scholarly journals Сравнение эколого-климатических ниш двух видов ковылей – Stipa sareptana A.K. Becker и S. krylovii Roshev. (Poaceae)

2017 ◽  
Vol 7 (4) ◽  
pp. 263-269 ◽  
Author(s):  
P. D. Gudkova ◽  
M. V. Olonova ◽  
D. S. Feoktistov
Keyword(s):  
Related Species ◽  
Significant Contribution ◽  
Climatic Conditions ◽  
Ecological Niches ◽  
Mean Annual Temperature ◽  
Morphological Pattern ◽  
Closely Related Species ◽  
The Mean ◽  
Gis Methods ◽  
Subordinate Role

Each species besides of having the unique morphological pattern also has an unique ecologo-climatic niche and geographical range. The study of ecologico-climatic and geographic divergence can make significant contribution to understanding of the species genesis and its volume. The purpose of this paper was to compare the ecologo-climatic niches of the closely related species Stipa sareptana and S. krylovii in order to reveal their identity. The research allowed specifying the areas of both species. Using GIS methods and based on the points of presence and six independent bioclimatic characters, their potential ranges – areas where the climatic conditions are favorable for growth – were identified and ecologo-climatic niches revealed. It was established that the most important factors determining the distribution of S. krylovii and S. sareptana are the mean annual temperature and seasonality of precipitation. Other factors play a subordinate role. The comparison of ecological niches, generated by MaxEnt, showed their differences at a statistically significant level.

The Pollination Biology of Dendrobium speciosum Smith: a Case of False Advertising?

1988 ◽  
Vol 36 (2) ◽  
pp. 145 ◽  
Author(s):  
AT Slater ◽  
DM Calder
Keyword(s):  
Related Species ◽  
Fruit Set ◽  
Natural Populations ◽  
Climatic Conditions ◽  
Closely Related Species ◽  
High Occurrence ◽  
Bright Yellow ◽  
Pollination Mechanisms ◽  
Sunny Weather ◽  
Olfactory Display

Potential pollinators of Dendrobium speciosum are attracted to the plant by large, cream to yellow, finely segmented, aromatic inflorescences. Plants in natural populations flower synchronously, produc- ing a massive display. Osmophores scattered over the perianth produce a strong, sweet scent in sunny weather. Nectar-seeking insects are guided to the central, reproductive area of the flower by the colour gradation of the perianth, including an area of high U.V. reflection near the centre, and a bright yellow ridge along the labellum. A tube formed by the labellum and column directs the potential pollinators. The flower, however, produces no nectar. Flowers vary in size within the six recognised varieties of D. speciosum and are pollinated when visited by bees of appropriate size. Post-pollination closure of flowers prevents further access by potential pollinators. The dendrobium beetle and larvae feed on the plant and inflorescences and play no part in pollination. The low fruit set, characteristic of this species, is considered to be a combined result of self-infertility and the absence of rewards offered by the flower. The specific climatic conditions during which pollinators visit the flowers are also important. The attraction and pollination mechanisms are similar among all observed varieties of D. speciosum as well as some closely related species, possibly explaining the high occurrence of hybrids within this group. It is concluded that D. speciosum provides a visual and olfactory display through the production of a large number of hermaphrodite non-rewarding flowers on each inflorescence, and relies on infrequent outcrosses for successful pollination.

scholarly journals Parallel evolution of metazoan mitochondrial proteins

2016 ◽  
Author(s):  
Galya V. Klink ◽  
Georgii A. Bazykin
Keyword(s):  
Amino Acid ◽  
Related Species ◽  
Parallel Evolution ◽  
Phylogenetic Reconstruction ◽  
Acid Sites ◽  
Mitochondrial Proteins ◽  
Phylogenetic Distance ◽  
Closely Related Species ◽  
Epistatic Interactions ◽  
The Mean

AbstractAmino acid propensities at amino acid sites change with time due to epistatic interactions or changing environment, affecting the probabilities of fixation of different amino acids. Such changes should lead to an increased rate of homoplasies (reversals, parallelisms, and convergences) at closely related species. Here, we reconstruct the phylogeny of twelve mitochondrial proteins from several thousand metazoan species, and measure the phylogenetic distances between branches at which either the same allele originated repeatedly due to homoplasies, or different alleles originated due to divergent substitutions. The mean phylogenetic distance between parallel substitutions is ∼20% lower than the mean phylogenetic distance between divergent substitutions, indicating that a variant fixed in a species is more likely to be deleterious in a more phylogenetically remote species, compared to a more closely related species. These findings are robust to artefacts of phylogenetic reconstruction or of pooling of sites from different conservation classes or functional groups, and imply that single-position fitness landscapes change at rates similar to rates of amino acid changes.

scholarly journals Temporal niche partitioning of Swiss black scavenger flies in relation to season and substrate age (Diptera, Sepsidae)

