Contact hybridization in the Crinia laevis complex (Anura : Leoptodactylidae)

1971 ◽  
Vol 19 (1) ◽  
pp. 85 ◽  
Author(s):  
MJ Littlejohn ◽  
GF Watson ◽  
JJ Loftus-Hills
Keyword(s):  
Environmental Factors ◽  
Hybrid Zone ◽  
Acoustic Analysis ◽  
Backcross Progeny ◽  
Geographic Ranges ◽  
Call Structure ◽  
Mating Call ◽  
High Level ◽  
Western Victoria ◽  
Different Parts

Mating-call structure was used to determine the nature and extent of an interaction between the two morphologically indistinguishable taxa, C. laevis and C. victoriana, where their geographic ranges contact in south-western Victoria. Intermediacy of mating-call structure was detected in a zone about 115 km long and less than 2 km wide. Acoustic analysis of call samples from six localities indicated that hybrids, backcross progeny, and one or both parental types were present in this zone. Results of reciprocal artificial hybridization tests between allopatric individuals of the two taxa showed that there was a high level of interfertility in both combinations, but with slightly reduced survival to metamorphosis. Presumed backcrosses using males from the hybrid zone resulted in a higher level of survival to metamorphosis. The zone does not coincide with any conspicuous ecotone and presumably represents a complex balance point with various environmental factors contributing to a greater or lesser extent in different parts of the contact. In spite of this lack of reproductive isolation, the narrowness of the zone and the presumed antiquity of the contact demonstrate that the taxa will continue to maintain their distinctness, and should retain their specific status.

The litoria ewingi complex (Anura : Hylidae) in south-eastern Australia V. Interactions between northern L. ewingi and adjacent taxa

1978 ◽  
Vol 26 (1) ◽  
pp. 175 ◽  
Author(s):  
GF Watson ◽  
MJ Littlejohn
Keyword(s):  
Small Area ◽  
Character Displacement ◽  
Reproductive Character Displacement ◽  
Genetic Compatibility ◽  
Natural Interaction ◽  
Call Structure ◽  
Environmental Features ◽  
Mating Call ◽  
Eastern Australia ◽  
High Level

A small area of overlap with hybridization characterizes the interaction between northern L. ewingi and L. paraewingi. Although significant levels of postmating isolation exist between the taxa, no evidence of reproductive character displacement in mating-call structure is apparent within the contact zone. No obvious environmental features appear to correlate with the position of the zone. Northern L. ewingi and L. verreauxi alpina also form a hybrid zone where their ranges meet, and the position of the zone appears to be correlated with altitude. The taxa are characterized by a high level of genetic compatibility and no mating-call differentiation is evident. However, despite hybridization with adjacent taxa, the distinctness of northern L. ewingi is maintained away from the areas of interaction, and hence it is considered specifically distinct from L. paraewingi and L. v. alpina. No natural interaction between northern L. ewingi and L. ewingi has been located. However, they are considered to be conspecific because of: their morphological resemblance; the high level of genetic compatibility between them; and, the similarity of each of their interactions with L. paraewingi and with L. v. alpina.

The Litoria ewingi Complex (Anura: Hylidae) in South-Eastern Australia VII.* Mating Call Structure and Gentic Compatibility across a Narrow Hybrid Zone between L. ewingi and L. parawingi

1983 ◽  
Vol 31 (2) ◽  
pp. 193 ◽  
Author(s):  
MJ Littlejohn ◽  
GF Watson
Keyword(s):  
Hybrid Zone ◽  
Parental Species ◽  
Allopatric Population ◽  
Minimum Width ◽  
Call Structure ◽  
Allopatric Populations ◽  
South Eastern ◽  
Mating Call ◽  
Eastern Australia

