae). We name Sturnira adrianae, new species. This taxon is born polytypic, divided into a larger subspecies (S. a. adrianae) widespread in the mountains of... more
Sturnira is the most speciose genus of New World leaf-nosed bats (Phyllostomidae). We name Sturnira adrianae, new species. This taxon is born polytypic, divided into a larger subspecies (S. a. adrianae) widespread in the mountains of northern and western Venezuela, and northern Colombia, and a smaller subspecies (S. a. caripana) endemic to the mountains of northeastern Venezuela. The new species inhabits evergreen, deciduous, and cloud forests at mainly medium (1000–2000 m) elevations. It has long been confused with S. ludovici, but it is more closely related to S. oporaphilum. It can be distinguished from other species of Sturnira by genetic data, and based on discrete and continuously varying characters. Within the genus, the new species belongs to a clade that also includes S. oporaphilum, S. ludovici, S. hondurensis, and S. burtonlimi. The larger new subspecies is the largest member of this clade. The two new subspecies are the most sexually dimorphic members of this clade. The ...
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Transformation plasmid-derived insert number and insert site sequence in 55-1 line papaya derivatives Rainbow and SunUp was determined as part of a larger petition to allow its import into Japan (Suzuki et al., 2007, 2008). Three... more
Transformation plasmid-derived insert number and insert site sequence in 55-1 line papaya derivatives Rainbow and SunUp was determined as part of a larger petition to allow its import into Japan (Suzuki et al., 2007, 2008). Three insertions were detected by Southern analysis and their corresponding sequences determined by clones (Fermin, 2002) or via the whole genome shotgun (WGS) sequence database of SunUp (Ming et al., 2008). All functional transgenes including the coat protein (CP) gene that confers resistance to PRSV, and visible and selectable marker genes, uidA encoding glucuronidase (GUS) and nptII encoding neomycin phosphotransferase II were found in a single 9,789 basepair (bp) insert referred to as the functional transgene. The two other insertion sites consisted of a 290 bp nonfunctional sequence of the nptII gene and a 1,533 bp plasmid-derived fragment containing a nonfunctional 222 bp segment of the tetA gene. Detection of the same three inserts in Rainbow and in samples of SunUp representing transgenic generations five to eight (R5 to R8) suggests that the inserts are stable. Five out of the six genomic DNA segments flanking the three inserts were nuclear plastid sequences (nupts). No changes to endogenous gene function based on sequence structure of the transformation plasmid DNA insertion sites could be determined and no allergenic or toxic proteins were predicted from analysis of the insertion site and flanking genomic DNA. These results should support a positive review of the petition to allow the import and consumption of Rainbow and its derivatives in Japan, which is currently in its final stages. Export of Rainbow papaya to Japan will greatly benefit the local papaya industry in Hawaii and will provide a case for testing consumer acceptance of genetically engineered fresh products in Japan.
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<i>Bolitoglossa mucuyensis</i> sp. nov. (Fig. 3 A–E) La Mucuy salamander (English) Salamandra de La Mucuy (Spanish) <i>B. orestes</i> Barrio-Amorós y Fuentes-Ramos 1999: 29 (in part, MCNC 7557) <i>B.... more
<i>Bolitoglossa mucuyensis</i> sp. nov. (Fig. 3 A–E) La Mucuy salamander (English) Salamandra de La Mucuy (Spanish) <i>B. orestes</i> Barrio-Amorós y Fuentes-Ramos 1999: 29 (in part, MCNC 7557) <i>B. orestes</i> Díaz de Pascual <i>et al</i>. 2010: 41 (in part, CVULA IV- 7099) <b>Holotype.</b> ULABG 1772, adult female from Parque Nacional 'Sierra Nevada', La Mucuy, nearby a stream located between a trout farm and a place called Mesa de Los Pinos, 2225 masl, Santos Marquina municipality, Mérida state, Venezuela. Collected in August 7 th, 1987 by Enrique La Marca (field number ELM 1772), Abraham Mijares (AMU), Juan Elías García Pérez and Maricela Sosa. <b>Paratypes.</b> Same data as the holotype, ULABG 1771 (field number ELM 1771); Parque Nacional 'Sierra Nevada', La Mucuy stream, close to a trout farm and the national park facilities (INParques), 2225 masl, adult males ULABG 1797, 1798, 1800,1805- 1809, adult females ULABG 1799, 1801, 1803, 1804, collected in October 8 th, 1987 by Abraham Mijares and Enrique La Marca (field numbers ELM 1797-1809); National Park Sierra Nevada, La Mucuy cloud forest, sector Bosque del Silencio, 2250 masl, juveniles ULABG 3032, 3034, adult female ULABG 3033, collected in June 21 st, 1989 by Abraham Mijares (field numbers AMU 2223-2225); Parque Nacional 'Sierra Nevada', La Mucuy forest, nearby a trout farm and the national park facilities (INParques), 2200 masl, ULABG 3413, collected in January 7 th, 1993 by Enrique La Marca (field number ELM 3413); Parque Nacional 'Sierra Nevada', La Mucuy Alta, adult female, CVULA IV- 7099, collected in June 17 th, 2008. <b>Diagnosis.</b> Species of reduced size belonging to the <i>adspersa</i> group of species of the <i>Eladinea</i> subgenus as defined by Parra-Olea <i>et al</i>. (2004), and corroborated by the molecular data reported by Fermin <i>et al</i>. (2012) and those derived from the present work (Fig. 2). Assigned to <i>Bolitoglossa</i> because it lacks a sublingual fold. <i>B.</i> <i>mucuyensis</i> <b>sp. nov.</b> differs from all other Ve [...]
