Electrophoretic evidence for multiple origins of triploid forms in the Ambystoma laterale–jeffersonianum complex

1989 ◽  
Vol 67 (2) ◽  
pp. 350-356 ◽  
Author(s):  
Leslie A. Lowcock ◽  
James P. Bogart
Keyword(s):  
East Coast ◽  
Eastern North America ◽  
Gene Exchange ◽  
Heterozygous Condition ◽  
Southern Ontario ◽  
Northwestern Ontario ◽  
Multiple Origins ◽  
Wide Range ◽  
Ambystoma Laterale ◽  
Hybrid Complexes

Variable allele frequencies and a wide range of genotypes in samples of triploid Ambystoma laterale–jeffersonianum (LLJ) hybrids indicate that these forms have arisen on many occasions. Though suggested previously, we show here the first clear evidence that this has taken place, with examples from two loci (Pgm-B, M-Aat-A) that have different biogeographic allele distributions. (i) A polymorphism at Pgm-B in Ambystoma laterale, otherwise restricted to northwestern Ontario, was found in both diploid A. laterale and co-occurring LLJ triploids in southern Ontario, where it is confined to the tip of the Bruce Peninsula. Diploids and triploids not possessing the allele also occur here and throughout the range of the A. laterale–jeffersonianum complex in eastern North America. (ii) An east coast A. laterale polymorphism at the M-Aat-A locus is also represented in both the homozygous and heterozygous condition within syntopic diploids and triploids in single populations. These data demonstrate multiple origins of triploidy, suggest continual gene exchange between diploids and triploids, and are analogous to data presented for other hybrid complexes of Ambystoma. The origins and distribution of the alleles in question are briefly considered, as they are of some biogeographic interest.

The Identification and Study of Indian Shell Middens in Eastern North America: 1643–1861

1986 ◽  
Vol 6 (3) ◽  
pp. 227-243 ◽  
Author(s):  
Andrew L. Christenson
Keyword(s):  
Nineteenth Century ◽  
Civil War ◽  
North America ◽  
East Coast ◽  
Eastern North America ◽  
Shell Midden ◽  
Shell Middens ◽  
Work Done

Although the interest in shell middens in North America is often traced to reports of the discoveries in Danish kjoekkenmoeddings in the mid-nineteenth century, extensive shell midden studies were already occurring on the East Coast by that time. This article reviews selected examples of this early work done by geologists and naturalists, which served as a foundation for shell midden studies by archaeologists after the Civil War.

Distribution of the middorsal stripe dimorphism in the wood frog, Rana sylvatica, in eastern North America

1980 ◽  
Vol 58 (9) ◽  
pp. 1643-1651 ◽  
Author(s):  
Frederick W. Schueler ◽  
Francis R. Cook
Keyword(s):  
United States ◽  
North America ◽  
Rana Sylvatica ◽  
Wood Frog ◽  
Eastern North America ◽  
Hudson Bay ◽  
Northeastern United States ◽  
Southern Ontario ◽  
Maritime Canada ◽  
Eurasian Species

The frequency of the middorsally striped morph of Rana sylvatica in Ontario and Manitoba varies from absence in southern Ontario to 80% on the coast of Hudson Bay, with a general value of 20–30% in the boreal forest, a rise to 50% on the forest–grassland ecotone in southern Manitoba, and a decline westward to 20% on the edge of the prairies. This morph is rare in the northeastern United States and Maritime Canada. The suggested relationship between its frequency and the "grassiness" of the background on which predators view it is reexamined, and it is suggested that a linkage with earlier transformation as demonstrated in Eurasian species may explain certain anomalies.