On the basis of the number of pulses per repeated note and of repeated notes per call for individual males, the interaction between Litoria ewingi and L. paraewingi in the region of the Tallarook (northern) transect is interpreted as a transitional hybrid zone, with populations consisting of hybrids and individuals of only one or other parental species. The Tallarook transect thus differs from the Glenburn (southern) transect, which is considered to be an overlap of both parental species together with recombination products. The minimum width of the zone in the area of the Tallarook transect is estimated to be 25 km, compared with 5 km for the Glenburn transect. Levels of partial and total anophthalmia were assessed in progeny from in vitro crosses involving a total of 27 males from both transects whose calls had been recorded and analysed, and females of L. ewingi from adjacent allopatry (a measure of the genetic representation of L. paraewingi). The results are, with one exception, consistent with the mating-call structure of these males. As was found with the Glenburn transect, calls of males of L. paraewingi from an allopatric population on the Tallarook transect close to the zone of interaction are more distinctive from calls of L. ewingi in pulses per repeated note than are those of distant allopatric populations of L. paraewingi. This finding is consistent with the suggestion that the products of reinforcing selection may be accumulating near the zone of interaction.

Studies in Australian amphibia III. The limnodynastes dorslis complex (Anura : Leptodactylidae)

1972 ◽  
Vol 20 (2) ◽  
pp. 165 ◽  
Author(s):  
AA Martin
Keyword(s):  
Western Australia ◽  
Hybrid Zone ◽  
Adult Male ◽  
Dominant Frequency ◽  
The Other ◽  
Hybrid Zones ◽  
Species Status ◽  
Call Structure ◽  
Mating Call ◽  
Male Morphology

The L. dorsalis complex is distributed extensively through coastal Australia, the Dividing Range, and parts of the western slopes and plains. Six subspecies have been described in the complex. Four of these are raised to species status and two additional subspecies are described. The complex thus comprises eight taxa in all: L. dorsalis, L. dumerili dumerili, L. d. insularis, L. d. grayi, L. d. variegatus, L, d. fryi, L. interioris, and L. terraereginae. The taxa were compared using two main criteria: adult male morphology and mating-call structure. Topotypic or near-topotypic samples of each form were obtained to ensure that comparisons were valid. L. dorsalis is restricted to Western Australia and is disjunctly allopatric to all the other forms in the complex. The eastern taxa have mainly parapatric distributions with several areas of contact between them. Where the range of L. d. dumerili comes into contact with those of L. d. insularis and L. d. variegatus, broad hybrid zones (up to 240 km wide) are formed. L. d. dumerili and L. d, grayi also appear to hybridize extensively. Where the range of L. d. dumerili contacts that of L. interioris a narrower hybrid zone (25-32km wide) is formed. Both L. d, dumerili and L. interioris have achieved sympatry with L, termereginae without any evidence of hybridization. The types of contact interactions can be related to the levels of divergence, particularly in mating-call structure, between the forms. Thus the calls of L, d. dumerili, L. d. insularis, L. d, grayi, and L. d. variegatus are all very similar. The call of L. interioris is quantitatively different to that of L. d. dumerili, with a lower dominant frequency,

The litoria ewingi complex (Anura : Hylidae) in south-eastern Australia IV. Variation in mating-call structure across a narrow hybrid zone between L. ewingi ad L.paraewingi

1976 ◽  
Vol 24 (2) ◽  
pp. 283 ◽  
Author(s):  
MJ Littlejohn
Keyword(s):  
Hybrid Zone ◽  
Parental Species ◽  
Character Displacement ◽  
Pulse Repetition ◽  
Reproductive Character Displacement ◽  
Genetic Incompatibility ◽  
Call Structure ◽  
Mating Call ◽  
Eastern Australia ◽  
Mating Calls

The presence of mating calls characteristic of both parental species, and of intermediate calls, within the zone of contact between L. ewingi and L. paraewingi supports the earlier interpretation that the interaction is an overlap with hybridization. Pulse repetition rates are similar throughout the transect, and there are no clear indications of reproductive character displacement within the hybrid zone, even though marked one-way genetic incompatibility is present. However, calls from close allopatry are more distinctive than those from distant allopatry, mainly in pulses per repeated note (a meristic character reflecting differences in note duration), suggesting that the effects of reinforcing selection may be accumulating in the proximity of the zone of interaction.