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FIGURE 1. Geographical representation of the distribution of Venezuelan salamanders, and of the collecting sites nearby Mérida city sampled in this and previous works. A Salamanders of the genus Bolitoglossa reported for Venezuela include... more
FIGURE 1. Geographical representation of the distribution of Venezuelan salamanders, and of the collecting sites nearby Mérida city sampled in this and previous works. A Salamanders of the genus Bolitoglossa reported for Venezuela include B. borburata (1), B. guaramacalensis (2), B. orestes (3), B. spongai (4) and B. altamazonica (5), for which the corresponding type localities are drawn as white circles. B Location of the geographical region in Cordillera de Mérida chosen for sampling efforts at cloud forests nearby Mérida city; the box in white is drawn at bigger scale in C. C Sampling locations are drawn as inverted black triangles at different places of Sierra La Culata and Sierra Nevada de Mérida; the map shows the main geographical features in, and between, both local Andean ranges.
FIGURE 3. Original ML tree (500 bootstrap pseudoreplicates), showing the location of the sister salamander species from Cordillera de Mérida (Mérida state), B. orestes (Sierra La Culata) and La Mucuy salamander (Bolitoglossa sp. nov.,... more
FIGURE 3. Original ML tree (500 bootstrap pseudoreplicates), showing the location of the sister salamander species from Cordillera de Mérida (Mérida state), B. orestes (Sierra La Culata) and La Mucuy salamander (Bolitoglossa sp. nov., Sierra Nevada de Mérida). The analysis was performed using default parameters (Kimura 2-parameter model, with uniform substitution rates among sites). The tree is drawn to scale, with branch lengths measured in the number of substitutions per site.
FIGURE 2. Bivariate plot of SVL vs. VT (A) and SVL vs. MT (B) using the data published in the original description of B. orestes (black boxes) and B. spongai (black circles) as reported by Brame & Wake (1962) and Barrio-Amorós & Fuentes-... more
FIGURE 2. Bivariate plot of SVL vs. VT (A) and SVL vs. MT (B) using the data published in the original description of B. orestes (black boxes) and B. spongai (black circles) as reported by Brame & Wake (1962) and Barrio-Amorós & Fuentes- Ramos (1999), respectively, as well as those specimens morphologically analyzed at CVULA that were registered as B. orestes (white boxes) or B. spongai (white circles) based on prior references of geographical distribution. A vertical arrow points to the holotype of each species, while numbers refer to those specimens used for morphological characterization (CVULA), and that were also a part of the set of DNA samples utilized for the molecular analysis described here: 1, IV-7093; 2, IV-7094; 3, IV- 7096; 4, IV-7100; 5, IV-7104; 6, IV-7107;7, IV-7108; and 8, IV-7110.
FIGURE 1. Type locality of Bolitoglossa mucuyensis sp. nov. (A) The type locality of the species is placed in the proximities of La Mucuy, Mérida state (white asterisk); the line oriented NW/SE is shown in 'B' with more details.... more
FIGURE 1. Type locality of Bolitoglossa mucuyensis sp. nov. (A) The type locality of the species is placed in the proximities of La Mucuy, Mérida state (white asterisk); the line oriented NW/SE is shown in 'B' with more details. (B) Relief profile from south Lake Maracaibo, passing through Sierra La Culata and Sierra Nevada de Mérida with the homonymous city between them, to the Llanos of Barinas; modified from Vivas (2007). (C) A detailed depiction of La Mucuy in Sierra Nevada de Mérida, very close to the capital city of the state to the left (the type locality is shown with a white asterisk).