SEXUAL BEHAVIOR AND THE CLASSIFICATION OF THE PHILODROMUS RUFUS COMPLEX IN NORTH AMERICA (ARANEIDA: THOMISIDAE)

1967 ◽  
Vol 45 (4) ◽  
pp. 453-459 ◽  
Author(s):  
C. D. Dondale
Keyword(s):  
Sexual Behavior ◽  
North America ◽  
Great Lakes ◽  
Pacific Coast ◽  
Eastern North America ◽  
Northern Ontario ◽  
Southern Ontario ◽  
The Pacific ◽  
Mating Behaviors

The mating behaviors of Philodromus rufus-like spiders from the Pacific coast, northern Ontario, and southern Ontario near Belleville revealed two species and a subspecies. P. rufus Walckenaer is identified as a transcontinental species in which the males vibrate their legs in courtship and possess an "angular" retro-lateral apophysis on the palpal tibia. P. rufus vibrans Dondale is a small, heavily-speckled subspecies of rufus. The second species is P. exilis Banks, in which the males do not vibrate and have a "non-angular" apophysis, and which occurs in the Great Lakes-St. Lawrence-Acadian forests of eastern North America.

The extent of old-growth Thuja occidentalis on cliffs of the Niagara Escarpment

1991 ◽  
Vol 69 (7) ◽  
pp. 1628-1636 ◽  
Author(s):  
D. W. Larson ◽  
P. E. Kelly
Keyword(s):  
Cross Sections ◽  
Forest Ecosystems ◽  
Forest Ecology ◽  
Eastern North America ◽  
Old Growth ◽  
Southern Ontario ◽  
Thuja Occidentalis ◽  
Selective Sampling ◽  
Niagara Escarpment ◽  
Old Growth Forest

Extensive random sampling of populations of Thuja occidentalis growing on vertical cliffs of the Niagara Escarpment in southern Ontario, Canada, was conducted to determine the extent of an old-growth forest that had recently been described. Nine sites distributed along the length of the escarpment were intensively sampled and from these, 1254 increment cores or cross sections were obtained from 872 trees in all age categories. The results show that all cliffs support a broadly similar old-growth forest of stunted trees, but that statistically significant differences were found in the numbers of trees among sites. No large differences among sites were found in heights or diameters of trees. Maximum ages of 532 (sampled) and 814 years (estimated) were found in the random census, although in subsequent selective sampling, intact stems up to 1032 years were found. The incidence of fire and cutting by humans was also measured, but little evidence of such disturbances was found. It is concluded that exposed cliff faces of the Niagara Escarpment support one of the oldest, most extensive, and most intact old-growth forest ecosystems yet described for eastern North America. The opportunities for the study of basic forest ecology and especially for dendrochronology are considerable. Key words: Thuja occidentalis, old growth, Niagara Escarpment, cliff, age structures.

Geographic variation in a widespread perennial weed, Rumex crispus. The relative amounts of genetic and environmentally induced variation among populations

1982 ◽  
Vol 60 (10) ◽  
pp. 1928-1937 ◽  
Author(s):  
L. Hume ◽  
P. B. Cavers
Keyword(s):  
Genetic Variation ◽  
North America ◽  
Genetic Heterogeneity ◽  
Local Level ◽  
Adaptive Strategy ◽  
Eastern North America ◽  
Rumex Crispus ◽  
Perennial Weed ◽  
Wide Range ◽  
The World

Populations of Rumex crispus were sampled from eastern North America and Europe. The relative amounts of genetic variation and plasticity were examined, using 58 plant characters. About 61% of the total variation occurring in the experimental plants was accounted for by plasticity. The remaining 26% and 13% occurred within populations and among widespread populations, respectively. At the local level, there was little difference between variation occurring within genotypes and that within families (between maternal siblings). This suggests that the species is predominantly inbreeding. The majority of genetic variation occurs within populations at both the local and species' range levels.It was concluded that the species has large amounts of both flexibility and genetic heterogeneity. This adaptive strategy enables the species to survive under a very wide range of environmental situations and largely accounts for its becoming one of the most widely distributed plants in the world.

scholarly journals Redescription of Arundel formation Ornithomimosaur material and a reinterpretation of Nedcolbertia justinhofmanni as an “Ostrich Dinosaur”: Biogeographic implications

2016 ◽  
Author(s):  
Chase Doran Brownstein
Keyword(s):  
United States ◽  
North America ◽  
Early Cretaceous ◽  
Fossil Record ◽  
East Coast ◽  
The United States ◽  
Eastern North America ◽  
New Taxon ◽  
Western North America ◽  
The Past