scholarly journals Graph-Based Construction of 3D Korean Giwa House Models

Buildings ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 68
Author(s):  
Mankyu Sung
Keyword(s):  
Data Structure ◽  
Computer Graphics ◽  
Real Time ◽  
Texture Image ◽  
Time Rate ◽  
Commercial Software ◽  
Spline Curve ◽  
High Level ◽  
Complicated Part ◽  
Different Parts

This paper proposes a graph-based algorithm for constructing 3D Korean traditional houses automatically using a computer graphics technique. In particular, we target designing the most popular traditional house type, a giwa house, whose roof is covered with a set of Korean traditional roof tiles called giwa. In our approach, we divided the whole design processes into two different parts. At a high level, we propose a special data structure called ‘modeling graphs’. A modeling graph consists of a set of nodes and edges. A node represents a particular component of the house and an edge represents the connection between two components with all associated parameters, including an offset vector between components. Users can easily add/ delete nodes and make them connect by an edge through a few mouse clicks. Once a modeling graph is built, then it is interpreted and rendered on a component-by-component basis by traversing nodes in a procedural way. At a low level, we came up with all the required parameters for constructing the components. Among all the components, the most beautiful but complicated part is the gently curved roof structures. In order to represent the sophisticated roof style, we introduce a spline curve-based modeling technique that is able to create curvy silhouettes of three different roof styles. In this process, rather than just applying a simple texture image onto the roof, which is widely used in commercial software, we actually laid out 3D giwa tiles on the roof seamlessly, which generated more realistic looks. Through many experiments, we verified that the proposed algorithm can model and render the giwa house at a real time rate.

Acoustic analysis of an intergrade zone between two call races of the Limnodynastes tasmaniensis complex (Anura : Leptodactylidae) in south-eastern Australia

1975 ◽  
Vol 23 (1) ◽  
pp. 113 ◽  
Author(s):  
MJ Littlejohn ◽  
JD Roberts
Keyword(s):  
Acoustic Analysis ◽  
Secondary Contact ◽  
Ecological Gradient ◽  
North Central ◽  
Call Structure ◽  
Central Victoria ◽  
South Eastern ◽  
Eastern Australia ◽  
Mating Calls ◽  
South Eastern Australia

Mating calls of the northern and southern call races of the L. tasmaniensis complex are described. Analysis of call structure along a transect across the main contact between these allopatric forms in north central Victoria indicates that there is a zone of intergradation between 90 and 135 km wide, about 215 km long and with a north-westerly orientation. The interaction is interpreted as a secondary contact in which there is hybrid or recombinant superiority along a subtle ecological gradient.

scholarly journals Levels of reactive nitrogen in surface and ground water samples obtained from different parts of Bangladesh

2014 ◽  
Vol 38 (1) ◽  
pp. 75-82 ◽  
Author(s):  
M Anowar K Parvez ◽  
Mahfuza Marzan ◽  
Syeda Moriam Liza ◽  
Zia Uddin Ahmed
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Ground Water ◽  
Water Samples ◽  
Ammonia Concentration ◽  
Reactive Nitrogen ◽  
Tube Well ◽  
High Level ◽  
Academy Of Sciences ◽  
Different Parts

A total of 114 water samples collected from different parts of Bangladesh were analyzed for the level of reactive nitrogen species NO3 and NH3. Nitrate was determined in 20 surface water, 28 motorized deep tube well and 66 hand operated tube well samples. Ammonia was determined in 18 surface water, 14 deep tube well and 49 hand operated tube well samples. These sites were randomly selected. Nitrate levels were found to be generally low (below 3 mg/l) in 112 of the 114 samples tested, which is much below permissible level of 10 mg/l of drinking water in Bangladesh. Ammonia concentration was, however, found to be about 4 mg/l in majority of the samples tested which is higher than maximum permissible limit of 0.5 mg/l in drinking water. Possible reasons for low level of nitrate and relatively high level of ammonia in surface and ground water samples in Bangladesh is discussed DOI: http://dx.doi.org/10.3329/jbas.v38i1.20214 Journal of Bangladesh Academy of Sciences, Vol. 38, No. 1, 75-82, 2014

Extensive hybridization between two Andean warbler species with shallow divergence in mtDNA