2019 ◽  
Vol 3 ◽  
pp. 1-10 ◽  
Author(s):  
Patrick T. Rohner ◽  
Jean-Paul Haenni ◽  
Athene Giesen ◽  
Juan Pablo Busso ◽  
Martin A. Schäfer ◽  
...  
Keyword(s):  
Related Species ◽  
Species Coexistence ◽  
Species Turnover ◽  
Niche Partitioning ◽  
Temporal Distribution ◽  
Niche Differentiation ◽  
Ecological Niches ◽  
Phylogenetic Distance ◽  
Closely Related Species ◽  
Temporal Niche

Understanding why and how multiple species manage to coexist represents a primary goal of ecological and evolutionary research. This is of particular relevance for communities that depend on resource rich ephemeral habitats that are prone to high intra- and interspecific competition. Black scavenger flies (Diptera: Sepsidae) are common and abundant acalyptrate flies associated with livestock dung decomposition in human-influenced agricultural grasslands worldwide. Several widespread sepsid species with apparently very similar ecological niches coexist in Europe, but despite their ecological role and their use in evolutionary ecological research, our understanding of their ecological niches and spatio-temporal distribution is still rudimentary. To gain a better understanding of their ecology, we here investigate niche partitioning at two temporal scales. First, we monitored the seasonal occurrence, often related to thermal preference, over multiple years and sites in Switzerland that differ in altitude. Secondly, we also investigate fine-scale temporal succession on dairy cow pastures. In accordance with their altitudinal and latitudinal distribution in Europe, some species were common over the entire season with a peak in summer, hence classified as warm-loving, whereas others were primarily present in spring or autumn. Phenological differences thus likely contribute to species coexistence throughout the season. However, the community also showed pronounced species turnover related to cow pat age. Some species colonize particularly fresh dung and are gradually replaced by others. Furthermore, the correlation between co-occurrence and phylogenetic distance of species revealed significant under-dispersion, indicating that more closely related species are frequently recovered at the same location. As a whole, our data suggests temporal niche differentiation of closely related species that likely facilitates the rather high species diversity on Swiss cattle pastures. The underlying mechanisms allowing close relatives to co-occur however require further scrutiny.

scholarly journals Relationships between the distribution of Galba truncatula (Gastropoda: Lymnaeidae) climatic conditions and the altitude of municipalities in Haute Vienne (France)

2018 ◽  
Vol 54 ◽  
pp. 19
Author(s):  
Gilles Dreyfuss ◽  
Philippe Vignoles ◽  
Daniel Rondelaud
Keyword(s):  
Retrospective Study ◽  
Habitat Type ◽  
Acid Soils ◽  
Climatic Conditions ◽  
Annual Rainfall ◽  
Mean Annual Temperature ◽  
Galba Truncatula ◽  
Mean Annual Rainfall ◽  
The Mean

A retrospective study on 7407 populations of Galba truncatula found in the department of Haute Vienne for 37 years (1970–2006) was carried out to determine if altitude and climate on acid soils had an effect on the distribution of populations and the characteristics of their habitats. Out of a total of 13 478 water points surveyed in 179 municipalities, the overall frequency of snail populations was 54.9% but varied with the habitat type and the municipality on which these water points are located. The frequency of snail populations significantly decreased when the mean altitude of municipalities or their mean annual rainfall increased. Conversely, this frequency significantly increased with increasing mean annual temperature. The characteristics of habitats were analysed for 6281 populations in relation to the mean altitude of municipalities. The area of G. truncatula habitats and the density of overwintering snails per m2 of habitat significantly decreased with increasing altitude. On the acid soils of Haute Vienne, the distribution of G. truncatula populations is closely related to the altitude and climatic conditions of municipalities.

scholarly journals The spindle assembly checkpoint and speciation

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9073
Author(s):  
Robert C. Jackson ◽  
Hitesh B. Mistry
Keyword(s):  
Related Species ◽  
Spindle Assembly Checkpoint ◽  
Evolutionary Dynamics ◽  
Chromosomal Rearrangements ◽  
Spindle Assembly ◽  
Selective Advantage ◽  
Ecological Niches ◽  
Geographical Isolation ◽  
Closely Related Species ◽  
Definition Of

A mechanism is proposed by which speciation may occur without the need to postulate geographical isolation of the diverging populations. Closely related species that occupy overlapping or adjacent ecological niches often have an almost identical genome but differ by chromosomal rearrangements that result in reproductive isolation. The mitotic spindle assembly checkpoint normally functions to prevent gametes with non-identical karyotypes from forming viable zygotes. Unless gametes from two individuals happen to undergo the same chromosomal rearrangement at the same place and time, a most improbable situation, there has been no satisfactory explanation of how such rearrangements can propagate. Consideration of the dynamics of the spindle assembly checkpoint suggest that chromosomal fission or fusion events may occur that allow formation of viable heterozygotes between the rearranged and parental karyotypes, albeit with decreased fertility. Evolutionary dynamics calculations suggest that if the resulting heterozygous organisms have a selective advantage in an adjoining or overlapping ecological niche from that of the parental strain, despite the reproductive disadvantage of the population carrying the altered karyotype, it may accumulate sufficiently that homozygotes begin to emerge. At this point the reproductive disadvantage of the rearranged karyotype disappears, and a single population has been replaced by two populations that are partially reproductively isolated. This definition of species as populations that differ from other, closely related, species by karyotypic changes is consistent with the classical definition of a species as a population that is capable of interbreeding to produce fertile progeny. Even modest degrees of reproductive impairment of heterozygotes between two related populations may lead to speciation by this mechanism, and geographical isolation is not necessary for the process.