The fossil record of dinosaurs from the Early Cretaceous of eastern North America is scant, and only a few sediments to the east of the continent are fossiliferous. Among them is the Arundel Formation of the east coast of the United States, which has produced among the best dinosaur faunas known from the Early Cretaceous of eastern North America. The diverse dinosaur fauna of this formation has been thoroughly discussed previously, but few of the dinosaur species originally described from the Arundel are still regarded as valid genera. Much of the Arundel material is in need of review and redescription. Among the fossils of dinosaurs from this formation are those referred to ornithomimosaurs. Here, I redescribe ornithomimosaur remains from the Arundel Formation which may warrant the naming of a new taxon of dinosaur. These remains provide key information on the theropods of the Early Cretaceous of Eastern North America. The description of the Arundel material herein along with recent discoveries of basal ornithomimosaurs in the past 15 years has allowed for comparisons with the coelurosaur Nedcolbertia justinhofmanni, suggesting the latter animal was a basal ornithomimosaurian dinosaur rather than a “generalized” coelurosaur. Comparisons between the Arundel ornithomimosaur and similar southeast Asian ornithomimosaurian material as well as ornithomimosaur remains from western North America suggest that a lineage of ornithomimosaurs with a metatarsal condition intermediate between that of basal and derived ornithomimosaurs was present through southeast Asia into North America, in turn suggesting that such animals coexisted with genera having a more primitive metatarsal morphology as seen in N. justinhofmanni.

Skating in the New World

2017 ◽  
Author(s):  
James R. Hines
Keyword(s):  
Eighteenth Century ◽  
North America ◽  
American Revolution ◽  
New World ◽  
East Coast ◽  
Eastern North America ◽  
Recreational Activity ◽  
Figure Skaters ◽  
The World ◽  
Important Center

This chapter discusses the development of skating in the New World. There is much evidence of skating activity throughout the Colonies in the years before the American Revolution. It was a recreational activity, with racing being especially popular, but as a discipline little is known about it. Bone skates as a practical solution for travel across frozen landscapes were discovered independently in various parts of the world. French trappers who worked in eastern North America learned from the Iroquois Indians the practice of tying bones to their feet to traverse frozen rivers. Thus, in North America as in Europe and Asia, skating on bones must have existed for thousands of years. Bladed skates, however, were probably unknown in the New World before the eighteenth century, perhaps introduced by British officers stationed in Nova Scotia following its seizure from the French in 1713. By the mid-eighteenth century, skating was practiced along the East Coast whenever ice was available. Philadelphia became skating's first important center and could boast of competent figure skaters.

The effects of bark quality on corticolous lichen community composition in urban parks of southern Ontario

Botany ◽  
2017 ◽  
Vol 95 (12) ◽  
pp. 1141-1149 ◽  
Author(s):  
L. McDonald ◽  
M. Van Woudenberg ◽  
B. Dorin ◽  
A.M. Adcock ◽  
R.T. McMullin ◽  
...  
Keyword(s):  
Community Composition ◽  
Tree Species ◽  
Urban Parks ◽  
Tree Bark ◽  
Significant Variable ◽  
Southern Ontario ◽  
Lichen Community ◽  
Wide Range ◽  
The City ◽  
Common Tree

Tree bark characteristics influence lichen colonization. To better understand how urban parks can be managed to maximize lichen biodiversity, we examined trees in seven parks throughout the City of Guelph in southern Ontario. We measured bark characteristics and lichen communities on four common tree species that have a wide range of pH: Acer platanoides L., Acer × freemanii E. Murray, Pinus resinosa Aiton, and Pinus strobes L. We recorded the lichen species on 99 trees, calculated the pH and fissuring of the bark, and determined the diameter at breast height (DBH) as a proxy for age. Gamma diversity on all trees included 18 lichen taxa. We used graphite bark rubbings analyzed in ImageJ 1.47v to calculate the degree of bark fissuring. We collected bark samples from each tree trunk and determined the acidity with a pH meter. Using multivariate analyses we show that lichen community composition is positively correlated with DBH and tree species, but the degree of fissuring did not have a significant effect. We could not statistically analyze pH independent of tree species, but our results suggest pH is not a significant variable. We show lichen biodiversity in urban parks can be increased by planting a variety of tree species at different ages.