Viruses have evolved a number of strategies to overcome the intracellular and extracellular barriers of the host cell in order to efficiently and rapidly replicate their genomes. An understanding of these mechanisms has allowed scientists... more
Viruses have evolved a number of strategies to overcome the intracellular and extracellular barriers of the host cell in order to efficiently and rapidly replicate their genomes. An understanding of these mechanisms has allowed scientists to exploit and manipulate viruses as vehicles of therapeutic agents, either as delivery vehicles for heterologous genetic material (gene therapy) or as infectious agents with inherent cytotoxic activity (oncolytic virus therapy). Animal viruses, along with bacterial and plant viruses, are playing prominent roles in this area of research and development, thus widening the realm of capabilities for our benefit. In some instances, phages per se are being used for the development of therapies aimed at deterring old enemies, pathogenic bacteria. Besides manipulating viruses’ genomes, virions as materials with new functionalities have relevance in nanotechnology and are slowly, and safely, appearing in our daily lives.
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Viruses have played a major role in 20th-century Biology and continue to serve as ideal tools for the dissection of the most intricate life processes. Initially, much of the early studies were focused on deciphering the nature of these... more
Viruses have played a major role in 20th-century Biology and continue to serve as ideal tools for the dissection of the most intricate life processes. Initially, much of the early studies were focused on deciphering the nature of these unique entities, their interactions with hosts and pathogenesis. Much of what has been learnt proved applicable to understanding of the nature and structure of genes, how genes and genomes operate and how genetic information is replicated over generations. Scientists have since rapidly harnessed the biology of the viruses for the development of new tools and applications in molecular biology, medicine, and agriculture. It is interesting that the very traits employed by viruses to establish infection and induce disease in their hosts are now being manipulated for the production of vectors and biologics that are safe and efficacious. Indeed the convergence of biology, genetics, biochemistry, and physics has propelled the development of molecular biology...
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En los murcielagos, las senales quimicas son particularmen - te importantes para comunicarse. Aunque el olor de los fluidos corporales puede ser importante p...
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During the last few decades, over 20 plant virus species capable of infecting papaya (Carica papaya L.) have emerged in tropical and subtropical regions. The extent and severity of disease symptoms vary widely from minor or unapparent to... more
During the last few decades, over 20 plant virus species capable of infecting papaya (Carica papaya L.) have emerged in tropical and subtropical regions. The extent and severity of disease symptoms vary widely from minor or unapparent to reduced tree vigor, yield, and impaired fruit quality. Existing data on molecular characteristics of viruses infecting papaya also vary; while phenotypic data are available for the majority, the genotype of many have not been characterized and partial or complete nucleotide sequences have not been determined. As a result, some virus species are classified in recognized taxa while others are tentatively assigned to genera or have not been sufficiently distinguished from viruses in recognized genera so as to form a new genus. This paper presents an overview of the virus species capable of infecting papaya, diseases they elicit, genetic structure and diversity, and factors contributing to their emergence where molecular data are available.
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Viruses, as they replicate in the plant host, can disrupt cellular processes and host physiology to cause disease. The range in disease reactions, from yellowing to dwarfing and reduction in host fecundity, culminates in sizable losses... more
Viruses, as they replicate in the plant host, can disrupt cellular processes and host physiology to cause disease. The range in disease reactions, from yellowing to dwarfing and reduction in host fecundity, culminates in sizable losses along with decreases in the aesthetic value in commercial cultivations, landscape plants, or home gardens. Typically, these reactions occur in plants that have not developed specific defensive responses against virulence factors produced by the virus. However, there can be instances where plants, in both natural and cultivated populations, carry inherent disease resistance but are not protected against virus infections. Successful disease management strategies are therefore aimed at the prevention or the reduction of virus infections and require an understanding of how viruses survive and spread between crops and across seasons. Since different diseases have distinct ecological and epidemiological characteristics, there is no “ one-size-fits-all ” approach to management. Diseases caused by plant viruses affecting cassava, sweet potato, banana, corn, rice, wheat, and various vegetable crops are examined in this chapter.
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Prokaryotes, unicellular eukaryotes, and small eukaryotes harbor remarkable viral diversity. In some examples, the virions are the largest ever described, shattering notions that viruses cannot be seen with a light microscope, whereas... more
Prokaryotes, unicellular eukaryotes, and small eukaryotes harbor remarkable viral diversity. In some examples, the virions are the largest ever described, shattering notions that viruses cannot be seen with a light microscope, whereas others are considered endogenous viral elements without an extracellular phase. They exhibit far greater genomic flexibility, encoding proteins that have never been previously identified in viruses, but have closely related eukaryotic homologs. Curiously, they can infect species across two or three different kingdoms. Host interactions are variable and range from mutualism, in some cases involving an improvement of the adaptation abilities of the host toward biotic or abiotic stress, to severe host impairment including irregular growth and reduced reproduction of the infected host. Together, these viruses present a view of the virosphere as more phylogenetically and genomically diverse than that previously predicted. They provide a solid foundation for future studies in virus ecology and evolution.
