The lack of geographic isolation as a definitive barrier between sympatric species has yielded controversy among ecologists, biologists, and zoologists regarding the validity of the term. As such, researchers have long debated the conditions under which sympatry truly applies, especially with respect to parasitism. Because parasitic organisms often inhabit multiple hosts during a life cycle, evolutionary biologist Ernst Mayr stated that internal parasites existing within different hosts demonstrate allopatry, not sympatry. Today, however, many biologists consider parasites and their hosts to be sympatric (see examples below). Conversely, zoologist Michael J. D. White considered two populations sympatric if genetic interbreeding was viable within the habitat overlap. This may be further specified as sympatry occurring within one deme; that is, reproductive individuals must be able to locate one another in the same population in order to be sympatric. Others question the ability of sympatry to ...
Information portal for reptile and amphibian hobbyists offering classifieds, forums, photo galleries, events, business listings and much more for various species
A capture rate is a type of calculation that is used to express the number of items that a process is able to pull from a larger...
Cryptic sympatric species arise when reproductive isolation is established in sympatry, leading to genetically divergent lineages that are highly similar morphologically or virtually indistinguishable. Although cryptic sympatric species have been reported in various animals, fungi, and protists, there are few compelling examples for plants. This investigation presents a case for cryptic sympatric speciation in Najas flexilis, a widespread aquatic plant, which extends throughout northern North America and Eurasia. The taxon is noted for its variable seed morphology, which earlier research associated with cytotypes; i.e., diploids were characterized by thicker seeds and tetraploids by thinner seeds. However, cytotypes are not patterned geographically with diploid and tetraploid plants often found in close proximity within the same lake. Using digital image and DNA sequence analyses, we found that diploids and tetraploids are well-isolated and remain genetically distinct throughout their sympatric ...
A group at Monash University has been using the spiny mouse in studies of fetal programming and sex-dependent effects of glucocorticoids on placental development (here). The spiny mouse holds great promise as a new model for placental and fetal development. Moreover, its potential for studies in a quite different area, tissue regeneration (here), means it is likely to be come more widely available as a laboratory animal. ...
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Sherry, Jessica Lynne, "Ecological Divergence Among Extremely Close Relatives in Bacillus" (2013). Honors Theses - All. 1103 ...
Zoonotic Viruses Associated with Illegally Imported Wildlife Products K. Smith et al.| PLoS ONE | January 2012  Abstract: The global trade in wil...
Sigma-Aldrich offers abstracts and full-text articles by [Sophie A Montandon, Athanasia C Tzika, António F Martins, Bastien Chopard, Michel C Milinkovitch].
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We studied temporal partitioning between two spiny mouse species that coexist in hot rocky deserts in the Middle East: nocturnal common spiny mice (Acomys cahirinus) and diurnally active golden spiny mice (A. russatus). Although A. russatus is diurnally active, it retains the physical activity and body temperature rhythms of nocturnal mammals. We studied the two species in four 1000-m 2 enclosures at Ein Gedi, Israel: two experimental enclosures with A. russatus kept alone, and two controls with individuals of both species kept together. We monitored activity with Sherman traps and by studying foraging microhabitat use and efficiency using giving-up densities (GUDs) in food trays. The trays contained broken sunflower seeds mixed in local soil and placed in three micro- habitats: under boulders, between boulders, and in the open. Trapping revealed that, in the absence of A. cahirinus, the usually diurnal A. russatus was active both day and night. However, during the day A. russatus still foraged in
The chromosome analysis of the masculinized hybrid between female Tanakia limbata and male T. signifer in bitterlings (Acheilognathinae) was done. It was presumed that they had intermediate karyotype between the parents, and formed sperms with heteroploidy resulting from the incomplete pairing of homologous chromosomes in meiosis. Due to the abundance of species and the ease of artificial fertilization, the study of the factor of the hybrid sterility in bitterlings would lead to the clarification of the mechanism about species differentiation and karyotype differentiation, and also to developing a new variety.