scholarly journals Primate Torpor Expression: Ghost of the Climatic Past

Physiology ◽  
2016 ◽  
Vol 31 (6) ◽  
pp. 398-408 ◽  
Author(s):  
Kathrin H. Dausmann ◽  
Lisa Warnecke
Keyword(s):  
Related Species ◽  
Habitat Type ◽  
Climatic Conditions ◽  
Primate Species ◽  
Daily Torpor ◽  
Closely Related Species ◽  
Lower Elevation ◽  
Bodily Function ◽  
Glacial Periods ◽  
Free Ranging

Torpor, the controlled depression of virtually all bodily function during scarce periods, was verified in primates under free-ranging conditions less than two decades ago. The large variety of different torpor patterns found both within and among closely related species is particularly remarkable. To help unravel the cause of these variable patterns, our review investigates primate torpor use within an evolutionary framework. First, we provide an overview of heterothermic primate species, focusing on the Malagasy lemurs, and discuss their use of daily torpor or hibernation in relation to habitat type and climatic conditions. Second, we investigate environmental characteristics that may have been involved in shaping the high variability of torpor expression found in lemurs today. Third, we examine potential triggers for torpor use in lemurs. We propose the “torpor refugia hypothesis” to illustrate how disparate primate torpor patterns possibly evolved in response to environmental cues during glacial periods, when animals were restricted to different refuge habitats along riverine corridors. For example, individuals enduring harsher conditions at higher altitudes likely developed seasonal hibernation, whereas those inhabiting lower elevation river catchments might have coped with unfavorable conditions by employing daily torpor. The ultimate stimuli triggering torpor use today likely differ between the different habitats of Madagascar. The broad diversity of torpor patterns in lemurs among closely related species, both within the same and in distinctly different habitat types, provides an ideal base for research into the stimuli for torpor use in endotherms in general. Our hypothesis highlights the importance of considering the environmental conditions under which ecosystems and species evolved when trying to explain physiological adaptations seen today.

scholarly journals Zum Problem der Stabilität der Klimabedingungen in Westsibirien während der Glaziale und Interglaziale

1960 ◽  
Vol 11 (1) ◽  
pp. 77-87
Author(s):  
W. Weischet
Keyword(s):  
Western Siberia ◽  
Meridional Circulation ◽  
Climatic Conditions ◽  
Summer Temperature ◽  
Deciduous Forests ◽  
The Arctic ◽  
Mean Annual Temperature ◽  
Last Glaciation ◽  
The Mean ◽  
Glacial Periods

Abstract. The depression values of the summer temperature and also of the mean annual temperature in Western Siberia during the last glaciation, have been deduced. This calculation has been based on the different position of the boreal boundaries of the tundra and the continental deciduous forests during the ice ages and at the present time. According to these calculations the following depressions of summer temperature have been obtained: 5-8° C near the arctic circle and 2-4° C in the latitude of 50° North, in comparison with the 10-12° C depression in Central Europe. Afterwards it has been discussed whether or not these relatively small depressions can be explained exclusively on the basis of the higher continentality of the central part of Eurasia in comparison with the western or eastern part of this continent. As this seems to be impossible, it is necessary to look for other facts that could be related to this problem. In the opinion of the author the relative stability of climatic conditions in Western Siberia during the whole Quaternary could be easily explained by the change between the meridional-circulation (low-index-type), prevailing during the glacial periods, and the reinforced zonal-circulation (high-index-type) during the interglacial and postglacial periods.

scholarly journals unity in the wild variety of nature, or just variety?

2005 ◽  
Vol 28 (4) ◽  
pp. 606-608 ◽  
Author(s):  
i. c. mcmanus
Keyword(s):  
Phylogenetic Analysis ◽  
Related Species ◽  
Ecological Niches ◽  
Closely Related Species ◽  
Behavioural Asymmetries ◽  
In The Wild ◽  
Wild Variety ◽  
Underlying Mechanisms

although there are some common underlying mechanisms for many nonhuman behavioural asymmetries, the evidence at present is not compelling for commonalities in cerebral organisation across vertebrates. phylogenetic analysis of detour behaviour in fish suggests that more closely related species are not particularly similar in the direction of turning; contingency and demands of ecological niches may better explain such asymmetries.

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