The Auk ◽  
2021 ◽  
Vol 138 (1) ◽  
Author(s):  
Laura N Céspedes-Arias ◽  
Andrés M Cuervo ◽  
Elisa Bonaccorso ◽  
Marialejandra Castro-Farias ◽  
Alejandro Mendoza-Santacruz ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Contact Zone ◽  
Hybrid Zone ◽  
Secondary Contact ◽  
Tropical Andes ◽  
Phenotypic Data ◽  
Geographic Ranges ◽  
Intermediate Phenotypes ◽  
Ecological Barriers

Abstract Studying processes acting on differentiated populations upon secondary contact, such as hybridization, is important to comprehensively understand how species are formed and maintained over time. However, avian speciation studies in the tropical Andes have largely focused on the role of topographic and ecological barriers promoting divergence in allopatry, seldom examining hybridization and introgression. We describe a hybrid zone involving 2 closely related Andean warblers (Parulidae), the Golden-fronted Redstart (Myioborus ornatus), and the Spectacled Redstart (Myioborus melanocephalus). Geographic ranges of these species abut near the Colombia-Ecuador border and many specimens from the region exhibit intermediate phenotypes, but a formal description of phenotypic variation in the contact zone was heretofore lacking. We collected specimens across a transect encompassing the area where ranges abut and areas where only “pure” parental phenotypes of M. ornatus chrysops and M. melanocephalus ruficoronatus occur. We described variation in plumage traits including patterns of head and ventral coloration and tail markings based on 321 specimens. To describe genetic variation in the contact zone and over a broader phylogeographic context, we used sequences of the mitochondrial ND2 gene for 219 individuals across the transect and the entire range of both species, including all subspecies, from Venezuela to Bolivia. We documented a hybrid zone ~200 km wide based on head coloration, where intermediate plumage phenotypes are most common and “pure” forms do not overlap geographically, consistent with extensive hybridization. Across the range of the M. ornatus–M. melanocephalus complex, mitochondrial genetic structure was shallow, with genetic breaks only coinciding clearly with one topographic feature. Such a low genetic structure is striking given the high diversity in plumage phenotypes and the current taxonomy of the group. Our phenotypic data suggest that barriers to hybridization are not strong, and allow us to postulate hypotheses to be tested using forthcoming genomic data.

Modern problems of regionalization of territories and human adaptation in regions with extreme natural and climatic conditions

2021 ◽  
Author(s):  
A.L. Maksimov
Keyword(s):  
Environmental Factors ◽  
Environmental Conditions ◽  
Allostatic Load ◽  
Climatic Conditions ◽  
Extreme Conditions ◽  
Human Adaptation ◽  
Nonspecific Resistance ◽  
Key Words Adaptation ◽  
High Level ◽  
Selection Of

The paper considers modern approaches to the zoning of territories and the selection of people for life in extreme environmental conditions, taking into account modern geopolitical challenges. It is shown that it is possible, based on the allostasis concept, to conduct not only the selection of persons with a high level of nonspecific resistance, but also to quantify the degree of extremity of environmental factors using the standard represpiration test. Key words: adaptation, extreme conditions, selection, hypoxia, cold, rerespiration, allostatic load.

Combating Corruption through e-Governance in India

2013 ◽  
pp. 233-244 ◽  
Author(s):  
Durga Shanker Mishra
Keyword(s):  
Literature Review ◽  
Business Process ◽  
Business Process Reengineering ◽  
Process Reengineering ◽  
Efficient System ◽  
Delivery Services ◽  
High Level ◽  
Opening Up ◽  
Different Parts

Studies have shown a prevalence of high level of corruption in the Indian Administrative System, which adversely affects the day-to-day lives of common citizens. This chapter examines the role of e-governance in combating corruption in delivering public services. Through a literature review assessing the outcomes of a few e-governance initiatives related to improving service delivery in different parts of India, this chapter argues that even though technology assists in instituting a transparent, accountable, consistent, reliable, and efficient system for delivery services, it cannot overcome corruption by itself. It will require political will, focused administrative strategy, business process reengineering for simplifying and opening up the system, and persistent efforts to ensure that corruption entrepreneurs do not subvert the gains of the technology.

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