Definition: Monthly PET (Potential Evapotranspiration Rate) within the geographic range of a taxon. Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earths land surface to atmosphere. Potential evapotranspiration (PET) is a representation of the environmental demand for evapotranspiration and represents the evapotranspiration rate of a short green crop, completely shading the ground, of uniform height and with adequate water status in the soil profile. It is a reflection of the energy available to evaporate water, and of the wind available to transport the water vapour from the ground up into the lower atmosphere ...
Insects represent the worlds largest group of organisms, comprising over 900 000 described species, which is about 70% of all animal species [1]. Their species richness and biological diversity make insects key players in almost every terrestrial ecosystem. Many explanations for this hyperdiversity focus on the ecological niche and on ecological speciation [2]. Central to the concept of ecological speciation is that populations of the same species become genetically isolated because they specialize in different ecological niches [3-5]. This is assumed to result in the evolution of new species owing to restricted gene flow between populations, in allopatry as well as in sympatry [6]. One problem with the concept of ecological speciation is that it must be initiated by the switch of particular individuals of a population to a new ecological niche (e.g. a new host in herbivorous or parasitoid insects) to which they are not yet adapted. It is unclear why the offspring of these pioneers should ...
Mating between sympatric species is a regular occurrence in natural populations, and increasing anthropogenic re-distributions of organisms is driving ever greater frequencies of species contact and hybridization [1, 2]. Whether giving rise to new, independent hybrid lineages or to the movement of alleles between species (i.e. introgression), recent population genetics and experimental studies show that inter-specific mating can be a major force behind adaptation and speciation [3-5]. The potential for hybridization to contribute to biodiversity, however, involves the interactions of multiple processes that remain incompletely understood [6]. In particular, hybridization is limited by a complex interplay of pre- and post-mating reproductive barriers that can decrease mating compatibility between species or the fitness of hybrid individuals [2].. Especially in sympatric species, isolating mechanisms that depend on mating behaviors (i.e. compatibilities of different sexes or mating types) play a ...
The marginal value theorem (MVT) is an optimality model that usually describes the behavior of an optimally foraging individual in a system where resources (often food) are located in discrete patches separated by areas with no resources. Due to the resource-free space, animals must spend time traveling between patches. The MVT can also be applied to other situations in which organisms face diminishing returns. The MVT was first proposed by Eric Charnov in 1976. In his original formulation: "The predator should leave the patch it is presently in when the marginal capture rate in the patch drops to the average capture rate for the habitat." All animals must forage for food in order to meet their energetic needs, but doing so is energetically costly. It is assumed that evolution by natural selection results in animals utilizing the most economic and efficient strategy to balance energy gain and consumption. The Marginal Value Theorem is an optimality model that describes the strategy that ...
Our data provide no evidence that positive selection is enhanced in sympatry, and if these candidate GRPs are involved in prezygotic isolation, we have no evidence for enhanced prezygotic isolation. The polymorphism statistics likewise give no indication that RCD is occurring in these three proteins.. We cannot necessarily conclude from lack of evidence for RCD in CIPRO37.40.1, CIPRO60.5.1 and CIPRO100.7.1 that RCD is not occurring in this system. If enhanced prezygotic isolation between Type A and B does exist, there are several reasons why we might not have detected it in this study. First, primers for candidate GRPs were developed from the Type A genomic sequence and were used to amplify and sequence both Type A and B individuals (the Type B genome has not been sequenced). But Type A and B are substantially divergent (p-distances: 0.124 at mtCOI, 0.035 to 0.116 for six nuclear loci; [43]), which could explain why 15 genes encoding GRP candidates could not be successfully amplified and/or ...
Dogon Marké local information and maps. Dogon Marké is a populated place in Maradi, Niger, Africa. Dogon Marke is also known as Dongo Marke, Dongo Marké.