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This chapter focuses on some of the topics that are of current interest and relevance to tropical and subtropical regions where a number of plant diseases that threaten food security are caused by viruses. It describes the biology... more
This chapter focuses on some of the topics that are of current interest and relevance to tropical and subtropical regions where a number of plant diseases that threaten food security are caused by viruses. It describes the biology (structure, taxonomy and diversity), evolution, reservoir hosts (wild and non-crop plants), interactions with viruses, plants and vectors, diagnosis, and control of plant viruses.
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In this chapter, we summarize recent advances in our understanding of the positive, regulatory roles played by viruses in the environment, as well as the surprising beneficial outcomes derived from some virus–host interactions. A... more
In this chapter, we summarize recent advances in our understanding of the positive, regulatory roles played by viruses in the environment, as well as the surprising beneficial outcomes derived from some virus–host interactions. A different view of viruses is emerging and more and more studies on the relationships between cellular organisms and the viruses that infect them challenge the portrayal of viruses as only infectious agents of disease. Viruses, without the intervention of human-devised strategies, regulate biogeochemical cycling of nutrients and trace elements, they help cellular organisms cope with abiotic agents of stress; and in some instances, they keep other viruses and cellular pathogens under check. Even more, viruses appear to have shaped the many ways prokaryotes and eukaryotes have changed over time; they have contributed to the emergence of new traits thanks to the exaptation of genes (and hence, proteins) of viral origin. There is a world of yet unknown viruses; forthcoming exploration of viruses across all ecosystems promises to provide further insight into the many dimensions of virus–host relationships.
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In the last decade, successful cases of managing plant virus diseases using the transgenic approach have been reported, with the best known example being the Papaya ringspot virus (PRSV)-resistant transgenic papayas in Hawaii. Use of the... more
In the last decade, successful cases of managing plant virus diseases using the transgenic approach have been reported, with the best known example being the Papaya ringspot virus (PRSV)-resistant transgenic papayas in Hawaii. Use of the coat protein (cp) gene has proven effective with not only papaya, but with various plant-virus systems such as squash. Although other viral sequences are equally effective in conferring resistance, few transgenic plants engineered with these sequences have made their way into the market. In addition, opposition to genetic manipulation of crop plants has prevented wide application of the technology, despite the fact that many countries (including Jamaica, Brazil and Venezuela) have produced and characterized several generations of resistant transgenic papayas. Using the papaya-PRSV system as a case study, we examine the transgenic cropping systems available, constraints to the adoption of transgenic papayas in various countries, as well as the impact...
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Este libro trata sobre los Reinos de la Naturaleza, es decir, sobre los diversos conjuntos de seres vivientes que existen en este maravilloso Planeta Tierra, y la manera como ellos son agrupados en categorías elaboradas por especialistas... more
Este libro trata sobre los Reinos de la Naturaleza, es decir, sobre los diversos conjuntos
de seres vivientes que existen en este maravilloso Planeta Tierra, y la manera como ellos
son agrupados en categorías elaboradas por especialistas para lograr entender sus
complejas estructuras y funcionamientos, y apreciar tentativamente el camino seguido en
su evolución desde el momento en que se originó la vida en el Planeta. Los seres vivientes
han tomado distintas formas para organizarse y sobrevivir, con facilidad o con dificultad,
en los ambientes terrestres y acuáticos, y han seguido muy distintas rutas para su
desarrollo en la exquisita geografía planetaria, la cual se ha ido modificando en paralelo y
a consecuencia de la existencia de ellos mismos. Lo inanimado inicial, mineral, permitió
la aparición de la vida, la cual ha modificado luego todos los sustratos ambientales, en un
camino evolutivo interminable
de seres vivientes que existen en este maravilloso Planeta Tierra, y la manera como ellos
son agrupados en categorías elaboradas por especialistas para lograr entender sus
complejas estructuras y funcionamientos, y apreciar tentativamente el camino seguido en
su evolución desde el momento en que se originó la vida en el Planeta. Los seres vivientes
han tomado distintas formas para organizarse y sobrevivir, con facilidad o con dificultad,
en los ambientes terrestres y acuáticos, y han seguido muy distintas rutas para su
desarrollo en la exquisita geografía planetaria, la cual se ha ido modificando en paralelo y
a consecuencia de la existencia de ellos mismos. Lo inanimado inicial, mineral, permitió
la aparición de la vida, la cual ha modificado luego todos los sustratos ambientales, en un
camino evolutivo interminable