scholarly journals Air–water CO<sub>2</sub> evasion from US East Coast estuaries

2017 ◽  
Vol 14 (9) ◽  
pp. 2441-2468 ◽  
Author(s):  
Goulven Gildas Laruelle ◽  
Nicolas Goossens ◽  
Sandra Arndt ◽  
Wei-Jun Cai ◽  
Pierre Regnier
Keyword(s):  
East Coast ◽  
Regional Scale ◽  
Global Scale ◽  
Biogeochemical Processes ◽  
Wide Range ◽  
Tidal Estuaries ◽  
Net Heterotrophy ◽  
Carbon Processing ◽  
Year 2000 ◽  
Us East Coast

Abstract. This study presents the first regional-scale assessment of estuarine CO2 evasion along the US East Coast (25–45° N). The focus is on 42 tidal estuaries, which together drain a catchment of 697 000 km2 or 76 % of the total area within this latitudinal band. The approach is based on the Carbon–Generic Estuary Model (C-GEM) that allows the simulation of hydrodynamics, transport, and biogeochemistry for a wide range of estuarine systems using readily available geometric parameters and global databases of seasonal climatic, hydraulic, and riverine biogeochemical information. Our simulations, performed using conditions representative of the year 2000, suggest that, together, US East Coast estuaries emit 1.9 Tg C yr−1 in the form of CO2, which corresponds to about 40 % of the carbon inputs from rivers, marshes, and mangroves. Carbon removal within estuaries results from a combination of physical (outgassing of supersaturated riverine waters) and biogeochemical processes (net heterotrophy and nitrification). The CO2 evasion and its underlying drivers show important variations across individual systems, but reveal a clear latitudinal pattern characterized by a decrease in the relative importance of physical over biogeochemical processes along a north–south gradient. Finally, the results reveal that the ratio of estuarine surface area to the river discharge, S∕Q (which has a scale of per meter discharged water per year), could be used as a predictor of the estuarine carbon processing in future regional- and global-scale assessments.

East Coast Cool-Weather Storms in the New York Metropolitan Region

2009 ◽  
Vol 48 (11) ◽  
pp. 2320-2330 ◽  
Author(s):  
H. Salmun ◽  
A. Molod ◽  
F. S. Buonaiuto ◽  
K. Wisniewska ◽  
K. C. Clarke
Keyword(s):  
New York ◽  
Storm Surge ◽  
East Coast ◽  
Reanalysis Data ◽  
Coastal Environment ◽  
Meteorological Conditions ◽  
Beach Erosion ◽  
Metropolitan Region ◽  
Wide Range ◽  
The Impact

Abstract New York coastal regions are frequently exposed to winter extratropical storm systems that exhibit a wide range of local impacts. Studies of these systems either have used localized water-level or beach erosion data to identify and characterize the storms or have used meteorological conditions from reanalysis data to provide a general regional “climatology” of storms. The use of meteorological conditions to identify these storms allows an independent assessment of impacts on the coastal environment and therefore can be used to predict the impacts. However, the intensity of these storms can exhibit substantial spatial variability that may not be captured by the relatively large scales of the studies using reanalysis data, and this fact may affect the localized assessment of storm impact on the coastal communities. A method that uses data from National Data Buoy Center stations in the New York metropolitan area to identify East Coast cool-weather storms (ECCSs) and to describe their climatological characteristics is presented. An assessment of the presence of storm conditions and a three-level intensity scale was developed using surface pressure data as measured at the buoys. This study identified ECCSs during the period from 1977 through 2007 and developed storm climatologies for each level of storm intensity. General agreement with established climatologies demonstrated the robustness of the method. The impact of the storms on the coastal environment was assessed by computing “storm average” values of storm-surge data and by examining beach erosion along the south shore of Long Island, New York. A regression analysis demonstrated that the best storm-surge predictor is based on measurements of significant wave height at a nearby buoy.

Sign in / Sign up

Export Citation Format

Share Document