In forest clearings of the Malaysian rainforest, chirping and trilling Mecopoda species often live in sympatry. We investigated whether a phenomenon known as stochastic resonance (SR) improved the ability of individuals to detect a low-frequent signal component typical of chirps when members of the heterospecific trilling species were simultaneously active. This phenomenon may explain the fact that the chirping species upholds entrainment to the conspecific song in the presence of the trill. Therefore, we evaluated the response probability of an ascending auditory neuron (TN-1) in individuals of the chirping Mecopoda species to triple-pulsed 2, 8 and 20 kHz signals that were broadcast 1 dB below the hearing threshold while increasing the intensity of either white noise or a typical triller song ...
The damselflies belong to the sub-order Zygoptera. Damselflies are usually smaller and more delicate looking than dragonflies and they tend to close
Sympatric and parapatric speciation refer to theorigin of biological species in the absence of complete geographic isolation between the diverging taxa
Paralarvae of G. fabricii are most easily separated from the partially sympatric species, G. steenstrupi, by the presence two large chromatophores on the ventral surface of the head in G. fabricii vs none in G. steenstrupi. This difference distinguishes the adults as well. The full chromatophore pattern of the paralarva is not known. The number of suckers on arms I-IV is useful at sizes greater than 13 mm ML as is the form of the funnel organ in all but smallest paralarvae. The paralarval stage appears to end at about 20 mm ML which corresponds with hook development and movement into deeper water (Falcon, et al., 2000).. ...
Paralarvae of G. fabricii are most easily separated from the partially sympatric species, G. steenstrupi, by the presence two large chromatophores on the ventral surface of the head in G. fabricii vs none in G. steenstrupi. This difference distinguishes the adults as well. The full chromatophore pattern of the paralarva is not known. The number of suckers on arms I-IV is useful at sizes greater than 13 mm ML as is the form of the funnel organ in all but smallest paralarvae. The paralarval stage appears to end at about 20 mm ML which corresponds with hook development and movement into deeper water (Falcon, et al., 2000).. ...
By Arlen Cellana. North Adams, MA - Severe Acute Respiratory Syndrom has killed nearly 80 people 46 in China and infected more than 2,300 worldwide and has been making news around the country, including two possible cases in Rensselaer County, New York. On Saturday, a group of students from the Mass. College of Liberal Arts in North Adams returned from a two week trip to China. Berkshire Bureau Chief Arlen Cellana wondered what precautions the school and local health officials are taking to monitor the health of the returnees.. ...
In this video Dr. Geraint Wilde, Product Specialist for Microscopy at Andor Technology, discusses the Revolution XD family of flexible system solutions focused on live cell imaging. In offering the new Neo sCMOS, iXon Ultra EMCCD and the 10,000 rpm CSU-X from Yokogawa®, Andor offers unprecedented image capture rates for high speed applications. Dr. Wilde also tells SelectScience about the Revolution DSD for laser-free confocal microscopy. The Revolution DSD is an innovative hybrid of spinning disk technology and structured illumination. Interview filmed by SelectScience at EMC 2012.
Selective advantage of sexual over asexual reproduction (rmm = 0, rmM = 0, rMM = 0.1) (a,c) and of high over low recombination (b,d) in both the standard model
অযৌন প্ৰজনন(Asexual reproduction) প্ৰতিকূল পৰিবেশত কিছুমান বেক্টেৰিয়াই (যেনে-বেচিলাছ আৰু ক্লছট্ৰিডিয়াম) কোষত কোষপ্ৰৰসখিনি সংকুচিত হয় আৰু ইয়াৰ চাৰিওফালে এখন ডাঠ আৱৰণৰ সৃষ্টি হয়৷ ডাঠ আৱৰণেৰে সৈতে কোষস্থ সংকুচিত কোষপ্ৰৰসখিনিক অন্ত:ৰেণু(endospore) বোলে৷ অনুকূল পৰিবেশত অন্ত:ৰেণু বেক্টেৰিয়া কোষবেৰ ফাটি ওলাই আহে আৰু অংকুৰিত হৈ অপত্য বেক্টেৰিয়াৰ সৃষ্টি কৰে৷ ইয়াৰ বাহিৰেও কিছুমান বেক্টেৰিয়া ...
Define propagate: to cause to continue or increase by sexual or asexual reproduction; to pass along to offspring - propagate in a sentence
The beating of your heart is very organized, taking its cue from a built-in electrical system. A normal heart rate is regular, at 60 to 100 beats per minute. An arrhythmia is any kind of abnormal heartbeat-too fast, too slow, or irregular. This video explains different arrhythmias and what you should do if you have one. ...more ...
While the effect of Operational Sex Ratio (OSR) on reproductive behaviour of males has been studied extensively, little is known of the response of females facing a female-biased OSR. We investigated the effect of different OSRs on female reproductive behaviour using the rosy bitterling, Rhodeus ocellatus, a freshwater fish that lays its eggs inside the gills of living freshwater mussels. Three levels of OSR (male/female ratio 1:1, 1:3 and 1:5) were tested. We demonstrated that inspection of the mussel (spawning substrate) by individual females increased with increasingly female-biased OSR, but that the rate of following territorial male decreased. Aggression towards other females was not affected by the OSR. Interestingly, when a male bitterling led a non-dominant female towards the mussel, the dominant female would become aggressive to the male and chase the non-dominant female away. Aggression towards male followed a bell-shaped pattern and was highest at an OSR of 1:3. In both the female-biased OSRs
Animals can gain important information by attending to the signals and cues of other animals in their environment, with acoustic information playing a major role in many taxa. Echolocation call sequences of bats contain information about the identity and behaviour of the sender which is perceptible to close-by receivers. Increasing evidence supports the communicative function of echolocation within species, yet data about its role for interspecific information transfer is scarce. Here, we asked which information bats extract from heterospecific echolocation calls during foraging. In three linked playback experiments, we tested in the flight room and field if foraging Myotis bats approached the foraging call sequences of conspecifics and four heterospecifics that were similar in acoustic call structure only (acoustic similarity hypothesis), in foraging ecology only (foraging similarity hypothesis), both, or none. Compared to the natural prey capture rate of 1.3 buzzes per minute of bat activity, ...
TY - JOUR. T1 - Gene flow between sexual and asexual strains of parasitic wasps. T2 - A possible case of sympatric speciation caused by a parthenogenesis-inducing bacterium. AU - Adachi-Hagimori, Tetsuya. AU - Miura, Kazuki. AU - Abe, Yoshihisa. PY - 2011/6. Y1 - 2011/6. N2 - Sympatric speciation is strictly defined as the emergence of two species from a population in which mating has been random with respect to the place of birth of the mating partners. Mathematical models have shown that sympatric speciation is possible, but very few examples have been documented in nature. In this article, we demonstrate that arrhenotokous and thelytokous strains of a parasitic wasp, Neochrysocharis formosa, speciated sympatrically through infection by a symbiotic bacterium Rickettsia for the following reasons: First, Rickettsia infection was detected in all of the thelytokous strains collected throughout Japan. Second, the arrhenotokous and thelytokous strains have been collected sympatrically. Third, ...
Niche relationships of four sympatric species of whiptail lizards, Cnemidophorus, were studied during 1964 and 1965, along the Rio Grande near Mesilla, Dona Ana County, New Mexico. Comparisons among Cnemidophorus tigris, C. perplexus, C. exsanguis and C. inornatus were based on size, habitat distribution, food habitats, reproduction, and temperature relationships. Significant size differences exist among the species as well as sexual dimorphism in C. tigris, with males the larger. The distribution of C. tigris and C. perplexus in 1964 remained separate from those of C. exsanguis and C. inornatus, but in 1965 all ranges overlapped. All expanded their ranges, except C. exsanguis, which remained the same. Increased in 1965 with more food probably permitted the increased of usable habitat. Competition for food was not evident between C. exsanguis and C. inornatus. There was a strong possibility of competition, however, between C. tigris and C. perplexus since they occupied the same habitat and had ...
When an animal is injured, immune cells such as macrophages rush to the wounded site to clear debris and help repair the damage. Macrophages come in different forms and subtypes, and express different protein markers on their surface, depending on where in the body they reside. Few mammals can completely renew or regrow a damaged tissue - a process known as tissue regeneration. Instead, humans and most other mammals repair injuries by producing scar tissue, which has different properties compared to the original tissue it replaces. One exception is the African spiny mouse (Acomys cahirinus), which, unlike other rodents studied, can regrow skin and fur, nerves, muscles, and even cartilage. It has been shown that in highly regenerative animals such as salamanders and zebrafish, macrophages are necessary to initiate tissue regeneration. Documented cases of tissue regeneration in mammals are rare and therefore less understood. Until now, it was not clear why two species as closely related as spiny ...
Crenicichla cf. dorsocellata. Group: Lacustris Distribution: This specimen was collected in Rio Ribeira. It is occasionally exported from the Campos area in southeastern coastal Brazil. Size: 8 - 10 inches. Type Locality: Rio Parahyba at Campos, Brazil Comments: This infrequently imported southern species is often the only member of the lacustris group found in North America. I saw this species offered for sale in 1993 and bought some. I have yet to see it on any importers list since. While it was sold to Herr Endisch as C. sp. Rio Ribeira, it is what I believe to be C. dorsocellata. Ploeg does not treat it as a valid species, but rather as a synonym of C. lacustris. This might well be the case. We shall find out when Kullander et al. finally publish the long-awaited revision of the lacustris group pikes. So, in the meantime, Ill call it C. cf. dorsocellata. Husbandry of this fish is not difficult when it concerns water quality and feeding - they are not particular about either. Aggression, ...
Del Portillo H.A.; Dimock R.V.Jr, 1982: Specificity of the host induced negative photo taxis of the symbiotic water mite unionicola formosa
A recent study of a pair of sympatric species of palms on the Lord Howe Island is viewed as providing probably one of the most convincing examples of sympatric speciation to date. Here we describe and study a stochastic, individual-based, explicit genetic model tailored for this palms system. Overall, our results show that relatively rapid (, 50 000 generations) colonization of a new ecological niche, and sympatric or parapatric speciation via local adaptation and divergence in flowering periods are theoretically plausible if (i) the number of loci controlling the ecological and flowering period traits is small; (ii) the strength of selection for local adaptation is intermediate; and (iii) an acceleration of flowering by a direct environmental effect associated with the new ecological niche is present. We discuss patterns and time-scales of ecological speciation identified by our model, and we highlight important parameters and features that need to be studied empirically in order to provide ...
This model remained a theoretical and hypothetical, but intriguing, explanation for less than a year. A few weeks ago, researchers from the University of Bern in Switzerland published an empirical experiment that proves it. David Marques and colleagues demonstrated that a population of stickleback fish that breed in the same lake (Lake Constance, where they were introduced around 150 years ago) was splitting into two separate species before their eyes, and at rapid speed. The study shows that even if both types of fish breed in the same streams at the same time of year and have been interbreeding all along, they are splitting into two genetically and physically different types.. It has been argued that true sympatry may not exist in nature, or can be - at least - genetically constrained - wrote Roberto Cazzolla Gatti in his paper (Cazzolla Gatti R., A conceptual model of new hypothesis on the evolution of biodiversity, Biologia, 71(3), 343-351, 2016) - This is because small variations in the ...
Aim We test whether populations of the Mesoamerican azure-crowned hum- mingbird, Amazilia cyanocephala (Trochilidae), located east and west of the Isthmus of Tehuantepec are genetically, morphologically and environmentally differentiated and examine the relative role of drift and selection in driving diversification. Location Mexico. Methods We sequenced the mitochondrial ATPase-6 and ATPase-8 genes and the control region of 130 individuals collected throughout the range of the spe- cies in Mexico. Population genetic methods and coalescent tests were used to reconstruct the phylogeography of the species. Morphological and niche varia- tion between genetic groups of A. cyanocephala were assessed. Results The data revealed two genetic groups separated by the Isthmus of Tehuantepec in the late Pleistocene (49,300-75,800 years ago), with the split occurring in the presence of gene flow. Deviations from demographic equilibrium were detected for the two genetic groups, indicating more recent ...
MATERIALS AND METHODS: The 2 categorization methods were method A, based on nodule size ≥10 mm, and method B, a 3-tiered system based on aggressive imaging features, patient age younger than 35 years or nodule size of ≥15 mm. In part 1, the 2 categorization methods were applied to thyroid cancers in the SEER data base of the National Cancer Institute to compare the cancer capture rates and survival. In part two, 755 CT neck scans at our institution were retrospectively reviewed for the presence of ITNs of ≥5 mm, and the same 2 categorization methods were applied to the CT cases to compare the number of patients who would theoretically meet the criteria for work-up. Comparisons of proportions of subjects captured under methods A and B were made by using the McNemar test.. ...
Asexual Reproduction Asexual reproduction involving only one parent organism. The offspring created through asexual reproduction have the exact same genetic material as the parent; the offspring is a clone of its parent. The production of offspring is usually external so the parent can have lots of offspring in a very short amount of time. There is no parental care required; […]. ...
Some organisms reproduce sexually while others reproduce asexually. Define both types of reproduction. What are the advantages and disadvantages of reproducing each way? Name two organisms that reproduce sexually and two that.
What is asexual reproduction. Asexual reproduction is reproduction without sex. In this form of reproduction, a single organism or cell makes a copy of itself. The genes of the original and its.
Some organisms, such as plant and fungi reproduce asexually by mitosis. For example yeast, a single-celled micro-organisms, reproduce asexually by budding which uses mitosis:. 1. A bud forms on the cells surface.. 2. The D,N,A and organelles replicate. 3. The cell undergoes mitosis.. 4. Nuclear division is complete, the budding cell has identical D,N,A.. …. ...
In southern West Siberia, as many as four Leptidea Billberg, 1820 species are present sympatrically: L. amurensis (Ménétriés, 1859), L. morsei (Ménétriés, 1859), L. sinapis (Linnaeus, 1758) and L. juvernica Williams, 1946. The two latter were recently recognised as nearly sibling species on morphological and molecular characters. Specimens intermediate as to their subtle diagnostic characters occurring in West Siberia and elsewhere were interpreted as resulted from limited introgression. This supposition was tested via populational morphological and molecular analysis of spring brood specimens of all the four species taken from a limited (4.5 × 0.2 km) area in the suburbs of Novosibirsk. The samples were analysed with respect to the genitalic morphology, external characters, three nuclear (CAD, H1 gene and ITS2) and one mitochondrial (COI) molecular markers, infection of the intracellular maternally inherited bacterial symbiont Wolbachia Hertig, 1836 and its wsp gene coding for a hypervariable
Asexual reproduction is the mode of reproduction in prokaryotes. In particular, prokaryotes reproduce through binary fission. Eukaryotes, especially higher forms of animals, reproduce through sexual means, i.e. by sexual reproduction. In sexual reproduction, gametes are produced by meiosis. A male gamete fertilizes the female gamete, forming a zygote. Some eukaryotes are capable of asexual reproduction. In asexual reproduction, the organism is capable of reproducing an offspring in the absence of a mate. As a result, the offspring is a clone of the parent and therefore results in low genetic variation in the species as a whole. Some species are capable of heterogamy, i.e. the ability to alternate between sexual and asexual reproduction. ...
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Are you two twins? Asexual Reproduction: Asexual Reproduction: -Used by many unicellular organisms, plants, and lower animals. -Involves only mitotic cell division = each offspring has exactly the same heredity as its parent. -Usually rapid compared to sexual reproduction. Types of Asexual Reproduction Include:
SAN JUAN, Puerto Rico (AP) - Pop singer Jennifer Lopez may be thinking life is funny after a group of scientists named a water mite in her honor after discovering a new species near Puerto Rico.
Damselfly larva gill. Polarised light micrograph of a section through the gill of a damselfly (suborder Zygoptera) larva (nymph), showing the fine branching airways. The nymphs of damselflies are aquatic and therefore use gills to breath. Magnification: x100, when printed 10cm wide. - Stock Image C025/3742